fix: prevent crash when package-name option is missing in http-client-csharp

packages/http-client-csharp/emitter/src/emitter.ts

@@ -116,15 +116,19 @@ export async function $onEmit(context: EmitContext<CSharpEmitterOptions>) {
           const isValid = await _validateDotNetSdk(sdkContext, _minSupportedDotNetSdkVersion);
           // if the dotnet sdk is valid, the error is not dependency issue, log it as normal
           if (isValid) {
-            throw new Error(
-              `Failed to generate the library. Exit code: ${result.exitCode}.\nStackTrace: \n${result.stderr}`,
+            sdkContext.logger.error(
+              `Failed to generate the library. Exit code: ${result.exitCode}.\n${result.stderr}`,
             );
           }
         }
       } catch (error: any) {
         const isValid = await _validateDotNetSdk(sdkContext, _minSupportedDotNetSdkVersion);
         // if the dotnet sdk is valid, the error is not dependency issue, log it as normal
-        if (isValid) throw new Error(error);
+        if (isValid) {
+          sdkContext.logger.error(
+            `Failed to generate the library. Error: ${error.message ?? error}`,
+          );
+        }
       }
       if (!options["save-inputs"]) {
         // delete

packages/http-client-csharp/emitter/test/Unit/emitter.test.ts

@@ -94,6 +94,26 @@ describe("$onEmit tests", () => {
     expect(updateCallback).toHaveBeenCalledTimes(1);
   });
 
+  it("should report diagnostic instead of throwing when generator fails", async () => {
+    vi.mocked(execCSharpGenerator).mockResolvedValueOnce({
+      exitCode: 1,
+      stdout: "",
+      stderr: "Unable to parse required option package-name from configuration.",
+    } as any);
+    vi.mocked(execAsync).mockResolvedValueOnce({
+      exitCode: 0,
+      stdio: "",
+      stdout: "9.0.102",
+      stderr: "",
+      proc: { pid: 0, output: "", stdout: "", stderr: "", stdin: "" },
+    } as any);
+
+    const context: EmitContext<CSharpEmitterOptions> = createEmitterContext(program);
+    // should not throw
+    await $onEmit(context);
+    expect(program.reportDiagnostics).toHaveBeenCalled();
+  });
+
   it("should apply sdk-context-options", async () => {
     const context: EmitContext<CSharpEmitterOptions> = createEmitterContext(program);
     const additionalDecorators = ["Decorator1", "Decorator2"];

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/CodeModelGenerator.cs

@@ -108,6 +108,12 @@ internal set
 
         protected internal virtual void Configure()
         {
+            if (Configuration.PackageName == Configuration.DefaultPackageName)
+            {
+                Configuration.PackageName = TypeFactory.PrimaryNamespace;
+                Emitter.Info($"'package-name' was not specified. Defaulting to namespace '{Configuration.PackageName}'.");
+            }
+
             foreach (var type in CustomCodeAttributeProviders)
             {
                 AddTypeToKeep(type);

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/Configuration.cs

@@ -22,6 +22,7 @@ public enum UnreferencedTypesHandlingOption
 
         private const string GeneratedFolderName = "Generated";
         private const string ConfigurationFileName = "Configuration.json";
+        internal const string DefaultPackageName = "GeneratedClient";
 
 #pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
         protected Configuration()
@@ -84,7 +85,7 @@ private static class Options
         private string? _testGeneratedDirectory;
         internal string TestGeneratedDirectory => _testGeneratedDirectory ??= Path.Combine(TestProjectDirectory, GeneratedFolderName);
 
-        public string PackageName { get; }
+        public string PackageName { get; internal set; }
 
