[python] always respect namespace from TCGC (#5649)

fix #5661

---------

Co-authored-by: Chenjie Shi <tadelesh.shi@live.cn>

Author: msyyc

.chronus/changes/update-root-namespace-2025-2-12-6-11-5.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/http-client-python"
+---
+
+Always respect namespace from TCGC

packages/http-client-python/emitter/src/code-model.ts

@@ -1,5 +1,4 @@
 import {
-  SdkApiVersionParameter,
   SdkBasicServiceMethod,
   SdkClientType,
   SdkCredentialParameter,
@@ -33,12 +32,7 @@ import {
   simpleTypesMap,
   typesMap,
 } from "./types.js";
-import {
-  emitParamBase,
-  getClientNamespace,
-  getImplementation,
-  removeUnderscoresFromNamespace,
-} from "./utils.js";
+import { emitParamBase, getClientNamespace, getImplementation, getRootNamespace } from "./utils.js";
 
 function emitBasicMethod<TServiceOperation extends SdkServiceOperation>(
   context: PythonSdkContext<TServiceOperation>,
@@ -106,11 +100,7 @@ function emitLroPagingMethod<TServiceOperation extends SdkServiceOperation>(
 
 function emitMethodParameter<TServiceOperation extends SdkServiceOperation>(
   context: PythonSdkContext<TServiceOperation>,
-  parameter:
-    | SdkEndpointParameter
-    | SdkCredentialParameter
-    | SdkMethodParameter
-    | SdkApiVersionParameter,
+  parameter: SdkEndpointParameter | SdkCredentialParameter | SdkMethodParameter,
 ): Record<string, any>[] {
   if (parameter.kind === "endpoint") {
     if (parameter.type.kind === "union") {
@@ -286,7 +276,7 @@ export function emitCodeModel<TServiceOperation extends SdkServiceOperation>(
   // Get types
   const sdkPackage = sdkContext.sdkPackage;
   const codeModel: Record<string, any> = {
-    namespace: removeUnderscoresFromNamespace(sdkPackage.rootNamespace).toLowerCase(),
+    namespace: getRootNamespace(sdkContext),
     clients: [],
   };
   for (const client of sdkPackage.clients) {

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

@@ -16,7 +16,7 @@ import { saveCodeModelAsYaml } from "./external-process.js";
 import { PythonEmitterOptions, PythonSdkContext, reportDiagnostic } from "./lib.js";
 import { runPython3 } from "./run-python3.js";
 import { disableGenerationMap, simpleTypesMap, typesMap } from "./types.js";
-import { md2Rst, removeUnderscoresFromNamespace } from "./utils.js";
+import { getRootNamespace, md2Rst } from "./utils.js";
 
 export function getModelsMode(context: SdkContext): "dpg" | "none" {
   const specifiedModelsMode = context.emitContext.options["models-mode"];
@@ -50,9 +50,14 @@ function addDefaultOptions(sdkContext: SdkContext) {
     options["package-mode"] = sdkContext.arm ? "azure-mgmt" : "azure-dataplane";
   }
   if (!options["package-name"]) {
-    options["package-name"] = removeUnderscoresFromNamespace(
-      (sdkContext.sdkPackage.rootNamespace ?? "").toLowerCase(),
-    ).replace(/\./g, "-");
+    const namespace = getRootNamespace(sdkContext as PythonSdkContext<SdkServiceOperation>);
+    const packageName = namespace.replace(/\./g, "-");
+    reportDiagnostic(sdkContext.program, {
+      code: "no-package-name",
+      target: NoTarget,
+      format: { namespace, packageName },
+    });
+    options["package-name"] = packageName;
   }
   if (options.flavor !== "azure") {
     // if they pass in a flavor other than azure, we want to ignore the value
@@ -61,9 +66,6 @@ function addDefaultOptions(sdkContext: SdkContext) {
   if (!options.flavor && sdkContext.emitContext.emitterOutputDir.includes("azure")) {
     options.flavor = "azure";
   }
-  if (options["enable-typespec-namespace"] === undefined) {
-    options["enable-typespec-namespace"] = options.flavor !== "azure";
-  }
 }
 
