From 354be86b91a1a8e1ab60513d323162435b92a286 Mon Sep 17 00:00:00 2001
From: Chenjie Shi <tadelesh.shi@live.cn>
Date: Wed, 18 Sep 2024 22:40:51 +0800
Subject: [PATCH] [tcgc] handle orphan types in nested namespaces (#1558)

---
 ...n-model-in-nested-ns-2024-8-18-15-54-46.md |  7 +++++
 .../src/types.ts                              | 27 +++++++++++--------
 .../test/decorators/usage.test.ts             | 24 +++++++++++++++++
 3 files changed, 47 insertions(+), 11 deletions(-)
 create mode 100644 .chronus/changes/handle-orphan-model-in-nested-ns-2024-8-18-15-54-46.md

diff --git a/.chronus/changes/handle-orphan-model-in-nested-ns-2024-8-18-15-54-46.md b/.chronus/changes/handle-orphan-model-in-nested-ns-2024-8-18-15-54-46.md
new file mode 100644
index 0000000000..343879fd8e
--- /dev/null
+++ b/.chronus/changes/handle-orphan-model-in-nested-ns-2024-8-18-15-54-46.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+handle orphan types in nested namespaces
\ No newline at end of file
diff --git a/packages/typespec-client-generator-core/src/types.ts b/packages/typespec-client-generator-core/src/types.ts
index 8f583aec32..e872fb494b 100644
--- a/packages/typespec-client-generator-core/src/types.ts
+++ b/packages/typespec-client-generator-core/src/types.ts
@@ -1843,17 +1843,22 @@ export function getAllModelsWithDiagnostics(
   }
   // update for orphan models/enums/unions
   for (const client of listClients(context)) {
-    // orphan models
-    for (const model of client.service.models.values()) {
-      diagnostics.pipe(handleServiceOrphanType(context, model));
-    }
-    // orphan enums
-    for (const enumType of client.service.enums.values()) {
-      diagnostics.pipe(handleServiceOrphanType(context, enumType));
-    }
-    // orphan unions
-    for (const unionType of client.service.unions.values()) {
-      diagnostics.pipe(handleServiceOrphanType(context, unionType));
+    const namespaces = [client.service];
+    while (namespaces.length) {
+      const namespace = namespaces.pop()!;
+      // orphan models
+      for (const model of namespace.models.values()) {
+        diagnostics.pipe(handleServiceOrphanType(context, model));
+      }
+      // orphan enums
+      for (const enumType of namespace.enums.values()) {
+        diagnostics.pipe(handleServiceOrphanType(context, enumType));
+      }
+      // orphan unions
+      for (const unionType of namespace.unions.values()) {
+        diagnostics.pipe(handleServiceOrphanType(context, unionType));
+      }
+      namespaces.push(...namespace.namespaces.values());
     }
   }
   // update access
diff --git a/packages/typespec-client-generator-core/test/decorators/usage.test.ts b/packages/typespec-client-generator-core/test/decorators/usage.test.ts
index 745af36c0a..8ad5fec468 100644
--- a/packages/typespec-client-generator-core/test/decorators/usage.test.ts
+++ b/packages/typespec-client-generator-core/test/decorators/usage.test.ts
@@ -435,4 +435,28 @@ describe("typespec-client-generator-core: @usage", () => {
       code: "@azure-tools/typespec-client-generator-core/conflict-usage-override",
     });
   });
+
+  it("orphan model in group", async () => {
+    await runner.compileWithBuiltInService(
+      `
+        @access(Access.public)
+        @usage(Usage.output)
+        namespace Models {
+          model Model1 {
+            ref: Model2;
+          }
+
+          model Model2 {
+            name: string;
+          }
+        }
+      `
+    );
+    const models = runner.context.sdkPackage.models;
+    strictEqual(models.length, 2);
+    strictEqual(models[0].usage, UsageFlags.Output);
+    strictEqual(models[0].access, "public");
+    strictEqual(models[1].usage, UsageFlags.Output);
+    strictEqual(models[1].access, "public");
+  });
 });