Timothee Guerin (timotheeguerin) · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026
@@ -976,11 +976,11 @@ This scenario tests the exact() function applied to a model property with langua
 The property 'name' on ScopedModel is renamed using exact() scoped to each language,
 with names that include an underscore prefix to verify that language naming logic does not apply:
 
-- Python: '\_my_name' (should not be converted to 'my_name' or other casing)
-- Java: '\_myName' (should not be converted to remove the underscore prefix)
-- C#: '\_MyName' (should not be converted to remove the underscore prefix)
-- JavaScript: '\_myName' (should not be converted to remove the underscore prefix)
-- Go: '\_MyName' (should not be converted to remove the underscore prefix)
+- Python: '_my_name' (should not be converted to 'my_name' or other casing)
+- Java: '_myName' (should not be converted to remove the underscore prefix)
+- C#: '_MyName' (should not be converted to remove the underscore prefix)
+- JavaScript: '_myName' (should not be converted to remove the underscore prefix)
+- Go: '_MyName' (should not be converted to remove the underscore prefix)
   Each language should preserve the specified exact name as-is without any further casing conversion.
 
 Expected request body:

@@ -8,10 +8,7 @@ export type JsonSchema = {
 export type ResolvedJsonSchemaType = Exclude<JsonSchemaType, JsonSchemaRef>;
 
 export type JsonSchemaType =
-  | JsonSchemaObject
-  | JsonSchemaArray
-  | JsonSchemaPrimitive
-  | JsonSchemaRef;
+  JsonSchemaObject | JsonSchemaArray | JsonSchemaPrimitive | JsonSchemaRef;
 
 export interface JsonSchemaBase {
   $id?: string;

@@ -24,8 +24,7 @@ import type {
  * a particular service definition.
  */
 export type AutorestServiceRecord =
-  | AutorestUnversionedServiceRecord
-  | AutorestVersionedServiceRecord;
+  AutorestUnversionedServiceRecord | AutorestVersionedServiceRecord;
 
 export interface AutorestUnversionedServiceRecord extends AutorestEmitterResult {
   /** The service that generated this OpenAPI document */

@@ -8,12 +8,7 @@ export interface ArmResourceIdentifierConfig {
 }
 
 export type ArmResourceDeploymentScope =
-  | "Tenant"
-  | "Subscription"
-  | "ResourceGroup"
-  | "ManagementGroup"
-  | "ServiceGroup"
-  | "Extension";
+  "Tenant" | "Subscription" | "ResourceGroup" | "ManagementGroup" | "ServiceGroup" | "Extension";
 
 export interface ArmResourceIdentifierAllowedResource {
   /** The type of resource that is being referred to. For example Microsoft.Network/virtualNetworks or Microsoft.Network/virtualNetworks/subnets. See Example Types for more examples. */

@@ -185,10 +185,7 @@ export interface NextOperationReference extends LogicalOperationStep {
  * getting to a success result
  */
 export type FinalOperationStep =
-  | FinalOperationLink
-  | FinalOperationReference
-  | PollingSuccessProperty
-  | NoPollingSuccessProperty;
+  FinalOperationLink | FinalOperationReference | PollingSuccessProperty | NoPollingSuccessProperty;
 
 /**
  * For long-running operations, the resource link to the final result
@@ -296,9 +293,8 @@ export function getLroMetadata(program: Program, operation: Operation): LroMetad
   processFinalReference(program, operation, context);
   processFinalLink(program, operation, context);
   const nextReference:
-    | NextOperationReference
-    | (NextOperationLink & { operation: Operation })
-    | undefined = processStatusMonitorReference(program, operation, context);
+    NextOperationReference | (NextOperationLink & { operation: Operation }) | undefined =
+    processStatusMonitorReference(program, operation, context);
   if (nextReference !== undefined && nextReference.responseModel.kind === "Model") {
     context.statusMonitorStep = nextReference;
     const linkedOperation =

@@ -239,13 +239,7 @@ export type LegacyResourceOperationDecorator = (
   target: Operation,
   resourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => DecoratorValidatorCallbacks | void;
 
@@ -264,13 +258,7 @@ export type ExtensionResourceOperationDecorator = (
   targetResourceType: Model,
   extensionResourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => DecoratorValidatorCallbacks | void;
 
