From b4dd762364df67225386186dc0e601eaa8cae298 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Wed, 27 Oct 2021 17:34:18 -0700
Subject: [PATCH 01/19] Kind of working for Map types

---
 .../lib/src/debugger/debugger_controller.dart |  4 +-
 .../lib/src/debugger/debugger_model.dart      | 76 +++++++++++++++++--
 .../lib/src/debugger/variables.dart           |  4 +-
 packages/devtools_app/lib/src/utils.dart      |  8 +-
 .../lib/src/vm_service_wrapper.dart           |  5 +-
 .../macos/Runner.xcodeproj/project.pbxproj    |  5 ++
 packages/devtools_app/test/utils_test.dart    | 11 ++-
 7 files changed, 103 insertions(+), 10 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_controller.dart b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
index a9e1c34e7d5..f5a1a62baa5 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_controller.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
@@ -763,6 +763,8 @@ class DebuggerController extends DisposableController
     // Collecting frames for Dart web applications can be slow. At the potential
     // cost of a flicker in the stack view, display only the top frame
     // initially.
+    // Note: Should find a better solution for this.
+    //Currently, this means we fetch all variable objects twice. (Once here, and once in _getFullStack)
     if (await serviceManager.connectedApp.isDartWebApp) {
       _populateFrameInfo(
         [
@@ -949,7 +951,7 @@ class DebuggerController extends DisposableController
     final variables =
         frame.vars.map((v) => Variable.create(v, isolateRef)).toList();
     variables
-      ..forEach(buildVariablesTree)
+      ..forEach((v) => buildVariablesTree(v, offset: 0, count: 0))
       ..sort((a, b) => sortFieldsByName(a.name, b.name));
     return variables;
   }
diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index e76bddf0a7c..38fb47c667f 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -334,6 +334,8 @@ Future<void> addExpandableChildren(
 Future<void> buildVariablesTree(
   Variable variable, {
   bool expandAll = false,
+  int offset,
+  int count,
 }) async {
   final ref = variable.ref;
   if (!variable.isExpandable || variable.treeInitializeStarted || ref == null)
@@ -382,13 +384,29 @@ Future<void> buildVariablesTree(
   }
   if (instanceRef != null && serviceManager.service != null) {
     try {
-      final dynamic result = await serviceManager.service
-          .getObject(variable.ref.isolateRef.id, instanceRef.id);
+      final dynamic result = await serviceManager.service.getObject(
+          variable.ref.isolateRef.id, instanceRef.id,
+          offset: offset, count: count);
       if (result is Instance) {
         if (result.associations != null) {
-          variable.addAllChildren(
-              _createVariablesForAssociations(result, isolateRef));
+          if (variable.childCount > 50) {
+            var offset = 0;
+            while (offset + 50 < variable.childCount) {
+              variable.addChild(
+                Variable.grouping(variable.ref, offset: offset, count: 50),
+              );
+              offset = offset + 50;
+            }
+            final remainder = variable.childCount - offset;
+            final childVar = Variable.grouping(variable.ref,
+                offset: offset, count: remainder);
+            variable.addChild(childVar);
+          } else {
+            variable.addAllChildren(
+                _createVariablesForAssociations(result, isolateRef));
+          }
         } else if (result.elements != null) {
+          // this is for a list
           variable
               .addAllChildren(_createVariablesForElements(result, isolateRef));
         } else if (result.bytes != null) {
@@ -657,7 +675,12 @@ List<Variable> _createVariablesForFields(
 // TODO(jacobr): consider a new class name. This class is more just the data
 // model for a tree of Dart objects with properties rather than a "Variable".
 class Variable extends TreeNode<Variable> {
-  Variable._(this.name, ref, this.text) : _ref = ref {
+  Variable._(this.name, ref, this.text,
+      {int offset, int count, bool isGrouping = false})
+      : _ref = ref,
+        _offset = offset,
+        _count = count,
+        _isGrouping = isGrouping {
     indentChildren = ref?.diagnostic?.style != DiagnosticsTreeStyle.flat;
   }
 
@@ -702,11 +725,35 @@ class Variable extends TreeNode<Variable> {
     return Variable._(null, null, text);
   }
 
+  factory Variable.grouping(
+    GenericInstanceRef ref, {
+    @required int offset,
+    @required int count,
+  }) {
+    return Variable._(
+      null,
+      ref,
+      '[$offset - ${offset + count}]',
+      offset: offset,
+      count: count,
+      isGrouping: true,
+    );
+  }
+
   final String text;
   final String name;
   GenericInstanceRef get ref => _ref;
   GenericInstanceRef _ref;
 
+  int get offset => _offset;
+  int _offset;
+
+  int get count => _count;
+  int _count;
+
+  bool get isGrouping => _isGrouping;
+  bool _isGrouping;
+
   bool treeInitializeStarted = false;
   bool treeInitializeComplete = false;
 
@@ -726,6 +773,25 @@ class Variable extends TreeNode<Variable> {
 
   Object get value => ref?.value;
 
+  int get childCount {
+    if (isGrouping) {
+      return count;
+    }
+
+    final value = this.value;
+    if (value is InstanceRef) {
+      if (value.kind == InstanceKind.kList) {
+        return value.length;
+      } else if (value.kind == InstanceKind.kMap) {
+        return value.length;
+      } else if (value.kind != null && value.kind.endsWith('List')) {
+        return value.length;
+      }
+    }
+
+    return 0;
+  }
+
   // TODO(kenz): add custom display for lists with more than 100 elements
   String get displayValue {
     if (text != null) {
diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index ba97a38ffe1..389d864ef1d 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -45,7 +45,9 @@ class Variables extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      v.children.forEach(buildVariablesTree);
+      v.children.forEach(
+        (v) => buildVariablesTree(v, offset: v.offset, count: v.count),
+      );
     }
   }
 }
diff --git a/packages/devtools_app/lib/src/utils.dart b/packages/devtools_app/lib/src/utils.dart
index 1f6e82cad88..27ef3a6c77d 100644
--- a/packages/devtools_app/lib/src/utils.dart
+++ b/packages/devtools_app/lib/src/utils.dart
@@ -186,7 +186,13 @@ T nullSafeMax<T extends num>(T a, T b) {
   return max<T>(a, b);
 }
 
-int log2(num x) => (log(x) / log(2)).floor();
+double logBase(num x, num base) {
+  return log(x) / log(base);
+}
+
+int log2(num x) => (logBase(x, 2)).floor();
+
+int roundToNearestPow10(num x) => pow(10, logBase(x, 10).ceil()).floor();
 
 String isolateName(IsolateRef ref) {
   // analysis_server.dart.snapshot$main
diff --git a/packages/devtools_app/lib/src/vm_service_wrapper.dart b/packages/devtools_app/lib/src/vm_service_wrapper.dart
index 49a3d181eed..5230ba9dfeb 100644
--- a/packages/devtools_app/lib/src/vm_service_wrapper.dart
+++ b/packages/devtools_app/lib/src/vm_service_wrapper.dart
@@ -401,7 +401,10 @@ class VmServiceWrapper implements VmService {
     int offset,
     int count,
   }) {
-    return trackFuture('getObject', _vmService.getObject(isolateId, objectId));
+    return trackFuture(
+        'getObject',
+        _vmService.getObject(isolateId, objectId,
+            offset: offset, count: count));
   }
 
   @override
diff --git a/packages/devtools_app/macos/Runner.xcodeproj/project.pbxproj b/packages/devtools_app/macos/Runner.xcodeproj/project.pbxproj
index a4d00fa9693..bc03301f8ac 100644
--- a/packages/devtools_app/macos/Runner.xcodeproj/project.pbxproj
+++ b/packages/devtools_app/macos/Runner.xcodeproj/project.pbxproj
@@ -308,9 +308,14 @@
 			files = (
 			);
 			inputPaths = (
+				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
+				"${BUILT_PRODUCTS_DIR}/file_selector_macos/file_selector_macos.framework",
+				"${BUILT_PRODUCTS_DIR}/url_launcher_macos/url_launcher_macos.framework",
 			);
 			name = "[CP] Embed Pods Frameworks";
 			outputPaths = (
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/file_selector_macos.framework",
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/url_launcher_macos.framework",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
diff --git a/packages/devtools_app/test/utils_test.dart b/packages/devtools_app/test/utils_test.dart
index 63e7bb02084..6a22316ba94 100644
--- a/packages/devtools_app/test/utils_test.dart
+++ b/packages/devtools_app/test/utils_test.dart
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-
 import 'package:devtools_app/src/utils.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
@@ -109,6 +108,16 @@ void main() {
       expect(log2(4), equals(2));
     });
 
+    test('roundToNearestPow10', () {
+      expect(roundToNearestPow10(0.1), equals(1));
+      expect(roundToNearestPow10(1), equals(1));
+      expect(roundToNearestPow10(2), equals(10));
+      expect(roundToNearestPow10(10), equals(10));
+      expect(roundToNearestPow10(11), equals(100));
+      expect(roundToNearestPow10(189), equals(1000));
+      expect(roundToNearestPow10(6581), equals(10000));
+    });
+
     test('executeWithDelay', () async {
       const delayMs = 500;
       int n = 1;

From ae2619caf8dfd88cb862d72caab0d4be4e6310ea Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Thu, 28 Oct 2021 17:08:57 -0700
Subject: [PATCH 02/19] List and maps working

