From 3b164761a791e371981ffa47c1df4ea477f1d4ba Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Tue, 12 Mar 2019 17:32:29 -0700
Subject: [PATCH 1/4] Don't clear set at end for flush reentrancy safety;
 canceling removes from set

---
 lib/utils/debounce.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/utils/debounce.js b/lib/utils/debounce.js
index 6fb246052b..bd6f6dd7d2 100644
--- a/lib/utils/debounce.js
+++ b/lib/utils/debounce.js
@@ -161,6 +161,5 @@ export const flushDebouncers = function() {
       });
     }
   });
-  debouncerQueue = new Set();
   return didFlush;
 };
\ No newline at end of file

From a23ac645619a9ced1dc26ae3ae0a7d742c82f07e Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Tue, 12 Mar 2019 18:28:44 -0700
Subject: [PATCH 2/4] Ensure debouncer is removed from queue before running
 callback.

---
 lib/utils/debounce.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/utils/debounce.js b/lib/utils/debounce.js
index bd6f6dd7d2..cf4311abbc 100644
--- a/lib/utils/debounce.js
+++ b/lib/utils/debounce.js
@@ -35,8 +35,8 @@ export class Debouncer {
     this._callback = callback;
     this._timer = this._asyncModule.run(() => {
       this._timer = null;
-      this._callback();
       debouncerQueue.delete(this);
+      this._callback();
     });
   }
   /**

From 5886be5da947179c72d9280ae1aa74acbef7a73d Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Tue, 12 Mar 2019 18:28:55 -0700
Subject: [PATCH 3/4] Add tests.

---
 test/unit/debounce.html | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/test/unit/debounce.html b/test/unit/debounce.html
index 5d20439147..2d770bb611 100644
--- a/test/unit/debounce.html
+++ b/test/unit/debounce.html
@@ -38,7 +38,7 @@
 
 suite('enqueueDebouncer & flush', function() {
 
-  // NOTE: This is a regression test; the bug it fixed only occured if the
+  // NOTE: This is a regression test; the bug it fixed only occurred if the
   // debouncer was flushed before any microtasks run, hence it should be
   // first in this file
   test('re-enqueue canceled debouncer', function() {
@@ -55,6 +55,16 @@
     assert.isTrue(cb.calledOnce);
   });
 
+  test('flushDebouncers from enqueued debouncer', function(done) {
+    const cb = sinon.spy(() => flush());
+    let db = Debouncer.debounce(null, microTask, cb);
+    enqueueDebouncer(db);
+    setTimeout(() => {
+      assert.isTrue(cb.calledOnce);
+      done();
+    })
+  });
+
   const testEnqueue = (shouldFlush, done) => {
     const actualOrder = [];
     const enqueue = (type, {db, cb} = {}) => {
@@ -89,6 +99,21 @@
     testEnqueue(true, done);
   });
 
+  test('reentrant flush', function() {
+    const cb2 = sinon.spy();
+    let db2;
+    const cb1 = sinon.spy(() => {
+      flush();
+      db2 = Debouncer.debounce(null, microTask, cb2);
+      enqueueDebouncer(db2);
+    });
+    const db1 = Debouncer.debounce(null, microTask, cb1);
+    enqueueDebouncer(db1);
+    flush();
+    assert.isTrue(cb1.calledOnce);
+    assert.isTrue(cb2.calledOnce);
+  });
+
 });
 
 suite('debounce', function() {

From 4cd703335fb0901c4d92da0d6200fd857fae3916 Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Tue, 12 Mar 2019 23:20:31 -0700
Subject: [PATCH 4/4] Fix lint

---
 test/unit/debounce.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit/debounce.html b/test/unit/debounce.html
index 2d770bb611..a5a97d599c 100644
--- a/test/unit/debounce.html
+++ b/test/unit/debounce.html
@@ -62,7 +62,7 @@
     setTimeout(() => {
       assert.isTrue(cb.calledOnce);
       done();
-    })
+    });
   });
 
   const testEnqueue = (shouldFlush, done) => {