@@ -289,13 +277,7 @@ export type BuiltInResourceOperationDecorator = (
   parentResourceType: Model,
   builtInResourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => DecoratorValidatorCallbacks | void;
 
@@ -312,13 +294,7 @@ export type LegacyExtensionResourceOperationDecorator = (
   target: Operation,
   resourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => DecoratorValidatorCallbacks | void;
 

@@ -55,11 +55,7 @@ import {
 import { ArmStateKeys } from "./state.js";
 
 export type ArmLifecycleOperationKind =
-  | "read"
-  | "createOrUpdate"
-  | "update"
-  | "delete"
-  | "checkExistence";
+  "read" | "createOrUpdate" | "update" | "delete" | "checkExistence";
 export type ArmOperationKind = ArmLifecycleOperationKind | "list" | "action" | "other";
 
 export interface ArmResourceOperation extends ArmResourceOperationData {

@@ -768,13 +768,7 @@ function callOperationDecorator(
   resourceType: Model,
   resourceName: string,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
 ): void {
   switch (operationType) {
     case "read":
@@ -806,13 +800,7 @@ function callLifecycleDecorator(
   target: Operation,
   resourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
 ): void {
   switch (operationType) {
     case "read":
@@ -842,13 +830,7 @@ const $extensionResourceOperation: ExtensionResourceOperationDecorator = (
   targetResourceType: Model,
   extensionResourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => {
   if (
@@ -879,13 +861,7 @@ const $builtInResourceOperation: BuiltInResourceOperationDecorator = (
   parentResourceType: Model,
   builtInResourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => {
   if (
@@ -907,13 +883,7 @@ const $legacyResourceOperation: LegacyResourceOperationDecorator = (
   target: Operation,
   resourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => {
   if (
@@ -979,13 +949,7 @@ const $legacyExtensionResourceOperation: LegacyExtensionResourceOperationDecorat
   target: Operation,
   resourceType: Model,
   operationType:
-    | "read"
-    | "createOrUpdate"
-    | "update"
-    | "delete"
-    | "list"
-    | "action"
-    | "checkExistence",
+    "read" | "createOrUpdate" | "update" | "delete" | "list" | "action" | "checkExistence",
   resourceName?: string,
 ) => {
   if (

@@ -74,13 +74,7 @@ import { getArmResource, listArmResources, registerArmResource } from "./private
 import { ArmStateKeys } from "./state.js";
 
 export type ArmResourceKind =
-  | "Tracked"
-  | "Proxy"
-  | "Extension"
-  | "Virtual"
-  | "Custom"
-  | "BuiltIn"
-  | "Generic";
+  "Tracked" | "Proxy" | "Extension" | "Virtual" | "Custom" | "BuiltIn" | "Generic";
 
 /**
  * The base details for all kinds of resources

@@ -1884,17 +1884,15 @@ export function getClientOptionValue(
 ): unknown | undefined {
   // Check operation directly
   const opOption = getScopedDecoratorData(context, clientOptionKey, target) as
-    | { name: string; value: unknown }
-    | undefined;
+    { name: string; value: unknown } | undefined;
   if (opOption?.name === optionName) {
     return opOption.value;
   }
 
   // Check interface if operation is in one
   if (target.interface) {
     const ifaceOption = getScopedDecoratorData(context, clientOptionKey, target.interface) as
-      | { name: string; value: unknown }
-      | undefined;
+      { name: string; value: unknown } | undefined;
     if (ifaceOption?.name === optionName) {
       return ifaceOption.value;
     }
@@ -1904,8 +1902,7 @@ export function getClientOptionValue(
   let ns = target.namespace;
   while (ns) {
     const nsOption = getScopedDecoratorData(context, clientOptionKey, ns) as
-      | { name: string; value: unknown }
-      | undefined;
+      { name: string; value: unknown } | undefined;
     if (nsOption?.name === optionName) {
       return nsOption.value;
     }

@@ -647,10 +647,7 @@ export interface SdkModelPropertyTypeBase<
 }
 
 export type ArrayKnownEncoding =
-  | "pipeDelimited"
-  | "spaceDelimited"
-  | "commaDelimited"
-  | "newlineDelimited";
+  "pipeDelimited" | "spaceDelimited" | "commaDelimited" | "newlineDelimited";
 