---
 .../lib/src/debugger/debugger_model.dart      | 59 +++++++++++--------
 .../lib/src/debugger/variables.dart           |  3 +-
 2 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 38fb47c667f..4bbfa64a674 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -382,29 +382,37 @@ Future<void> buildVariablesTree(
       }
     }
   }
-  if (instanceRef != null && serviceManager.service != null) {
+
+  if (variable.childCount > Variable.MAX_CHILDREN_IN_GROUPING) {
+    final numChildrenInGrouping = variable.childCount >=
+            Variable.MAX_CHILDREN_IN_GROUPING *
+                Variable.MAX_CHILDREN_IN_GROUPING
+        ? (roundToNearestPow10(variable.childCount) /
+                Variable.MAX_CHILDREN_IN_GROUPING)
+            .floor()
+        : Variable.MAX_CHILDREN_IN_GROUPING;
+
+    var offset = 0;
+    while (offset + numChildrenInGrouping < variable.childCount) {
+      variable.addChild(
+        Variable.grouping(variable.ref,
+            offset: offset, count: numChildrenInGrouping),
+      );
+      offset += numChildrenInGrouping;
+    }
+    variable.addChild(
+      Variable.grouping(variable.ref,
+          offset: offset, count: variable.childCount - offset),
+    );
+  } else if (instanceRef != null && serviceManager.service != null) {
     try {
       final dynamic result = await serviceManager.service.getObject(
           variable.ref.isolateRef.id, instanceRef.id,
           offset: offset, count: count);
       if (result is Instance) {
         if (result.associations != null) {
-          if (variable.childCount > 50) {
-            var offset = 0;
-            while (offset + 50 < variable.childCount) {
-              variable.addChild(
-                Variable.grouping(variable.ref, offset: offset, count: 50),
-              );
-              offset = offset + 50;
-            }
-            final remainder = variable.childCount - offset;
-            final childVar = Variable.grouping(variable.ref,
-                offset: offset, count: remainder);
-            variable.addChild(childVar);
-          } else {
-            variable.addAllChildren(
-                _createVariablesForAssociations(result, isolateRef));
-          }
+          variable.addAllChildren(
+              _createVariablesForAssociations(result, isolateRef));
         } else if (result.elements != null) {
           // this is for a list
           variable
@@ -546,8 +554,9 @@ List<Variable> _createVariablesForAssociations(
       value: association.value,
       isolateRef: isolateRef,
     );
+    final entryNum = instance.offset == null ? i : i + instance.offset;
     variables.add(
-      Variable.text('[Entry $i]')
+      Variable.text('[Entry $entryNum]')
         ..addChild(key)
         ..addChild(value),
     );
@@ -622,9 +631,10 @@ List<Variable> _createVariablesForBytes(
   }
 
   for (int i = 0; i < result.length; i++) {
+    final name = instance.offset == null ? i : i + instance.offset;
     variables.add(
       Variable.fromValue(
-        name: '[$i]',
+        name: '[$name]',
         value: result[i],
         isolateRef: isolateRef,
       ),
@@ -639,9 +649,10 @@ List<Variable> _createVariablesForElements(
 ) {
   final variables = <Variable>[];
   for (int i = 0; i < instance.elements.length; i++) {
+    final name = instance.offset == null ? i : i + instance.offset;
     variables.add(
       Variable.fromValue(
-        name: '[$i]',
+        name: '[$name]',
         value: instance.elements[i],
         isolateRef: isolateRef,
       ),
@@ -733,13 +744,15 @@ class Variable extends TreeNode<Variable> {
     return Variable._(
       null,
       ref,
-      '[$offset - ${offset + count}]',
+      '[$offset ... ${offset + count - 1}]',
       offset: offset,
       count: count,
       isGrouping: true,
     );
   }
 
+  static const MAX_CHILDREN_IN_GROUPING = 100;
+
   final String text;
   final String name;
   GenericInstanceRef get ref => _ref;
@@ -759,8 +772,8 @@ class Variable extends TreeNode<Variable> {
 
   @override
   bool get isExpandable {
-    if (treeInitializeComplete || children.isNotEmpty) {
-      return children.isNotEmpty;
+    if (treeInitializeComplete || children.isNotEmpty || childCount > 0) {
+      return children.isNotEmpty || childCount > 0;
     }
     final diagnostic = ref.diagnostic;
     if (diagnostic != null &&
diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index 389d864ef1d..47a748da699 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -46,7 +46,8 @@ class Variables extends StatelessWidget {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
       v.children.forEach(
-        (v) => buildVariablesTree(v, offset: v.offset, count: v.count),
+        (child) =>
+            buildVariablesTree(child, offset: child.offset, count: child.count),
       );
     }
   }

From 9ad13b77c2373069c98e7765958bfd1793acf179 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 29 Oct 2021 13:13:26 -0700
Subject: [PATCH 03/19] Committing to switch branches

---
 packages/devtools_app/lib/src/console_service.dart  |  1 +
 .../devtools_app/lib/src/debugger/codeview.dart     |  3 ++-
 .../lib/src/debugger/debugger_controller.dart       |  5 +++--
 .../lib/src/debugger/debugger_model.dart            |  1 -
 .../devtools_app/lib/src/debugger/variables.dart    | 13 +++++++++++--
 .../devtools_app/lib/src/inspector/diagnostics.dart |  1 +
 6 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/packages/devtools_app/lib/src/console_service.dart b/packages/devtools_app/lib/src/console_service.dart
index bd6be18ea57..42d5f7a8cec 100644
--- a/packages/devtools_app/lib/src/console_service.dart
+++ b/packages/devtools_app/lib/src/console_service.dart
@@ -81,6 +81,7 @@ class ConsoleService extends Disposer {
       isolateRef: isolateRef,
     );
     // TODO(jacobr): fix out of order issues by tracking raw order.
+    print('build variable in console.');
     await buildVariablesTree(variable, expandAll: expandAll);
     if (expandAll) {
       variable.expandCascading();
diff --git a/packages/devtools_app/lib/src/debugger/codeview.dart b/packages/devtools_app/lib/src/debugger/codeview.dart
index 7d102dc2fd4..51143921a8a 100644
--- a/packages/devtools_app/lib/src/debugger/codeview.dart
+++ b/packages/devtools_app/lib/src/debugger/codeview.dart
@@ -787,7 +787,8 @@ class _LineItemState extends State<LineItem> {
             value: response,
             isolateRef: isolateRef,
           );
-          await buildVariablesTree(variable);
+          print('===== ON HOVER, BUILD VARIABLE.');
+          await buildVariablesTree(variable, offset: 0, count: 0);
           if (_hasMouseExited) return;
           _hoverCard?.remove();
           _hoverCard = HoverCard.fromHoverEvent(
diff --git a/packages/devtools_app/lib/src/debugger/debugger_controller.dart b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
index f5a1a62baa5..75e34472430 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_controller.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
@@ -763,8 +763,9 @@ class DebuggerController extends DisposableController
     // Collecting frames for Dart web applications can be slow. At the potential
     // cost of a flicker in the stack view, display only the top frame
     // initially.
-    // Note: Should find a better solution for this.
-    //Currently, this means we fetch all variable objects twice. (Once here, and once in _getFullStack)
+    // TODO(elliette): Find a better solution for this. Currently, this means
+    // we fetch all variable objects twice (once in _getFullStack and once in
+    // in_createStackFrameWithLocation).
     if (await serviceManager.connectedApp.isDartWebApp) {
       _populateFrameInfo(
         [
diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 4bbfa64a674..689fed836ec 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -414,7 +414,6 @@ Future<void> buildVariablesTree(
           variable.addAllChildren(
               _createVariablesForAssociations(result, isolateRef));
         } else if (result.elements != null) {
-          // this is for a list
           variable
               .addAllChildren(_createVariablesForElements(result, isolateRef));
         } else if (result.bytes != null) {
diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index 47a748da699..876da8e12ff 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -45,6 +45,7 @@ class Variables extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
+      print('===== A =====');
       v.children.forEach(
         (child) =>
             buildVariablesTree(child, offset: child.offset, count: child.count),
@@ -75,7 +76,11 @@ class VariablesList extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      v.children.forEach(buildVariablesTree);
+      print('====== B =====');
+      v.children.forEach(
+        (child) =>
+            buildVariablesTree(child, offset: child.offset, count: child.count),
+      );
     }
   }
 }
@@ -114,7 +119,11 @@ class ExpandableVariable extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      v.children.forEach(buildVariablesTree);
+      print('======= C ======');
+      v.children.forEach(
+        (child) =>
+            buildVariablesTree(child, offset: child.offset, count: child.count),
+      );
     }
   }
 }
diff --git a/packages/devtools_app/lib/src/inspector/diagnostics.dart b/packages/devtools_app/lib/src/inspector/diagnostics.dart
index 009c507d9d2..64182ed020a 100644
--- a/packages/devtools_app/lib/src/inspector/diagnostics.dart
+++ b/packages/devtools_app/lib/src/inspector/diagnostics.dart
@@ -125,6 +125,7 @@ class DiagnosticsNodeDescription extends StatelessWidget {
           isolateRef: serviceManager.inspectorService.isolateRef,
           diagnostic: diagnostic,
         );
+        print('------ build variable in diagnostics? -----');
         await buildVariablesTree(variable);
         for (var child in variable.children) {
           await buildVariablesTree(child);

From 1b9a3499f1d4ad7a96589a4bb63d40279500b46e Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 1 Nov 2021 09:52:22 -0700
Subject: [PATCH 04/19] Offset/count defaults to 0

---
 .../lib/src/debugger/codeview.dart             |  2 +-
 .../lib/src/debugger/debugger_controller.dart  |  2 +-
 .../lib/src/debugger/debugger_model.dart       | 16 ++++++++--------
 .../lib/src/debugger/variables.dart            | 18 +++---------------
 4 files changed, 13 insertions(+), 25 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/codeview.dart b/packages/devtools_app/lib/src/debugger/codeview.dart
index 51143921a8a..8364602987b 100644
--- a/packages/devtools_app/lib/src/debugger/codeview.dart
+++ b/packages/devtools_app/lib/src/debugger/codeview.dart
@@ -788,7 +788,7 @@ class _LineItemState extends State<LineItem> {
             isolateRef: isolateRef,
           );
           print('===== ON HOVER, BUILD VARIABLE.');
-          await buildVariablesTree(variable, offset: 0, count: 0);
+          await buildVariablesTree(variable);
           if (_hasMouseExited) return;
           _hoverCard?.remove();
           _hoverCard = HoverCard.fromHoverEvent(
diff --git a/packages/devtools_app/lib/src/debugger/debugger_controller.dart b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
index 75e34472430..875665cc642 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_controller.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_controller.dart
@@ -952,7 +952,7 @@ class DebuggerController extends DisposableController
     final variables =
         frame.vars.map((v) => Variable.create(v, isolateRef)).toList();
     variables
-      ..forEach((v) => buildVariablesTree(v, offset: 0, count: 0))
+      ..forEach(buildVariablesTree)
       ..sort((a, b) => sortFieldsByName(a.name, b.name));
     return variables;
   }
diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 689fed836ec..6a930e09d2d 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -334,8 +334,6 @@ Future<void> addExpandableChildren(
 Future<void> buildVariablesTree(
   Variable variable, {
   bool expandAll = false,
-  int offset,
-  int count,
 }) async {
   final ref = variable.ref;
   if (!variable.isExpandable || variable.treeInitializeStarted || ref == null)
@@ -392,23 +390,25 @@ Future<void> buildVariablesTree(
             .floor()
         : Variable.MAX_CHILDREN_IN_GROUPING;
 
