fix normalize issue for optional operation parameter name

packages/rlc-common/src/helpers/nameUtils.ts

@@ -157,7 +157,8 @@ export function normalizeName(
   nameType: NameType,
   shouldGuard?: boolean,
   customReservedNames?: ReservedName[],
-  casingOverride?: CasingConvention
+  casingOverride?: CasingConvention,
+  oriName?: string
 ): string;
 export function normalizeName(
   name: string,
@@ -169,7 +170,8 @@ export function normalizeName(
   nameType: NameType,
   optionsOrShouldGuard?: NormalizeNameOption | boolean,
   optionalCustomReservedNames?: ReservedName[],
-  optionalCasingOverride?: CasingConvention
+  optionalCasingOverride?: CasingConvention,
+  oriName?: string
 ): string {
   let shouldGuard: boolean | undefined,
     customReservedNames: ReservedName[],
@@ -185,8 +187,8 @@ export function normalizeName(
     casingOverride = optionsOrShouldGuard?.casingOverride;
     numberPrefixOverride = optionsOrShouldGuard?.numberPrefixOverride;
   }
-  if (name.startsWith("$DO_NOT_NORMALIZE$")) {
-    return name.replace("$DO_NOT_NORMALIZE$", "");
+  if ((oriName ?? name).startsWith("$DO_NOT_NORMALIZE$")) {
+    return (oriName ?? name).replace("$DO_NOT_NORMALIZE$", "");
   }
   const casingConvention = casingOverride ?? getCasingConvention(nameType);
   const parts = deconstruct(name);

packages/typespec-ts/src/utils/operationUtil.ts

@@ -670,6 +670,14 @@ export type ServiceOperation = SdkServiceMethod<SdkHttpOperation> & {
   oriName?: string;
 };
 
+export type ServiceParameter = (
+  | SdkMethodParameter
+  | SdkHttpParameter
+  | SdkBodyParameter
+) & {
+  oriName?: string;
+};
+
 export function getMethodHierarchiesMap(
   context: SdkContext,
   client: SdkClientType<SdkServiceOperation>
@@ -804,9 +812,21 @@ export function isTenantLevelOperation(
 
 function resolveParameterNameConflict(
   operationOrGroup: SdkServiceMethod<SdkHttpOperation>,
-  p: SdkMethodParameter | SdkHttpParameter | SdkBodyParameter
-): SdkMethodParameter | SdkHttpParameter | SdkBodyParameter {
-  const paramName = normalizeName(p.name, NameType.Parameter, true);
+  p: ServiceParameter
+): ServiceParameter {
+  // When the name starts with $DO_NOT_NORMALIZE$, record the original name so that
+  // subsequent calls (e.g. emitNonModelResponseTypes then buildApiOptions both call
+  // getMethodHierarchiesMap on the same TCGC object) always normalize from the
+  // original, not from the already-mutated value.
+  const paramName = normalizeName(
+    p.name,
+    NameType.Parameter,
+    true,
+    undefined,
+    undefined,
+    p.oriName
+  );
+  p.oriName = p.name;
   if (paramName === operationOrGroup.name) {
     p.name = `${paramName}Parameter`;
   } else {

packages/typespec-ts/test/modularUnit/scenarios/operations/doNotNormalizeReservedParam.md

@@ -0,0 +1,113 @@
+# Should keep optional query param name when $DO_NOT_NORMALIZE$ is applied to a reserved keyword
+
+## Typespec
+
+```tsp
+import "@typespec/http";
+import "@azure-tools/typespec-client-generator-core";
+
+using TypeSpec.Http;
+using Azure.ClientGenerator.Core;
+
+@service
+namespace Test;
+
+interface Test {
+  @route("/test")
+  op patch(@query("type") type?: string): void;
+}
+
+@@clientName(Test.patch::parameters.type, "$DO_NOT_NORMALIZE$type");
+```
+
+This is the tspconfig.yaml.
+
+```yaml
+withRawContent: true
+mustEmptyDiagnostic: false
+experimental-extensible-enums: true
+```
+
+## Operations Options
+
+```ts models:withOptions interface PatchOptionalParams
+export interface PatchOptionalParams extends OperationOptions {
+  type?: string;
+}
+```
+
+# Should keep optional header param name when $DO_NOT_NORMALIZE$ is applied to a reserved keyword
+
+## Typespec
+
+```tsp
+import "@typespec/http";
+import "@azure-tools/typespec-client-generator-core";
+
+using TypeSpec.Http;
+using Azure.ClientGenerator.Core;
+
+@service
+namespace Test;
+
+interface Test {
+  @route("/test")
+  op patch(@header("type") type?: string): void;
+}
+
+@@clientName(Test.patch::parameters.type, "$DO_NOT_NORMALIZE$type");
+```
+
+This is the tspconfig.yaml.
+
+```yaml
+withRawContent: true
+mustEmptyDiagnostic: false
+experimental-extensible-enums: true
+```
+
+## Operations Options
+
+```ts models:withOptions interface PatchOptionalParams
+export interface PatchOptionalParams extends OperationOptions {
+  type?: string;
+}
+```
+
+# Should keep optional body param name when $DO_NOT_NORMALIZE$ is applied to a reserved keyword
+
+## