fix(typespec-metadata): derive Go package name from emitter-output-dir instead of module path

.chronus/changes/fix-go-package-name-output-dir-2026-6-11.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-metadata"
+---
+
+Fix incorrect Go package name parsing in `tspconfig.yaml`. The Go package name is now derived from the emitter output directory instead of the module path, which correctly excludes version suffixes (e.g., `/v4`) and uses the language-specific `service-dir` for accurate path resolution.

packages/typespec-metadata/src/collector.ts

@@ -257,7 +257,10 @@ function parseTypeScript(
 
 /**
  * Go-specific metadata parser.
- * Extracts from module path, looking for azure-sdk-for-go suffix.
+ * Extracts from module path, looking for azure-sdk-for-go suffix, as a fallback.
+ * The primary derivation of package name from the emitter output directory is handled
+ * by the caller (createLanguageMetadata) after the relative output path is computed,
+ * because it requires knowledge of the base output directory.
  */
 function parseGo(
   options: Record<string, unknown>,
@@ -560,6 +563,21 @@ function createLanguageMetadata(
     relativeOutputDir = relativeOutputDir.replace(/\{namespace\}/g, namespace);
   }
 
+  // For Go, prefer the emitter output directory over the module path for package name derivation.
+  // The output directory gives the correct repo-relative path (e.g., sdk/resourcemanager/redisenterprise/armredisenterprise)
+  // without version suffixes that may appear in the module path (e.g., /v4).
+  if (heuristicLang === "go" && relativeOutputDir?.startsWith("{output-dir}/")) {
+    const explicitPackageName =
+      normalizedOptions["package-name"] ?? normalizedOptions["package_name"];
+    if (!explicitPackageName) {
+      const outputDirPackageName = relativeOutputDir.substring("{output-dir}/".length);
+      packageName = outputDirPackageName;
+      if (!normalizedOptions["namespace"]) {
+        namespace = outputDirPackageName;
+      }
+    }
+  }
+
   return {
     emitterName,
     packageName,

packages/typespec-metadata/test/collector.test.ts

@@ -294,6 +294,67 @@ describe("language-specific parsers", () => {
   });
 });
 
+describe("@azure-tools/typespec-go emitter", () => {
+  it("should derive package name from emitter-output-dir instead of module path", () => {
+    // Simulates the redisenterprise scenario where module includes version suffix (/v4)
+    // but the emitter-output-dir gives the correct package path without the suffix.
+    const optionMap: Record<string, Record<string, unknown>> = {
+      "@azure-tools/typespec-go": {
+        module:
+          "github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/redisenterprise/armredisenterprise/v4",
+        "service-dir": "sdk/resourcemanager/redisenterprise",
+        "emitter-output-dir":
+          "c:/repos/tsp-output/sdk/resourcemanager/redisenterprise/armredisenterprise",
+        "generate-fakes": true,
+        flavor: "azure",
+      },
+    };
+
+    const result = buildLanguageMetadata(optionMap, {}, "c:/repos/tsp-output");
+    const lang = result["go"][0];
+
+    // Should use output dir path (without /v4 version suffix), not module path
+    expect(lang.packageName).toBe("sdk/resourcemanager/redisenterprise/armredisenterprise");
+    expect(lang.namespace).toBe("sdk/resourcemanager/redisenterprise/armredisenterprise");
+    expect(lang.outputDir).toBe(
+      "{output-dir}/sdk/resourcemanager/redisenterprise/armredisenterprise",
+    );
+  });
+
+  it("should fall back to module path when emitter-output-dir is not under base output dir", () => {
+    const optionMap: Record<string, Record<string, unknown>> = {
+      "@azure-tools/typespec-go": {
+        module: "github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/azsecrets",
+      },
+    };
+
+    const result = buildLanguageMetadata(optionMap, {}, "/repos/tsp-output");
+    const lang = result["go"][0];
+
+    // No emitter-output-dir, falls back to module path
+    expect(lang.packageName).toBe("sdk/security/keyvault/azsecrets");
+    expect(lang.namespace).toBe("sdk/security/keyvault/azsecrets");
+  });
+
+  it("should respect explicit package-name over emitter-output-dir", () => {
+    const optionMap: Record<string, Record<string, unknown>> = {
+      "@azure-tools/typespec-go": {
+        "package-name": "sdk/custom/myPackage",
+        module: "github.com/Azure/azure-sdk-for-go/sdk/some/module/v2",
+        "emitter-output-dir":
+          "c:/repos/tsp-output/sdk/resourcemanager/redisenterprise/armredisenterprise",
+        flavor: "azure",
+      },
+    };
+
+    const result = buildLanguageMetadata(optionMap, {}, "c:/repos/tsp-output");
+    const lang = result["go"][0];
+
+    // Explicit package-name should not be overridden by emitter-output-dir
+    expect(lang.packageName).toBe("sdk/custom/myPackage");
+  });
+});
+
 describe("service-dir handling", () => {
   it("should use language-specific service-dir if present", () => {
     const languageServiceDir = "sdk/security/keyvault";