-    var offset = 0;
-    while (offset + numChildrenInGrouping < variable.childCount) {
+    var index = 0;
+    while (index + numChildrenInGrouping < variable.childCount) {
       variable.addChild(
         Variable.grouping(variable.ref,
-            offset: offset, count: numChildrenInGrouping),
+            offset: index + (variable.offset ?? 0),
+            count: numChildrenInGrouping),
       );
-      offset += numChildrenInGrouping;
+      index += numChildrenInGrouping;
     }
     variable.addChild(
       Variable.grouping(variable.ref,
-          offset: offset, count: variable.childCount - offset),
+          offset: index + (variable.offset ?? 0),
+          count: variable.childCount - index),
     );
   } else if (instanceRef != null && serviceManager.service != null) {
     try {
       final dynamic result = await serviceManager.service.getObject(
           variable.ref.isolateRef.id, instanceRef.id,
-          offset: offset, count: count);
+          offset: variable.offset ?? 0, count: variable.count ?? 0);
       if (result is Instance) {
         if (result.associations != null) {
           variable.addAllChildren(
diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index 876da8e12ff..ba97a38ffe1 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -45,11 +45,7 @@ class Variables extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      print('===== A =====');
-      v.children.forEach(
-        (child) =>
-            buildVariablesTree(child, offset: child.offset, count: child.count),
-      );
+      v.children.forEach(buildVariablesTree);
     }
   }
 }
@@ -76,11 +72,7 @@ class VariablesList extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      print('====== B =====');
-      v.children.forEach(
-        (child) =>
-            buildVariablesTree(child, offset: child.offset, count: child.count),
-      );
+      v.children.forEach(buildVariablesTree);
     }
   }
 }
@@ -119,11 +111,7 @@ class ExpandableVariable extends StatelessWidget {
   void onItemPressed(Variable v, DebuggerController controller) {
     // On expansion, lazily build the variables tree for performance reasons.
     if (v.isExpanded) {
-      print('======= C ======');
-      v.children.forEach(
-        (child) =>
-            buildVariablesTree(child, offset: child.offset, count: child.count),
-      );
+      v.children.forEach(buildVariablesTree);
     }
   }
 }

From b83f2f71bc291319a7834fb28b77ed28a87edb14 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 2 Nov 2021 15:36:43 -0700
Subject: [PATCH 05/19] Add in basic retry logic

---
 .../lib/src/debugger/codeview.dart            |  1 -
 .../lib/src/debugger/debugger_model.dart      | 22 +++++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/codeview.dart b/packages/devtools_app/lib/src/debugger/codeview.dart
index 8364602987b..7d102dc2fd4 100644
--- a/packages/devtools_app/lib/src/debugger/codeview.dart
+++ b/packages/devtools_app/lib/src/debugger/codeview.dart
@@ -787,7 +787,6 @@ class _LineItemState extends State<LineItem> {
             value: response,
             isolateRef: isolateRef,
           );
-          print('===== ON HOVER, BUILD VARIABLE.');
           await buildVariablesTree(variable);
           if (_hasMouseExited) return;
           _hoverCard?.remove();
diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 6a930e09d2d..93b3da240d4 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -406,9 +406,9 @@ Future<void> buildVariablesTree(
     );
   } else if (instanceRef != null && serviceManager.service != null) {
     try {
-      final dynamic result = await serviceManager.service.getObject(
+      final dynamic result = await _getObjectWithRetry(
           variable.ref.isolateRef.id, instanceRef.id,
-          offset: variable.offset ?? 0, count: variable.count ?? 0);
+          offset: variable.offset, count: variable.count);
       if (result is Instance) {
         if (result.associations != null) {
           variable.addAllChildren(
@@ -500,6 +500,24 @@ Future<void> buildVariablesTree(
   variable.treeInitializeComplete = true;
 }
 
+Future<Obj> _getObjectWithRetry(
+  String isolateId,
+  String objectId, {
+  int offset,
+  int count,
+}) async {
+  try {
+    final dynamic result = await serviceManager.service
+        .getObject(isolateId, objectId, offset: offset ?? 0, count: count ?? 0);
+    return result;
+  } catch (e) {
+    // TODO(elliette): Remove once https://github.com/dart-lang/webdev/issues/1439 is landed. This fixes
+    final dynamic result =
+        await serviceManager.service.getObject(isolateId, objectId);
+    return result;
+  }
+}
+
 Future<Variable> _buildVariable(
   RemoteDiagnosticsNode diagnostic,
   ObjectGroup inspectorService,

From c10ceafa079778b36b421222ad3dee2edbf97723 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Thu, 11 Nov 2021 11:11:15 -0800
Subject: [PATCH 06/19] Polish

---
 .../devtools_app/lib/src/console_service.dart |  1 -
 .../lib/src/debugger/debugger_model.dart      | 83 +++++++++----------
 .../lib/src/inspector/diagnostics.dart        |  1 -
 3 files changed, 39 insertions(+), 46 deletions(-)

diff --git a/packages/devtools_app/lib/src/console_service.dart b/packages/devtools_app/lib/src/console_service.dart
index 42d5f7a8cec..bd6be18ea57 100644
--- a/packages/devtools_app/lib/src/console_service.dart
+++ b/packages/devtools_app/lib/src/console_service.dart
@@ -81,7 +81,6 @@ class ConsoleService extends Disposer {
       isolateRef: isolateRef,
     );
     // TODO(jacobr): fix out of order issues by tracking raw order.
-    print('build variable in console.');
     await buildVariablesTree(variable, expandAll: expandAll);
     if (expandAll) {
       variable.expandCascading();
diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 93b3da240d4..389d70348dd 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -406,9 +406,8 @@ Future<void> buildVariablesTree(
     );
   } else if (instanceRef != null && serviceManager.service != null) {
     try {
-      final dynamic result = await _getObjectWithRetry(
-          variable.ref.isolateRef.id, instanceRef.id,
-          offset: variable.offset, count: variable.count);
+      final dynamic result =
+          await _getObjectWithRetry(instanceRef.id, variable);
       if (result is Instance) {
         if (result.associations != null) {
           variable.addAllChildren(
@@ -500,20 +499,21 @@ Future<void> buildVariablesTree(
   variable.treeInitializeComplete = true;
 }
 
+// TODO(elliette): Remove once the fix for dart-lang/webdev/issues/1439
+// is landed. This works around a bug in DWDS where an error is thrown if
+// `getObject` is called with offset/count for an object that has no length.
 Future<Obj> _getObjectWithRetry(
-  String isolateId,
-  String objectId, {
-  int offset,
-  int count,
-}) async {
+  String objectId,
+  Variable variable,
+) async {
   try {
-    final dynamic result = await serviceManager.service
-        .getObject(isolateId, objectId, offset: offset ?? 0, count: count ?? 0);
+    final dynamic result = await serviceManager.service.getObject(
+        variable.ref.isolateRef.id, objectId,
+        offset: variable.offset, count: variable.childCount);
     return result;
   } catch (e) {
-    // TODO(elliette): Remove once https://github.com/dart-lang/webdev/issues/1439 is landed. This fixes
-    final dynamic result =
-        await serviceManager.service.getObject(isolateId, objectId);
+    final dynamic result = await serviceManager.service
+        .getObject(variable.ref.isolateRef.id, objectId);
     return result;
   }
 }
@@ -703,12 +703,10 @@ List<Variable> _createVariablesForFields(
 // TODO(jacobr): consider a new class name. This class is more just the data
 // model for a tree of Dart objects with properties rather than a "Variable".
 class Variable extends TreeNode<Variable> {
-  Variable._(this.name, ref, this.text,
-      {int offset, int count, bool isGrouping = false})
+  Variable._(this.name, ref, this.text, {int offset, int childCount})
       : _ref = ref,
         _offset = offset,
-        _count = count,
-        _isGrouping = isGrouping {
+        _childCount = childCount {
     indentChildren = ref?.diagnostic?.style != DiagnosticsTreeStyle.flat;
   }
 
@@ -761,10 +759,9 @@ class Variable extends TreeNode<Variable> {
     return Variable._(
       null,
       ref,
-      '[$offset ... ${offset + count - 1}]',
+      '[$offset - ${offset + count - 1}]',
       offset: offset,
-      count: count,
-      isGrouping: true,
+      childCount: count,
     );
   }
 
@@ -775,14 +772,31 @@ class Variable extends TreeNode<Variable> {
   GenericInstanceRef get ref => _ref;
   GenericInstanceRef _ref;
 
-  int get offset => _offset;
+  int get offset {
+    if (_offset != null) return _offset;
+    return 0;
+  }
+
   int _offset;
 
-  int get count => _count;
-  int _count;
+  int get childCount {
+    if (_childCount != null) return _childCount;
+
+    final value = this.value;
+    if (value is InstanceRef) {
+      if (value.kind == InstanceKind.kList) {
+        return value.length ?? 0;
+      } else if (value.kind == InstanceKind.kMap) {
+        return value.length ?? 0;
+      } else if (value.kind != null && value.kind.endsWith('List')) {
+        return value.length ?? 0;
+      }
+    }
+
+    return 0;
+  }
 
-  bool get isGrouping => _isGrouping;
-  bool _isGrouping;
+  int _childCount;
 
   bool treeInitializeStarted = false;
   bool treeInitializeComplete = false;
@@ -803,25 +817,6 @@ class Variable extends TreeNode<Variable> {
 
   Object get value => ref?.value;
 
-  int get childCount {
-    if (isGrouping) {
-      return count;
-    }
-
-    final value = this.value;
-    if (value is InstanceRef) {
-      if (value.kind == InstanceKind.kList) {
-        return value.length;
-      } else if (value.kind == InstanceKind.kMap) {
-        return value.length;
-      } else if (value.kind != null && value.kind.endsWith('List')) {
-        return value.length;
-      }
-    }
-
-    return 0;
-  }
-
   // TODO(kenz): add custom display for lists with more than 100 elements
   String get displayValue {
     if (text != null) {
diff --git a/packages/devtools_app/lib/src/inspector/diagnostics.dart b/packages/devtools_app/lib/src/inspector/diagnostics.dart
index 64182ed020a..009c507d9d2 100644
--- a/packages/devtools_app/lib/src/inspector/diagnostics.dart
+++ b/packages/devtools_app/lib/src/inspector/diagnostics.dart
@@ -125,7 +125,6 @@ class DiagnosticsNodeDescription extends StatelessWidget {
           isolateRef: serviceManager.inspectorService.isolateRef,
           diagnostic: diagnostic,
         );
-        print('------ build variable in diagnostics? -----');
         await buildVariablesTree(variable);
         for (var child in variable.children) {
           await buildVariablesTree(child);