 async function createPythonSdkContext<TServiceOperation extends SdkServiceOperation>(

packages/http-client-python/emitter/src/lib.ts

@@ -17,9 +17,7 @@ export interface PythonEmitterOptions {
   debug?: boolean;
   flavor?: "azure";
   "examples-dir"?: string;
-  // If true, package namespace will respect the typespec namespace. Otherwise,
-  // package namespace is always aligned with package name.
-  "enable-typespec-namespace"?: boolean;
+  namespace?: string;
   "use-pyodide"?: boolean;
 }
 
@@ -47,7 +45,7 @@ const EmitterOptionsSchema: JSONSchemaType<PythonEmitterOptions> = {
     debug: { type: "boolean", nullable: true },
     flavor: { type: "string", nullable: true },
     "examples-dir": { type: "string", nullable: true, format: "absolute-path" },
-    "enable-typespec-namespace": { type: "boolean", nullable: true },
+    namespace: { type: "string", nullable: true },
     "use-pyodide": { type: "boolean", nullable: true },
   },
   required: [],
@@ -77,6 +75,12 @@ const libDef = {
       },
     },
     // warning
+    "no-package-name": {
+      severity: "warning",
+      messages: {
+        default: paramMessage`No package-name configured in tspconfig.yaml and will infer package-name '${"packageName"}' from namespace '${"namespace"}'.`,
+      },
+    },
     "no-valid-client": {
       severity: "warning",
       messages: {

packages/http-client-python/emitter/src/utils.ts

@@ -242,31 +242,45 @@ export function capitalize(name: string): string {
   return name[0].toUpperCase() + name.slice(1);
 }
 
+const LIB_NAMESPACE = [
+  "azure.core",
+  "azure.resourcemanager",
+  "azure.clientgenerator.core",
+  "typespec.rest",
+  "typespec.http",
+  "typespec.versioning",
+];
+
+export function getRootNamespace(context: PythonSdkContext<SdkServiceOperation>): string {
+  let rootNamespace = "";
+  if (context.sdkPackage.clients.length > 0) {
+    rootNamespace = context.sdkPackage.clients[0].namespace;
+  } else if (context.sdkPackage.models.length > 0) {
+    const result = context.sdkPackage.models
+      .map((model) => model.namespace)
+      .filter((namespace) => !LIB_NAMESPACE.includes(namespace));
+    if (result.length > 0) {
+      result.sort();
+      rootNamespace = result[0];
+    }
+  } else if (context.sdkPackage.namespaces.length > 0) {
+    rootNamespace = context.sdkPackage.namespaces[0].fullName;
+  }
+
+  return removeUnderscoresFromNamespace(rootNamespace).toLowerCase();
+}
+
 export function getClientNamespace<TServiceOperation extends SdkServiceOperation>(
   context: PythonSdkContext<TServiceOperation>,
   clientNamespace: string,
 ) {
-  const rootNamespace = removeUnderscoresFromNamespace(
-    context.sdkPackage.rootNamespace,
-  ).toLowerCase();
-  if (!context.emitContext.options["enable-typespec-namespace"]) {
-    return rootNamespace;
-  }
   if (
-    [
-      "azure.core",
-      "azure.resourcemanager",
-      "azure.clientgenerator.core",
-      "typespec.rest",
-      "typespec.http",
-      "typespec.versioning",
-    ].some((item) => clientNamespace.toLowerCase().startsWith(item))
+    clientNamespace === "" ||
+    LIB_NAMESPACE.some((item) => clientNamespace.toLowerCase().startsWith(item))
   ) {
-    return rootNamespace;
+    return getRootNamespace(context);
   }
-  return clientNamespace === ""
-    ? rootNamespace
-    : removeUnderscoresFromNamespace(clientNamespace).toLowerCase();
+  return removeUnderscoresFromNamespace(clientNamespace).toLowerCase();
 }
 
 function parseToken(token: Token): string {