 /**
  * Options to show how to serialize a model/property.
@@ -920,11 +917,7 @@ export interface SdkBodyParameter extends SdkModelPropertyTypeBase {
 }
 
 export type SdkHttpParameter =
-  | SdkQueryParameter
-  | SdkPathParameter
-  | SdkBodyParameter
-  | SdkHeaderParameter
-  | SdkCookieParameter;
+  SdkQueryParameter | SdkPathParameter | SdkBodyParameter | SdkHeaderParameter | SdkCookieParameter;
 
 export interface SdkMethodParameter extends SdkModelPropertyTypeBase {
   kind: "method";

@@ -544,15 +544,7 @@ export function getTypeDecorators(
 function getDecoratorArgValue(
   context: TCGCContext,
   arg:
-    | Type
-    | Record<string, unknown>
-    | Value
-    | unknown[]
-    | string
-    | number
-    | boolean
-    | Numeric
-    | null,
+    Type | Record<string, unknown> | Value | unknown[] | string | number | boolean | Numeric | null,
   type: Type,
   decoratorName: string,
 ): [any, readonly Diagnostic[]] {

@@ -212,8 +212,8 @@ function getSdkPagingServiceMethod<TServiceOperation extends SdkServiceOperation
       baseServiceMethod.response,
     );
 
-    baseServiceMethod.response.resultSegments = resultSegments?.map(
-      (resultSegment) => context.__modelPropertyCache.get(resultSegment)!,
+    baseServiceMethod.response.resultSegments = resultSegments?.map((resultSegment) =>
+      context.__modelPropertyCache.get(resultSegment)!,
     );
 
     context.__pagedResultSet.add(responseType);
@@ -254,14 +254,13 @@ function getSdkPagingServiceMethod<TServiceOperation extends SdkServiceOperation
                   context.program,
                   pagingMetadata.output.nextLink.property.type,
                 ) ?? []
-              ).map(
-                (t: ModelProperty) =>
-                  getPropertySegmentsFromModelOrParameters(
-                    baseServiceMethod.parameters,
-                    (p) =>
-                      p.__raw?.kind === "ModelProperty" &&
-                      findRootSourceProperty(p.__raw) === findRootSourceProperty(t),
-                  )!,
+              ).map((t: ModelProperty) =>
+                getPropertySegmentsFromModelOrParameters(
+                  baseServiceMethod.parameters,
+                  (p) =>
+                    p.__raw?.kind === "ModelProperty" &&
+                    findRootSourceProperty(p.__raw) === findRootSourceProperty(t),
+                )!,
               )
             : undefined,
       },

@@ -935,8 +935,7 @@ export function getSdkModelWithDiagnostics(
     const rawBaseModel = getLegacyHierarchyBuilding(context, type) || type.baseModel;
     if (rawBaseModel) {
       sdkType.baseModel = context.__referencedTypeCache.get(rawBaseModel) as
-        | SdkModelType
-        | undefined;
+        SdkModelType | undefined;
 
       if (sdkType.baseModel === undefined) {
         // Use "AdditionalProperty" label for Record base models

@@ -1203,16 +1203,14 @@ describe("Parameter", () => {
 
     // The foo method should NOT have subscriptionId as a method parameter (it's on client)
     const fooMethod = client.methods.find((m) => m.name === "foo") as
-      | SdkServiceMethod<SdkHttpOperation>
-      | undefined;
+      SdkServiceMethod<SdkHttpOperation> | undefined;
     ok(fooMethod);
     const fooSubIdMethodParam = fooMethod.parameters.find((p) => p.name === "subscriptionId");
     ok(!fooSubIdMethodParam);
 