From 75496fd1d1a2ec4f66f68f13fad8f179f16c2877 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Thu, 11 Nov 2021 16:49:20 -0800
Subject: [PATCH 07/19] Added tests

---
 .../test/debugger_screen_test.dart            | 376 +++++++++++++-----
 packages/devtools_test/lib/mocks.dart         |  12 +
 2 files changed, 278 insertions(+), 110 deletions(-)

diff --git a/packages/devtools_app/test/debugger_screen_test.dart b/packages/devtools_app/test/debugger_screen_test.dart
index a677dc3f43d..9dc77e5354d 100644
--- a/packages/devtools_app/test/debugger_screen_test.dart
+++ b/packages/devtools_app/test/debugger_screen_test.dart
@@ -439,54 +439,185 @@ void main() {
       expect(find.text('<async break>'), findsOneWidget);
     });
 
-    testWidgetsWithWindowSize(
-        'Variables shows items', const Size(1000.0, 4000.0),
-        (WidgetTester tester) async {
-      when(debuggerController.variables)
-          .thenReturn(ValueNotifier(testVariables));
-      await pumpDebuggerScreen(tester, debuggerController);
-      expect(find.text('Variables'), findsOneWidget);
+    group('Variables', () {
+      setUp(() {
+        resetRef();
+        resetRoot();
+      });
 
-      final listFinder = find.selectableText('Root 1: _GrowableList (2 items)');
+      testWidgetsWithWindowSize(
+          'Variables shows items', const Size(1000.0, 4000.0),
+          (WidgetTester tester) async {
+        when(debuggerController.variables).thenReturn(
+          ValueNotifier(
+            [
+              buildListVariable(),
+              buildMapVariable(),
+              buildStringVariable('test str'),
+              buildBooleanVariable(true),
+            ],
+          ),
+        );
+        await pumpDebuggerScreen(tester, debuggerController);
+        expect(find.text('Variables'), findsOneWidget);
 
-      // expect a tooltip for the list value
-      expect(
-        find.byTooltip('_GrowableList (2 items)'),
-        findsOneWidget,
-      );
+        final listFinder =
+            find.selectableText('Root 1: _GrowableList (2 items)');
 
-      final mapFinder = find
-          .selectableTextContaining('Root 2: _InternalLinkedHashmap (2 items)');
-      final mapElement1Finder = find.selectableTextContaining("['key1']: 1.0");
-      final mapElement2Finder = find.selectableTextContaining("['key2']: 1.1");
+        // expect a tooltip for the list value
+        expect(
+          find.byTooltip('_GrowableList (2 items)'),
+          findsOneWidget,
+        );
 
-      expect(listFinder, findsOneWidget);
-      expect(mapFinder, findsOneWidget);
-      expect(
-        find.selectableTextContaining("Root 3: 'test str...'"),
-        findsOneWidget,
-      );
-      expect(
-        find.selectableTextContaining('Root 4: true'),
-        findsOneWidget,
+        final mapFinder = find.selectableTextContaining(
+            'Root 2: _InternalLinkedHashmap (2 items)');
+        final mapElement1Finder =
+            find.selectableTextContaining("['key1']: 1.0");
+        final mapElement2Finder =
+            find.selectableTextContaining("['key2']: 2.0");
+
+        expect(listFinder, findsOneWidget);
+        expect(mapFinder, findsOneWidget);
+        expect(
+          find.selectableTextContaining("Root 3: 'test str...'"),
+          findsOneWidget,
+        );
+        expect(
+          find.selectableTextContaining('Root 4: true'),
+          findsOneWidget,
+        );
+
+        // Expand list.
+        expect(find.selectableTextContaining('0: 3'), findsNothing);
+        expect(find.selectableTextContaining('1: 4'), findsNothing);
+
+        await tester.tap(listFinder);
+        await tester.pump();
+        expect(find.selectableTextContaining('0: 0'), findsOneWidget);
+        expect(find.selectableTextContaining('1: 1'), findsOneWidget);
+
+        // Expand map.
+        expect(mapElement1Finder, findsNothing);
+        expect(mapElement2Finder, findsNothing);
+        await tester.tap(mapFinder);
+        await tester.pump();
+        expect(mapElement1Finder, findsOneWidget);
+        expect(mapElement2Finder, findsOneWidget);
+      });
+    });
+
+    testWidgetsWithWindowSize('Children in large list variables are grouped',
+        const Size(1000.0, 4000.0), (WidgetTester tester) async {
+      final list = buildParentListVariable(length: 380250);
+      await buildVariablesTree(list);
+      when(debuggerController.variables).thenReturn(
+        ValueNotifier(
+          [
+            list,
+          ],
+        ),
       );
+      await pumpDebuggerScreen(tester, debuggerController);
 
-      // Expand list.
-      expect(find.selectableTextContaining('0: 3'), findsNothing);
-      expect(find.selectableTextContaining('1: 4'), findsNothing);
+      final listFinder =
+          find.selectableText('Root 1: _GrowableList (380,250 items)');
+      final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
+      final group10000To19999Finder =
+          find.selectableTextContaining('[10000 - 19999]');
+      final group370000To379999Finder =
+          find.selectableTextContaining('[370000 - 379999]');
+      final group380000To380249Finder =
+          find.selectableTextContaining('[380000 - 380249]');
+
+      final group370000To370099Finder =
+          find.selectableTextContaining('[370000 - 370099]');
+      final group370100To370199Finder =
+          find.selectableTextContaining('[370100 - 370199]');
+      final group370200To370299Finder =
+          find.selectableTextContaining('[370200 - 370299]');
+
+      // Initially list is not expanded.
+      expect(listFinder, findsOneWidget);
+      expect(group0To9999Finder, findsNothing);
+      expect(group10000To19999Finder, findsNothing);
+      expect(group370000To379999Finder, findsNothing);
+      expect(group380000To380249Finder, findsNothing);
 
+      // Expand list.
       await tester.tap(listFinder);
       await tester.pump();
-      expect(find.selectableTextContaining('0: 3'), findsOneWidget);
-      expect(find.selectableTextContaining('1: 4'), findsOneWidget);
+      expect(group0To9999Finder, findsOneWidget);
+      expect(group10000To19999Finder, findsOneWidget);
+      expect(group370000To379999Finder, findsOneWidget);
+      expect(group380000To380249Finder, findsOneWidget);
+
+      // Initially group [370000 - 379999] is not expanded.
+      expect(group370000To370099Finder, findsNothing);
+      expect(group370100To370199Finder, findsNothing);
+      expect(group370200To370299Finder, findsNothing);
+
+      // Expand group [370000 - 379999].
+      await tester.tap(group370000To379999Finder);
+      await tester.pump();
+      expect(group370000To370099Finder, findsOneWidget);
+      expect(group370100To370199Finder, findsOneWidget);
+      expect(group370200To370299Finder, findsOneWidget);
+    });
+
+    testWidgetsWithWindowSize('Children in large map variables are grouped',
+        const Size(1000.0, 4000.0), (WidgetTester tester) async {
+      final map = buildParentMapVariable(length: 243621);
+      await buildVariablesTree(map);
+      when(debuggerController.variables).thenReturn(
+        ValueNotifier(
+          [
+            map,
+          ],
+        ),
+      );
+      await pumpDebuggerScreen(tester, debuggerController);
+
+      final listFinder =
+          find.selectableText('Root 1: _InternalLinkedHashmap (243,621 items)');
+      final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
+      final group10000To19999Finder =
+          find.selectableTextContaining('[10000 - 19999]');
+      final group230000To239999Finder =
+          find.selectableTextContaining('[230000 - 239999]');
+      final group240000To243620Finder =
+          find.selectableTextContaining('[240000 - 243620]');
+
+      final group0To99Finder = find.selectableTextContaining('[0 - 99]');
+      final group100To199Finder = find.selectableTextContaining('[100 - 199]');
+      final group200To299Finder = find.selectableTextContaining('[200 - 299]');
+
+      // Initially map is not expanded.
+      expect(listFinder, findsOneWidget);
+      expect(group0To9999Finder, findsNothing);
+      expect(group10000To19999Finder, findsNothing);
+      expect(group230000To239999Finder, findsNothing);
+      expect(group240000To243620Finder, findsNothing);
 
       // Expand map.
-      expect(mapElement1Finder, findsNothing);
-      expect(mapElement2Finder, findsNothing);
-      await tester.tap(mapFinder);
+      await tester.tap(listFinder);
+      await tester.pump();
+      expect(group0To9999Finder, findsOneWidget);
+      expect(group10000To19999Finder, findsOneWidget);
+      expect(group230000To239999Finder, findsOneWidget);
+      expect(group240000To243620Finder, findsOneWidget);
+
+      // Initially group [0 - 9999] is not expanded.
+      expect(group0To99Finder, findsNothing);
+      expect(group100To199Finder, findsNothing);
+      expect(group200To299Finder, findsNothing);
+
+      // Expand group [0 - 9999].
+      await tester.tap(group0To9999Finder);
       await tester.pump();
-      expect(mapElement1Finder, findsOneWidget);
-      expect(mapElement2Finder, findsOneWidget);
+      expect(group0To99Finder, findsOneWidget);
+      expect(group100To199Finder, findsOneWidget);
+      expect(group200To299Finder, findsOneWidget);
     });
 
     WidgetPredicate createDebuggerButtonPredicate(String title) {
@@ -669,19 +800,41 @@ final isolateRef = IsolateRef(
   isSystemIsolate: false,
 );
 