         /// <summary>
         /// True if a sample project should be generated.
@@ -120,7 +121,7 @@ internal static Configuration Load(string outputPath, string? json = null)
             return new Configuration(
                 Path.GetFullPath(outputPath),
                 ParseAdditionalConfigOptions(root),
-                ReadRequiredStringOption(root, Options.PackageName),
+                ReadStringOption(root, Options.PackageName) ?? DefaultPackageName,
                 ReadOption(root, Options.DisableXmlDocs),
                 ReadEnumOption<UnreferencedTypesHandlingOption>(root, Options.UnreferencedTypesHandling),
                 ReadLicenseInfo(root));
@@ -178,11 +179,6 @@ private static bool ReadOption(JsonElement root, string option)
             }
         }
 
-        private static string ReadRequiredStringOption(JsonElement root, string option)
-        {
-            return ReadStringOption(root, option) ?? throw new InvalidOperationException($"Unable to parse required option {option} from configuration.");
-        }
-
         private static string? ReadStringOption(JsonElement root, string option)
         {
             if (root.TryGetProperty(option, out JsonElement value))

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/test/ConfigurationTests.cs

@@ -66,20 +66,48 @@ public void TestParseConfig_OutputFolder(string mockJson, bool throwsError)
 
         // Validates that the LibraryName field is parsed correctly from the configuration
         [TestCaseSource("ParseConfigLibraryNameTestCases")]
-        public void TestParseConfig_LibraryName(string mockJson, bool throwsError)
+        public void TestParseConfig_LibraryName(string mockJson, string expected)
         {
-            if (throwsError)
-            {
-                Assert.Throws<InvalidOperationException>(() => MockHelpers.LoadMockGenerator(configuration: mockJson));
-                return;
-            }
+            MockHelpers.LoadMockGenerator(configuration: mockJson);
 
             var library = CodeModelGenerator.Instance.Configuration.PackageName;
-            var expected = "libraryName";
 
             Assert.AreEqual(expected, library);
         }
 
+        // Validates that when package-name is not specified, Configure() defaults to the PrimaryNamespace
+        [Test]
+        public void TestParseConfig_PackageNameDefaultsToPrimaryNamespace()
+        {
+            var mockJson = @"{
+                ""output-folder"": ""outputFolder""
+            }";
+
+            MockHelpers.LoadMockGenerator(configuration: mockJson, inputNamespaceName: "My.Custom.Namespace");
+
+            // Before Configure, package name should be the default
+            Assert.AreEqual(Configuration.DefaultPackageName, CodeModelGenerator.Instance.Configuration.PackageName);
+
+            // After Configure, package name should be resolved from the namespace
+            CodeModelGenerator.Instance.Configure();
+            Assert.AreEqual("My.Custom.Namespace", CodeModelGenerator.Instance.Configuration.PackageName);
+        }
+
+        // Validates that when package-name is explicitly set, Configure() does not override it
+        [Test]
+        public void TestParseConfig_ExplicitPackageNameNotOverridden()
+        {
+            var mockJson = @"{
+                ""output-folder"": ""outputFolder"",
+                ""package-name"": ""ExplicitName""
+            }";
+
+            MockHelpers.LoadMockGenerator(configuration: mockJson, inputNamespaceName: "My.Custom.Namespace");
+
+            CodeModelGenerator.Instance.Configure();
+            Assert.AreEqual("ExplicitName", CodeModelGenerator.Instance.Configuration.PackageName);
+        }
+
         // Validates that additional configuration options are parsed correctly
         [Test]
         public void TestParseConfig_AdditionalConfigOptions()
@@ -273,11 +301,11 @@ public static IEnumerable<TestCaseData> ParseConfigLibraryNameTestCases
             {
                 yield return new TestCaseData(@"{
                     ""output-folder"": ""outputFolder"",
-                    ""package-name"": ""libraryName"",
-                }", false);
+                    ""package-name"": ""libraryName""
+                }", "libraryName");
                 yield return new TestCaseData(@"{
                     ""output-folder"": ""outputFolder""
-                }", true);
+                }", Configuration.DefaultPackageName);
             }
         }