     // The bar method SHOULD have subscriptionId as a method parameter (moved to method level)
     const barMethod = client.methods.find((m) => m.name === "bar") as
-      | SdkServiceMethod<SdkHttpOperation>
-      | undefined;
+      SdkServiceMethod<SdkHttpOperation> | undefined;
     ok(barMethod);
     const barSubIdMethodParam = barMethod.parameters.find((p) => p.name === "subscriptionId");
     ok(barSubIdMethodParam);
+7 −0		.chronus/changes/emitter-diff-tool-2026-7-2-0-0-0.md
+2 −2		.github/actions/setup/action.yml
+5 −4		.github/skills/csharp-spector-coverage-gaps/SKILL.md
+147 −0		.github/workflows/ci-emitter-diff-python.yml
+1 −0		AGENTS.md
+1 −0		cspell.yaml
+2 −1		eng/common/scripts/labels/policy.ts
+199 −0		eng/emitter-diff/README.md
+141 −0		eng/emitter-diff/src/baseline-cache.ts
+495 −0		eng/emitter-diff/src/cli.ts
+374 −0		eng/emitter-diff/src/diff.ts
+44 −0		eng/emitter-diff/src/registry.ts
+299 −0		eng/emitter-diff/src/resolver.ts
+74 −0		eng/emitter-diff/src/types.ts
+110 −0		eng/emitter-diff/src/util.ts
+9 −0		eng/emitter-diff/tsconfig.json
+1 −0		package.json
+1 −3		packages/asset-emitter/src/builders/object-builder.ts
+1 −7		packages/asset-emitter/src/types.ts
+4 −4		packages/compiler/src/core/checker.ts
+1 −2		packages/compiler/src/core/name-resolver.ts
+1 −3		packages/compiler/src/core/scanner.ts
+3 −16		packages/compiler/src/core/types.ts
+1 −3		packages/compiler/src/experimental/mutators.ts
+1 −3		packages/compiler/src/server/serverlib.ts
+2 −6		packages/compiler/src/server/tmlanguage.ts
+1 −2		packages/emitter-framework/src/python/components/class-declaration/class-method.tsx
+1 −2		packages/emitter-framework/src/python/components/class-declaration/pydantic-class-declaration.tsx
+1 −2		packages/emitter-framework/src/python/components/function-declaration/function-declaration.tsx
+1 −2		packages/emitter-framework/src/typescript/components/function-declaration.tsx
+1 −2		packages/emitter-framework/src/typescript/components/interface-declaration.tsx
+2 −8		packages/html-program-viewer/src/react/type-config.ts
+4 −9		packages/http-canonicalization/src/operation.ts
+1 −7		packages/http-canonicalization/src/options.ts
+1 −2		packages/http-client-csharp/emitter/src/lib/type-converter.ts
+1 −4		packages/http-client-csharp/emitter/src/type/input-type.ts
+1 −2		packages/http-client-csharp/emitter/test/Unit/client-initialization.test.ts
+1 −3		packages/http-client-js/test/e2e/http/payload/multipart/main.test.ts
+1 −2		packages/http-client-python/emitter/src/code-model.ts
+2 −1		packages/http-client-python/package.json
+1 −1		packages/http-server-js/generated-defs/package.json.ts
+1 −2		packages/http-server-js/src/util/differentiate.ts
+2 −2		packages/http-specs/spec-summary.md
+6 −10		packages/http/src/private.decorators.ts
+3 −9		packages/http/src/types.ts
+1 −5		packages/openapi3/src/cli/actions/convert/interfaces.ts
+3 −17		packages/openapi3/src/types.ts
+2 −7		packages/protobuf/src/ast.ts
+10 −21		packages/protobuf/src/transform/index.ts
+1 −7		packages/rest/src/rest.ts
+1 −3		packages/tmlanguage-generator/src/tmlanguage-generator.ts
+16 −18		packages/tspd/src/gen-extern-signatures/components/decorator-signature-type.tsx
+16 −18		packages/tspd/src/gen-extern-signatures/components/function-signature-type.tsx
+2 −2		packages/typespec-vscode/src/typespec-utils.ts
+2 −2		packages/versioning/test/versioning-timeline.test.ts
+39 −29		pnpm-lock.yaml
+1 −1		pnpm-workspace.yaml
+3 −0		tsconfig.eng.json
+15 −15		website/src/content/docs/docs/emitters/protobuf/reference/data-types.md
+3 −3		website/src/content/docs/docs/handbook/configuration/configuration.mdx
+1 −1		website/src/content/docs/docs/libraries/rest/reference/data-types.md