-final testVariables = [
-  Variable.create(
+int refNumber = 0;
+
+String incrementRef() {
+  refNumber = refNumber + 1;
+  return 'ref$refNumber';
+}
+
+void resetRef() {
+  refNumber = 0;
+}
+
+int rootNumber = 0;
+
+String incrementRoot() {
+  rootNumber = rootNumber + 1;
+  return 'Root $rootNumber';
+}
+
+void resetRoot() {
+  rootNumber = 0;
+}
+
+Variable buildParentListVariable({int length = 2}) {
+  return Variable.create(
     BoundVariable(
-      name: 'Root 1',
+      name: incrementRoot(),
       value: InstanceRef(
-        id: 'ref1',
+        id: incrementRef(),
         kind: InstanceKind.kList,
         classRef: ClassRef(
           name: '_GrowableList',
-          id: 'ref2',
+          id: incrementRef(),
           library: libraryRef,
         ),
-        length: 2,
+        length: length,
         identityHashCode: null,
       ),
       declarationTokenPos: null,
@@ -689,34 +842,23 @@ final testVariables = [
       scopeStartTokenPos: null,
     ),
     isolateRef,
-  )..addAllChildren([
-      Variable.create(
-        BoundVariable(
-          name: '0',
-          value: InstanceRef(
-            id: 'ref3',
-            kind: InstanceKind.kInt,
-            classRef:
-                ClassRef(name: 'Integer', id: 'ref4', library: libraryRef),
-            valueAsString: '3',
-            valueAsStringIsTruncated: false,
-            identityHashCode: null,
-          ),
-          declarationTokenPos: null,
-          scopeEndTokenPos: null,
-          scopeStartTokenPos: null,
-        ),
-        isolateRef,
-      ),
+  );
+}
+
+Variable buildListVariable({int length = 2}) {
+  final listVariable = buildParentListVariable(length: length);
+
+  for (int i = 0; i < length; i++) {
+    listVariable.addChild(
       Variable.create(
         BoundVariable(
-          name: '1',
+          name: '$i',
           value: InstanceRef(
-            id: 'ref5',
+            id: incrementRef(),
             kind: InstanceKind.kInt,
-            classRef:
-                ClassRef(name: 'Integer', id: 'ref6', library: libraryRef),
-            valueAsString: '4',
+            classRef: ClassRef(
+                name: 'Integer', id: incrementRef(), library: libraryRef),
+            valueAsString: '$i',
             valueAsStringIsTruncated: false,
             identityHashCode: null,
           ),
@@ -726,16 +868,24 @@ final testVariables = [
         ),
         isolateRef,
       ),
-    ]),
-  Variable.create(
+    );
+  }
+
+  return listVariable;
+}
+
+Variable buildParentMapVariable({int length = 2}) {
+  return Variable.create(
     BoundVariable(
-      name: 'Root 2',
+      name: incrementRoot(),
       value: InstanceRef(
-        id: 'ref7',
+        id: incrementRef(),
         kind: InstanceKind.kMap,
         classRef: ClassRef(
-            name: '_InternalLinkedHashmap', id: 'ref8', library: libraryRef),
-        length: 2,
+            name: '_InternalLinkedHashmap',
+            id: incrementRef(),
+            library: libraryRef),
+        length: length,
         identityHashCode: null,
       ),
       declarationTokenPos: null,
@@ -743,34 +893,23 @@ final testVariables = [
       scopeStartTokenPos: null,
     ),
     isolateRef,
-  )..addAllChildren([
-      Variable.create(
-        BoundVariable(
-          name: "['key1']",
-          value: InstanceRef(
-            id: 'ref9',
-            kind: InstanceKind.kDouble,
-            classRef:
-                ClassRef(name: 'Double', id: 'ref10', library: libraryRef),
-            valueAsString: '1.0',
-            valueAsStringIsTruncated: false,
-            identityHashCode: null,
-          ),
-          declarationTokenPos: null,
-          scopeEndTokenPos: null,
-          scopeStartTokenPos: null,
-        ),
-        isolateRef,
-      ),
+  );
+}
+
+Variable buildMapVariable({int length = 2}) {
+  final mapVariable = buildParentMapVariable(length: length);
+
+  for (int i = 0; i < length; i++) {
+    mapVariable.addChild(
       Variable.create(
         BoundVariable(
-          name: "['key2']",
+          name: "['key${i + 1}']",
           value: InstanceRef(
-            id: 'ref11',
+            id: incrementRef(),
             kind: InstanceKind.kDouble,
-            classRef:
-                ClassRef(name: 'Double', id: 'ref12', library: libraryRef),
-            valueAsString: '1.1',
+            classRef: ClassRef(
+                name: 'Double', id: incrementRef(), library: libraryRef),
+            valueAsString: '${i + 1}.0',
             valueAsStringIsTruncated: false,
             identityHashCode: null,
           ),
@@ -780,15 +919,25 @@ final testVariables = [
         ),
         isolateRef,
       ),
-    ]),
-  Variable.create(
+    );
+  }
+
+  return mapVariable;
+}
+
+Variable buildStringVariable(String value) {
+  return Variable.create(
     BoundVariable(
-      name: 'Root 3',
+      name: incrementRoot(),
       value: InstanceRef(
-        id: 'ref13',
+        id: incrementRef(),
         kind: InstanceKind.kString,
-        classRef: ClassRef(name: 'String', id: 'ref14', library: libraryRef),
-        valueAsString: 'test str',
+        classRef: ClassRef(
+          name: 'String',
+          id: incrementRef(),
+          library: libraryRef,
+        ),
+        valueAsString: value,
         valueAsStringIsTruncated: true,
         identityHashCode: null,
       ),
@@ -797,15 +946,22 @@ final testVariables = [
       scopeStartTokenPos: null,
     ),
     isolateRef,
-  ),
-  Variable.create(
+  );
+}
+
+Variable buildBooleanVariable(bool value) {
+  return Variable.create(
     BoundVariable(
-      name: 'Root 4',
+      name: incrementRoot(),
       value: InstanceRef(
-        id: 'ref15',
+        id: incrementRef(),
         kind: InstanceKind.kBool,
-        classRef: ClassRef(name: 'Boolean', id: 'ref16', library: libraryRef),
-        valueAsString: 'true',
+        classRef: ClassRef(
+          name: 'Boolean',
+          id: incrementRef(),
+          library: libraryRef,
+        ),
+        valueAsString: '$value',
         valueAsStringIsTruncated: false,
         identityHashCode: null,
       ),
@@ -814,5 +970,5 @@ final testVariables = [
       scopeStartTokenPos: null,
     ),
     isolateRef,
-  ),
-];
+  );
+}
diff --git a/packages/devtools_test/lib/mocks.dart b/packages/devtools_test/lib/mocks.dart
index 5b8a9ed732a..9a736af6672 100644
--- a/packages/devtools_test/lib/mocks.dart
+++ b/packages/devtools_test/lib/mocks.dart
@@ -366,6 +366,16 @@ class FakeVmService extends Fake implements VmServiceWrapper {
     return Future.value(MockIsolate());
   }
 
+  @override
+  Future<Obj> getObject(
+    String isolateId,
+    String objectId, {
+    int offset,
+    int count,
+  }) {
+    return Future.value(MockObj());
+  }
+
   @override
   Future<MemoryUsage> getMemoryUsage(String isolateId) async {
     if (_memoryData == null) {
@@ -644,6 +654,8 @@ class MockVmService extends Mock implements VmServiceWrapper {}
 
 class MockIsolate extends Mock implements Isolate {}
 
+class MockObj extends Mock implements Obj {}
+
 class MockConnectedApp extends Mock implements ConnectedApp {}
 
 class FakeConnectedApp extends Mock implements ConnectedApp {}

From 6bd3ce5aa33e4a1938d9c5f24a3705f8d0136690 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 12 Nov 2021 10:59:30 -0800
Subject: [PATCH 08/19] Updated typed_data_variable_test

---
 .../lib/src/debugger/debugger_model.dart      |   7 +-
 .../lib/src/debugger/variables.dart           |   3 +-
 .../test/typed_data_variable_test.dart        | 142 ++++++++++++++++--
 3 files changed, 135 insertions(+), 17 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index ce3b38b8129..b7190f07ecb 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -463,8 +463,8 @@ Future<void> buildVariablesTree(
         // TODO(jacobr): cache the full class hierarchy so we can cheaply check
         // instanceRef is DiagnosticsNode without having to do an eval.
         if (instanceRef != null &&
-            (instanceRef.classRef.name == 'DiagnosticableTreeNode' ||
-                instanceRef.classRef.name == 'DiagnosticsProperty')) {
+            (instanceRef.classRef?.name == 'DiagnosticableTreeNode' ||
+                instanceRef.classRef?.name == 'DiagnosticsProperty')) {
           // The user is expecting to see the object the DiagnosticsNode is
           // describing not the DiagnosticsNode itself.
           try {
@@ -789,6 +789,9 @@ class Variable extends TreeNode<Variable> {
       } else if (value.kind == InstanceKind.kMap) {
         return value.length ?? 0;
       } else if (value.kind != null && value.kind.endsWith('List')) {
+        // Catch-all for Uint8ClampedList, Uint8List, Uint16List, Uint32List,
+        // Uint64List, Int8List, Int16List, Int32List, Int64List, Flooat32List,
+        // Float64List, Inst32x3List, Float32x4List, and Float64x2List types:
         return value.length ?? 0;
       }
     }
diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index fd8230e331d..fd976c1d4f7 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -221,7 +221,8 @@ class VariableSelectionControls extends MaterialTextSelectionControls {
       endpoints: endpoints,
       delegate: delegate,
       clipboardStatus: clipboardStatus,
-      handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
+      handleCut:
+          canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
       handleCopy: canCopy(delegate)
           ? () => handleCopy(delegate, clipboardStatus)
           : null,
diff --git a/packages/devtools_app/test/typed_data_variable_test.dart b/packages/devtools_app/test/typed_data_variable_test.dart
index 0e635d44da2..8165a4d498b 100644
--- a/packages/devtools_app/test/typed_data_variable_test.dart
+++ b/packages/devtools_app/test/typed_data_variable_test.dart
@@ -53,6 +53,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -64,7 +65,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -86,6 +88,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -97,7 +100,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -119,6 +123,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -130,7 +135,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -152,6 +158,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -163,7 +170,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -185,6 +193,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -196,7 +205,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -218,6 +228,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -229,7 +240,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -251,6 +263,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -262,7 +275,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -284,6 +298,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -295,7 +310,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -317,6 +333,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -328,7 +345,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -351,6 +369,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
     final variable = Variable.create(
       BoundVariable(
@@ -362,7 +381,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -383,6 +403,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
 
     final variable = Variable.create(
@@ -395,7 +416,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -417,6 +439,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
 
     final variable = Variable.create(
@@ -429,7 +452,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
     await buildVariablesTree(variable);
@@ -451,6 +475,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
 
     final variable = Variable.create(
@@ -463,7 +488,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -485,6 +511,7 @@ void main() {
       classRef: null,
       bytes: base64.encode(bytes.buffer.asUint8List()),
       identityHashCode: null,
+      length: 4,
     );
 
     final variable = Variable.create(
@@ -497,7 +524,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -508,6 +536,81 @@ void main() {
     expect(variable.children.first.displayValue, '[0, -1232.222]',
         skip: !kIsWeb);
   });
+
+  test('Retries getObject calls with no offset/count if error is thrown',
+      () async {
+    final bytes = Uint8List.fromList([0, 1, 2, 3]);
+    final instance = Instance(
+      kind: InstanceKind.kUint8List,
+      id: '123',
+      classRef: null,
+      bytes: base64.encode(bytes.buffer.asUint8List()),
+      identityHashCode: null,
+      length: 4,
+    );
+    final variable = Variable.create(
+      BoundVariable(
+        name: 'test',
+        value: instance,
+        declarationTokenPos: null,
+        scopeEndTokenPos: null,
+        scopeStartTokenPos: null,
+      ),
+      isolateRef,
+    );
+
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenThrow('Unrecognized parameters offset / count.');
+
+    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+      return instance;
+    });
+
+    await buildVariablesTree(variable);
+
+    expect(variable.children, [
+      matchesVariable(name: '[0]', value: 0),
+      matchesVariable(name: '[1]', value: 1),
+      matchesVariable(name: '[2]', value: 2),
+      matchesVariable(name: '[3]', value: 3),
+    ]);
+  });
+
+  test(
+      'Creates bound variable with groupings for children for a large Uint8ClampedList instance',
+      () async {
+    final instance = Instance(
+      kind: InstanceKind.kUint8ClampedList,
+      id: '123',
+      classRef: null,
+      bytes: null,
+      identityHashCode: null,
+      length: 332,
+    );
+    final variable = Variable.create(
+      BoundVariable(
+        name: 'test',
+        value: instance,
+        declarationTokenPos: null,
+        scopeEndTokenPos: null,
+        scopeStartTokenPos: null,
+      ),
+      isolateRef,
+    );
+    when(manager.service.getObject(any, any, offset: 0, count: 4))
+        .thenAnswer((_) async {
+      return instance;
+    });
+
+    await buildVariablesTree(variable);
+
+    expect(variable.children, [
+      matchesVariableGroup(start: 0, end: 99),
+      matchesVariableGroup(start: 100, end: 199),
+      matchesVariableGroup(start: 200, end: 299),
+      matchesVariableGroup(start: 300, end: 331),
+    ]);
+  });
 }
 
 Matcher matchesVariable({
@@ -521,3 +624,14 @@ Matcher matchesVariable({
           .having((v) => v.name, 'name', equals(name))
           .having((v) => v.ref.value, 'value', equals(value)));
 }
+
+Matcher matchesVariableGroup({
+  @required int start,
+  @required int end,
+}) {
+  return const TypeMatcher<Variable>().having(
+      (v) => v,
+      'boundVar',
+      const TypeMatcher<Variable>()
+          .having((v) => v.text, 'text', equals('[$start - $end]')));
+}

From bca0cf50407c71ab2c89256f1a3d10a224a08adf Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 12 Nov 2021 11:47:01 -0800
Subject: [PATCH 09/19] Remove clipboardStatus

---
 packages/devtools_app/lib/src/debugger/variables.dart | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index fd976c1d4f7..fd8230e331d 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -221,8 +221,7 @@ class VariableSelectionControls extends MaterialTextSelectionControls {
       endpoints: endpoints,
       delegate: delegate,
       clipboardStatus: clipboardStatus,
-      handleCut:
-          canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
+      handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
       handleCopy: canCopy(delegate)
           ? () => handleCopy(delegate, clipboardStatus)
           : null,

From 3e14186ac869be169324cf9b9ebc6f830ccd0c27 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 12 Nov 2021 12:36:40 -0800
Subject: [PATCH 10/19] Update association_variable_test

---
 .../devtools_app/test/association_variable_test.dart | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/devtools_app/test/association_variable_test.dart b/packages/devtools_app/test/association_variable_test.dart
index e3bf76b7c24..567407fe5b1 100644
--- a/packages/devtools_app/test/association_variable_test.dart
+++ b/packages/devtools_app/test/association_variable_test.dart
@@ -47,6 +47,7 @@ void main() {
       kind: InstanceKind.kMap,
       id: '123',
       classRef: null,
+      length: 2,
       associations: [
         MapAssociation(
           key: InstanceRef(
@@ -83,7 +84,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 2))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -111,6 +113,7 @@ void main() {
       kind: InstanceKind.kMap,
       id: '123',
       classRef: null,
+      length: 2,
       associations: [
         MapAssociation(
           key: InstanceRef(
@@ -141,7 +144,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 2))
+        .thenAnswer((_) async {
       return instance;
     });
 
@@ -168,6 +172,7 @@ void main() {
       kind: InstanceKind.kMap,
       id: '123',
       classRef: null,
+      length: 2,
       associations: [
         MapAssociation(
           key: InstanceRef(
@@ -197,7 +202,8 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any)).thenAnswer((_) async {
+    when(manager.service.getObject(any, any, offset: 0, count: 2))
+        .thenAnswer((_) async {
       return instance;
     });
 

From 381604aefc2bf22a4c7d1c78092227fe9a345f60 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 12 Nov 2021 13:51:23 -0800
Subject: [PATCH 11/19] Fix nesting

---
 .../test/debugger_screen_test.dart            | 220 +++++++++---------
 1 file changed, 111 insertions(+), 109 deletions(-)

diff --git a/packages/devtools_app/test/debugger_screen_test.dart b/packages/devtools_app/test/debugger_screen_test.dart
index 9d93e7f9c18..620a3a94946 100644
--- a/packages/devtools_app/test/debugger_screen_test.dart
+++ b/packages/devtools_app/test/debugger_screen_test.dart
@@ -513,119 +513,121 @@ void main() {
         expect(mapElement1Finder, findsOneWidget);
         expect(mapElement2Finder, findsOneWidget);
       });
-    });
 
-    testWidgetsWithWindowSize('Children in large list variables are grouped',
-        const Size(1000.0, 4000.0), (WidgetTester tester) async {
-      final list = buildParentListVariable(length: 380250);
-      await buildVariablesTree(list);
-      when(debuggerController.variables).thenReturn(
-        ValueNotifier(
-          [
-            list,
-          ],
-        ),
-      );
-      await pumpDebuggerScreen(tester, debuggerController);
+      testWidgetsWithWindowSize('Children in large list variables are grouped',
+          const Size(1000.0, 4000.0), (WidgetTester tester) async {
+        final list = buildParentListVariable(length: 380250);
+        await buildVariablesTree(list);
+        when(debuggerController.variables).thenReturn(
+          ValueNotifier(
+            [
+              list,
+            ],
+          ),
+        );
+        await pumpDebuggerScreen(tester, debuggerController);
 
-      final listFinder =
-          find.selectableText('Root 1: _GrowableList (380,250 items)');
-      final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
-      final group10000To19999Finder =
-          find.selectableTextContaining('[10000 - 19999]');
-      final group370000To379999Finder =
-          find.selectableTextContaining('[370000 - 379999]');
-      final group380000To380249Finder =
-          find.selectableTextContaining('[380000 - 380249]');
-
-      final group370000To370099Finder =
-          find.selectableTextContaining('[370000 - 370099]');
-      final group370100To370199Finder =
-          find.selectableTextContaining('[370100 - 370199]');
-      final group370200To370299Finder =
-          find.selectableTextContaining('[370200 - 370299]');
-
-      // Initially list is not expanded.
-      expect(listFinder, findsOneWidget);
-      expect(group0To9999Finder, findsNothing);
-      expect(group10000To19999Finder, findsNothing);
-      expect(group370000To379999Finder, findsNothing);
-      expect(group380000To380249Finder, findsNothing);
-
-      // Expand list.
-      await tester.tap(listFinder);
-      await tester.pump();
-      expect(group0To9999Finder, findsOneWidget);
-      expect(group10000To19999Finder, findsOneWidget);
-      expect(group370000To379999Finder, findsOneWidget);
-      expect(group380000To380249Finder, findsOneWidget);
-
-      // Initially group [370000 - 379999] is not expanded.
-      expect(group370000To370099Finder, findsNothing);
-      expect(group370100To370199Finder, findsNothing);
-      expect(group370200To370299Finder, findsNothing);
-
-      // Expand group [370000 - 379999].
-      await tester.tap(group370000To379999Finder);
-      await tester.pump();
-      expect(group370000To370099Finder, findsOneWidget);
-      expect(group370100To370199Finder, findsOneWidget);
-      expect(group370200To370299Finder, findsOneWidget);
-    });
+        final listFinder =
+            find.selectableText('Root 1: _GrowableList (380,250 items)');
+        final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
+        final group10000To19999Finder =
+            find.selectableTextContaining('[10000 - 19999]');
+        final group370000To379999Finder =
+            find.selectableTextContaining('[370000 - 379999]');
+        final group380000To380249Finder =
+            find.selectableTextContaining('[380000 - 380249]');
+
+        final group370000To370099Finder =
+            find.selectableTextContaining('[370000 - 370099]');
+        final group370100To370199Finder =
+            find.selectableTextContaining('[370100 - 370199]');
+        final group370200To370299Finder =
+            find.selectableTextContaining('[370200 - 370299]');
+
+        // Initially list is not expanded.
+        expect(listFinder, findsOneWidget);
+        expect(group0To9999Finder, findsNothing);
+        expect(group10000To19999Finder, findsNothing);
+        expect(group370000To379999Finder, findsNothing);
+        expect(group380000To380249Finder, findsNothing);
 
-    testWidgetsWithWindowSize('Children in large map variables are grouped',
-        const Size(1000.0, 4000.0), (WidgetTester tester) async {
-      final map = buildParentMapVariable(length: 243621);
-      await buildVariablesTree(map);
-      when(debuggerController.variables).thenReturn(
-        ValueNotifier(
-          [
-            map,
-          ],
-        ),
-      );
-      await pumpDebuggerScreen(tester, debuggerController);
+        // Expand list.
+        await tester.tap(listFinder);
+        await tester.pump();
+        expect(group0To9999Finder, findsOneWidget);
+        expect(group10000To19999Finder, findsOneWidget);
+        expect(group370000To379999Finder, findsOneWidget);
+        expect(group380000To380249Finder, findsOneWidget);
+
+        // Initially group [370000 - 379999] is not expanded.
+        expect(group370000To370099Finder, findsNothing);
+        expect(group370100To370199Finder, findsNothing);
+        expect(group370200To370299Finder, findsNothing);
+
+        // Expand group [370000 - 379999].
+        await tester.tap(group370000To379999Finder);
+        await tester.pump();
+        expect(group370000To370099Finder, findsOneWidget);
+        expect(group370100To370199Finder, findsOneWidget);
+        expect(group370200To370299Finder, findsOneWidget);
+      });
 
-      final listFinder =
-          find.selectableText('Root 1: _InternalLinkedHashmap (243,621 items)');
-      final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
-      final group10000To19999Finder =
-          find.selectableTextContaining('[10000 - 19999]');
-      final group230000To239999Finder =
-          find.selectableTextContaining('[230000 - 239999]');
-      final group240000To243620Finder =
-          find.selectableTextContaining('[240000 - 243620]');
-
-      final group0To99Finder = find.selectableTextContaining('[0 - 99]');
-      final group100To199Finder = find.selectableTextContaining('[100 - 199]');
-      final group200To299Finder = find.selectableTextContaining('[200 - 299]');
-
-      // Initially map is not expanded.
-      expect(listFinder, findsOneWidget);
-      expect(group0To9999Finder, findsNothing);
-      expect(group10000To19999Finder, findsNothing);
-      expect(group230000To239999Finder, findsNothing);
-      expect(group240000To243620Finder, findsNothing);
-
-      // Expand map.
-      await tester.tap(listFinder);
-      await tester.pump();
-      expect(group0To9999Finder, findsOneWidget);
-      expect(group10000To19999Finder, findsOneWidget);
-      expect(group230000To239999Finder, findsOneWidget);
-      expect(group240000To243620Finder, findsOneWidget);
-
-      // Initially group [0 - 9999] is not expanded.
-      expect(group0To99Finder, findsNothing);
-      expect(group100To199Finder, findsNothing);
-      expect(group200To299Finder, findsNothing);
-
-      // Expand group [0 - 9999].
-      await tester.tap(group0To9999Finder);
-      await tester.pump();
-      expect(group0To99Finder, findsOneWidget);
-      expect(group100To199Finder, findsOneWidget);
-      expect(group200To299Finder, findsOneWidget);
+      testWidgetsWithWindowSize('Children in large map variables are grouped',
+          const Size(1000.0, 4000.0), (WidgetTester tester) async {
+        final map = buildParentMapVariable(length: 243621);
+        await buildVariablesTree(map);
+        when(debuggerController.variables).thenReturn(
+          ValueNotifier(
+            [
+              map,
+            ],
+          ),
+        );
+        await pumpDebuggerScreen(tester, debuggerController);
+
+        final listFinder = find
+            .selectableText('Root 1: _InternalLinkedHashmap (243,621 items)');
+        final group0To9999Finder = find.selectableTextContaining('[0 - 9999]');
+        final group10000To19999Finder =
+            find.selectableTextContaining('[10000 - 19999]');
+        final group230000To239999Finder =
+            find.selectableTextContaining('[230000 - 239999]');
+        final group240000To243620Finder =
+            find.selectableTextContaining('[240000 - 243620]');
+
+        final group0To99Finder = find.selectableTextContaining('[0 - 99]');
+        final group100To199Finder =
+            find.selectableTextContaining('[100 - 199]');
+        final group200To299Finder =
+            find.selectableTextContaining('[200 - 299]');
+
+        // Initially map is not expanded.
+        expect(listFinder, findsOneWidget);
+        expect(group0To9999Finder, findsNothing);
+        expect(group10000To19999Finder, findsNothing);
+        expect(group230000To239999Finder, findsNothing);
+        expect(group240000To243620Finder, findsNothing);
+
+        // Expand map.
+        await tester.tap(listFinder);
+        await tester.pump();
+        expect(group0To9999Finder, findsOneWidget);
+        expect(group10000To19999Finder, findsOneWidget);
+        expect(group230000To239999Finder, findsOneWidget);
+        expect(group240000To243620Finder, findsOneWidget);
+
+        // Initially group [0 - 9999] is not expanded.
+        expect(group0To99Finder, findsNothing);
+        expect(group100To199Finder, findsNothing);
+        expect(group200To299Finder, findsNothing);
+
+        // Expand group [0 - 9999].
+        await tester.tap(group0To9999Finder);
+        await tester.pump();
+        expect(group0To99Finder, findsOneWidget);
+        expect(group100To199Finder, findsOneWidget);
+        expect(group200To299Finder, findsOneWidget);
+      });
     });
 
     WidgetPredicate createDebuggerButtonPredicate(String title) {

From 05eda968458bdd73942fddb03acd9f2773bd2584 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Fri, 12 Nov 2021 14:07:21 -0800
Subject: [PATCH 12/19] Remove redundant arg

---
 packages/devtools_app/test/typed_data_variable_test.dart | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/devtools_app/test/typed_data_variable_test.dart b/packages/devtools_app/test/typed_data_variable_test.dart
index 8165a4d498b..06f031e4259 100644
--- a/packages/devtools_app/test/typed_data_variable_test.dart
+++ b/packages/devtools_app/test/typed_data_variable_test.dart
@@ -583,7 +583,6 @@ void main() {
       kind: InstanceKind.kUint8ClampedList,
       id: '123',
       classRef: null,
-      bytes: null,
       identityHashCode: null,
       length: 332,
     );

From eb4084a1f9fe08763abcfe6d07130ee35f581c91 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 15 Nov 2021 12:43:23 -0800
Subject: [PATCH 13/19] Update in response to comments

---
 .../lib/src/debugger/debugger_model.dart      | 14 ++++++-------
 packages/devtools_app/lib/src/utils.dart      |  7 ++++---
 .../lib/src/vm_service_wrapper.dart           |  8 +++++--
 .../test/typed_data_variable_test.dart        | 21 +++++++++++++++++--
 4 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index b7190f07ecb..fe5bcea279a 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:convert';
+import 'dart:math';
 import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
@@ -382,13 +383,12 @@ Future<void> buildVariablesTree(
   }
 
   if (variable.childCount > Variable.MAX_CHILDREN_IN_GROUPING) {
-    final numChildrenInGrouping = variable.childCount >=
-            Variable.MAX_CHILDREN_IN_GROUPING *
-                Variable.MAX_CHILDREN_IN_GROUPING
-        ? (roundToNearestPow10(variable.childCount) /
-                Variable.MAX_CHILDREN_IN_GROUPING)
-            .floor()
-        : Variable.MAX_CHILDREN_IN_GROUPING;
+    final numChildrenInGrouping =
+        variable.childCount >= pow(Variable.MAX_CHILDREN_IN_GROUPING, 2)
+            ? (roundToNearestPow10(variable.childCount) /
+                    Variable.MAX_CHILDREN_IN_GROUPING)
+                .floor()
+            : Variable.MAX_CHILDREN_IN_GROUPING;
 
     var index = 0;
     while (index + numChildrenInGrouping < variable.childCount) {
diff --git a/packages/devtools_app/lib/src/utils.dart b/packages/devtools_app/lib/src/utils.dart
index f4fc99f25d3..b5ee29a0f22 100644
--- a/packages/devtools_app/lib/src/utils.dart
+++ b/packages/devtools_app/lib/src/utils.dart
@@ -188,13 +188,14 @@ T nullSafeMax<T extends num>(T a, T b) {
   return max<T>(a, b);
 }
 
-double logBase(num x, num base) {
+double logBase({@required int x, @required int base}) {
   return log(x) / log(base);
 }
 
-int log2(num x) => (logBase(x, 2)).floor();
+int log2(num x) => (logBase(x: x, base: 2)).floor();
 
-int roundToNearestPow10(num x) => pow(10, logBase(x, 10).ceil()).floor();
+int roundToNearestPow10(num x) =>
+    pow(10, logBase(x: x, base: 10).ceil()).floor();
 
 String isolateName(IsolateRef ref) {
   // analysis_server.dart.snapshot$main
diff --git a/packages/devtools_app/lib/src/vm_service_wrapper.dart b/packages/devtools_app/lib/src/vm_service_wrapper.dart
index f4cab2b5bda..152f18591b7 100644
--- a/packages/devtools_app/lib/src/vm_service_wrapper.dart
+++ b/packages/devtools_app/lib/src/vm_service_wrapper.dart
@@ -403,8 +403,12 @@ class VmServiceWrapper implements VmService {
   }) {
     return trackFuture(
         'getObject',
-        _vmService.getObject(isolateId, objectId,
-            offset: offset, count: count));
+        _vmService.getObject(
+          isolateId,
+          objectId,
+          offset: offset,
+          count: count,
+        ));
   }
 
   @override
diff --git a/packages/devtools_app/test/typed_data_variable_test.dart b/packages/devtools_app/test/typed_data_variable_test.dart
index 06f031e4259..eb7abd2b953 100644
--- a/packages/devtools_app/test/typed_data_variable_test.dart
+++ b/packages/devtools_app/test/typed_data_variable_test.dart
@@ -559,8 +559,12 @@ void main() {
       isolateRef,
     );
 
-    when(manager.service.getObject(any, any, offset: 0, count: 4))
-        .thenThrow('Unrecognized parameters offset / count.');
+    when(manager.service.getObject(
+      any,
+      any,
+      offset: 0,
+      count: 4,
+    )).thenThrow('Unrecognized parameters offset / count.');
 
     when(manager.service.getObject(any, any)).thenAnswer((_) async {
       return instance;
@@ -574,6 +578,19 @@ void main() {
       matchesVariable(name: '[2]', value: 2),
       matchesVariable(name: '[3]', value: 3),
     ]);
+
+    verifyInOrder([
+      manager.service.getObject(
+        any,
+        any,
+        offset: 0,
+        count: 4,
+      ),
+      manager.service.getObject(
+        any,
+        any,
+      ),
+    ]);
   });
 
   test(

From 69577825c42af92be0856b1eb49e46443867fc15 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 15 Nov 2021 13:00:51 -0800
Subject: [PATCH 14/19] Floor double to make it an int

---
 packages/devtools_app/lib/src/debugger/variables.dart | 3 ++-
 packages/devtools_app/lib/src/utils.dart              | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index fd8230e331d..fd976c1d4f7 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -221,7 +221,8 @@ class VariableSelectionControls extends MaterialTextSelectionControls {
       endpoints: endpoints,
       delegate: delegate,
       clipboardStatus: clipboardStatus,
-      handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
+      handleCut:
+          canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
       handleCopy: canCopy(delegate)
           ? () => handleCopy(delegate, clipboardStatus)
           : null,
diff --git a/packages/devtools_app/lib/src/utils.dart b/packages/devtools_app/lib/src/utils.dart
index b5ee29a0f22..9030ec2bc1a 100644
--- a/packages/devtools_app/lib/src/utils.dart
+++ b/packages/devtools_app/lib/src/utils.dart
@@ -192,7 +192,7 @@ double logBase({@required int x, @required int base}) {
   return log(x) / log(base);
 }
 
-int log2(num x) => (logBase(x: x, base: 2)).floor();
+int log2(num x) => (logBase(x: x.floor(), base: 2)).floor();
 
 int roundToNearestPow10(num x) =>
     pow(10, logBase(x: x, base: 10).ceil()).floor();

From 22447d4eaa12af91e3d188d5552af7a6740dbf0a Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 15 Nov 2021 13:48:32 -0800
Subject: [PATCH 15/19] Remove clipboardStatus

---
 packages/devtools_app/lib/src/debugger/variables.dart | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/variables.dart b/packages/devtools_app/lib/src/debugger/variables.dart
index fd976c1d4f7..fd8230e331d 100644
--- a/packages/devtools_app/lib/src/debugger/variables.dart
+++ b/packages/devtools_app/lib/src/debugger/variables.dart
@@ -221,8 +221,7 @@ class VariableSelectionControls extends MaterialTextSelectionControls {
       endpoints: endpoints,
       delegate: delegate,
       clipboardStatus: clipboardStatus,
-      handleCut:
-          canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
+      handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
       handleCopy: canCopy(delegate)
           ? () => handleCopy(delegate, clipboardStatus)
           : null,

From 0db2a627a3405e002433f0aa618707a91cae2496 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 15 Nov 2021 14:05:41 -0800
Subject: [PATCH 16/19] Switch roundToNearestPow10 to take an int as well

---
 packages/devtools_app/lib/src/utils.dart   | 2 +-
 packages/devtools_app/test/utils_test.dart | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/devtools_app/lib/src/utils.dart b/packages/devtools_app/lib/src/utils.dart
index 9030ec2bc1a..1f604abb520 100644
--- a/packages/devtools_app/lib/src/utils.dart
+++ b/packages/devtools_app/lib/src/utils.dart
@@ -194,7 +194,7 @@ double logBase({@required int x, @required int base}) {
 
 int log2(num x) => (logBase(x: x.floor(), base: 2)).floor();
 
-int roundToNearestPow10(num x) =>
+int roundToNearestPow10(int x) =>
     pow(10, logBase(x: x, base: 10).ceil()).floor();
 
 String isolateName(IsolateRef ref) {
diff --git a/packages/devtools_app/test/utils_test.dart b/packages/devtools_app/test/utils_test.dart
index 6a22316ba94..df4ae3242df 100644
--- a/packages/devtools_app/test/utils_test.dart
+++ b/packages/devtools_app/test/utils_test.dart
@@ -109,7 +109,6 @@ void main() {
     });
 
     test('roundToNearestPow10', () {
-      expect(roundToNearestPow10(0.1), equals(1));
       expect(roundToNearestPow10(1), equals(1));
       expect(roundToNearestPow10(2), equals(10));
       expect(roundToNearestPow10(10), equals(10));

From a987245bb2a644c0387bb531e462404224637ae7 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 15 Nov 2021 19:27:27 -0800
Subject: [PATCH 17/19] Modified loop and added test case

---
 .../lib/src/debugger/debugger_model.dart      | 17 ++++------
 .../test/typed_data_variable_test.dart        | 33 ++++++++++++++++---
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index fe5bcea279a..4655bcc1e1e 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -390,20 +390,15 @@ Future<void> buildVariablesTree(
                 .floor()
             : Variable.MAX_CHILDREN_IN_GROUPING;
 
-    var index = 0;
-    while (index + numChildrenInGrouping < variable.childCount) {
+    var start = variable.offset ?? 0;
+    final end = start + variable.childCount;
+    while (start < end) {
+      final count = min(end - start, numChildrenInGrouping);
       variable.addChild(
-        Variable.grouping(variable.ref,
-            offset: index + (variable.offset ?? 0),
-            count: numChildrenInGrouping),
+        Variable.grouping(variable.ref, offset: start, count: count),
       );
-      index += numChildrenInGrouping;
+      start += count;
     }
-    variable.addChild(
-      Variable.grouping(variable.ref,
-          offset: index + (variable.offset ?? 0),
-          count: variable.childCount - index),
-    );
   } else if (instanceRef != null && serviceManager.service != null) {
     try {
       final dynamic result =
diff --git a/packages/devtools_app/test/typed_data_variable_test.dart b/packages/devtools_app/test/typed_data_variable_test.dart
index eb7abd2b953..bb8df5fabe4 100644
--- a/packages/devtools_app/test/typed_data_variable_test.dart
+++ b/packages/devtools_app/test/typed_data_variable_test.dart
@@ -613,10 +613,6 @@ void main() {
       ),
       isolateRef,
     );
-    when(manager.service.getObject(any, any, offset: 0, count: 4))
-        .thenAnswer((_) async {
-      return instance;
-    });
 
     await buildVariablesTree(variable);
 
@@ -627,6 +623,35 @@ void main() {
       matchesVariableGroup(start: 300, end: 331),
     ]);
   });
+
+  test('Creates groupings of exactly 100 if the length is a multiple of 100',
+      () async {
+    final instance = Instance(
+      kind: InstanceKind.kUint8ClampedList,
+      id: '123',
+      classRef: null,
+      identityHashCode: null,
+      length: 300,
+    );
+    final variable = Variable.create(
+      BoundVariable(
+        name: 'test',
+        value: instance,
+        declarationTokenPos: null,
+        scopeEndTokenPos: null,
+        scopeStartTokenPos: null,
+      ),
+      isolateRef,
+    );
+
+    await buildVariablesTree(variable);
+
+    expect(variable.children, [
+      matchesVariableGroup(start: 0, end: 99),
+      matchesVariableGroup(start: 100, end: 199),
+      matchesVariableGroup(start: 200, end: 299),
+    ]);
+  });
 }
 
 Matcher matchesVariable({

From e3e225fabd6c8c35edafa353175f8df0181157f2 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Wed, 17 Nov 2021 09:50:43 -0800
Subject: [PATCH 18/19] Respond to PR comments

---
 .../lib/src/debugger/debugger_model.dart      | 19 +++++++------------
 .../test/debugger_screen_test.dart            | 11 +++++++----
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index 4655bcc1e1e..fcfe290c77a 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -697,6 +697,8 @@ List<Variable> _createVariablesForFields(
 // InstanceRef objects have become sentinels.
 // TODO(jacobr): consider a new class name. This class is more just the data
 // model for a tree of Dart objects with properties rather than a "Variable".
+// TODO(elliette): Refactor to make name, ref, text named (and potentially
+// required?) parameters. Give ref a type.
 class Variable extends TreeNode<Variable> {
   Variable._(this.name, ref, this.text, {int offset, int childCount})
       : _ref = ref,
@@ -767,10 +769,9 @@ class Variable extends TreeNode<Variable> {
   GenericInstanceRef get ref => _ref;
   GenericInstanceRef _ref;
 
-  int get offset {
-    if (_offset != null) return _offset;
-    return 0;
-  }
+  /// The point to fetch the variable from (in the case of large variables that
+  /// we fetch only parts of at a time).
+  int get offset => _offset ?? 0;
 
   int _offset;
 
@@ -779,14 +780,8 @@ class Variable extends TreeNode<Variable> {
 
     final value = this.value;
     if (value is InstanceRef) {
-      if (value.kind == InstanceKind.kList) {
-        return value.length ?? 0;
-      } else if (value.kind == InstanceKind.kMap) {
-        return value.length ?? 0;
-      } else if (value.kind != null && value.kind.endsWith('List')) {
-        // Catch-all for Uint8ClampedList, Uint8List, Uint16List, Uint32List,
-        // Uint64List, Int8List, Int16List, Int32List, Int64List, Flooat32List,
-        // Float64List, Inst32x3List, Float32x4List, and Float64x2List types:
+      if (value.kind != null &&
+          (value.kind.endsWith('List') || value.kind == InstanceKind.kMap)) {
         return value.length ?? 0;
       }
     }
diff --git a/packages/devtools_app/test/debugger_screen_test.dart b/packages/devtools_app/test/debugger_screen_test.dart
index 620a3a94946..f9cdb98cbb0 100644
--- a/packages/devtools_app/test/debugger_screen_test.dart
+++ b/packages/devtools_app/test/debugger_screen_test.dart
@@ -496,18 +496,21 @@ void main() {
           findsOneWidget,
         );
 
-        // Expand list.
+        // Initially list is not expanded.
         expect(find.selectableTextContaining('0: 3'), findsNothing);
         expect(find.selectableTextContaining('1: 4'), findsNothing);
 
+        // Expand list.
         await tester.tap(listFinder);
         await tester.pump();
         expect(find.selectableTextContaining('0: 0'), findsOneWidget);
         expect(find.selectableTextContaining('1: 1'), findsOneWidget);
 
-        // Expand map.
+        // Initially map is not expanded.
         expect(mapElement1Finder, findsNothing);
         expect(mapElement2Finder, findsNothing);
+
+        // Expand map.
         await tester.tap(mapFinder);
         await tester.pump();
         expect(mapElement1Finder, findsOneWidget);
@@ -813,7 +816,7 @@ final isolateRef = IsolateRef(
 int refNumber = 0;
 
 String incrementRef() {
-  refNumber = refNumber + 1;
+  refNumber++;
   return 'ref$refNumber';
 }
 
@@ -824,7 +827,7 @@ void resetRef() {
 int rootNumber = 0;
 
 String incrementRoot() {
-  rootNumber = rootNumber + 1;
+  rootNumber++;
   return 'Root $rootNumber';
 }
 

From 4894e831c08fc0479238b842ea9405cb0a3514fe Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Thu, 18 Nov 2021 10:38:56 -0800
Subject: [PATCH 19/19] check if list

---
 packages/devtools_app/lib/src/debugger/debugger_model.dart | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/devtools_app/lib/src/debugger/debugger_model.dart b/packages/devtools_app/lib/src/debugger/debugger_model.dart
index fcfe290c77a..1baaa60fa81 100644
--- a/packages/devtools_app/lib/src/debugger/debugger_model.dart
+++ b/packages/devtools_app/lib/src/debugger/debugger_model.dart
@@ -781,7 +781,9 @@ class Variable extends TreeNode<Variable> {
     final value = this.value;
     if (value is InstanceRef) {
       if (value.kind != null &&
-          (value.kind.endsWith('List') || value.kind == InstanceKind.kMap)) {
+          (value.kind.endsWith('List') ||
+              value.kind == InstanceKind.kList ||
+              value.kind == InstanceKind.kMap)) {
         return value.length ?? 0;
       }
     }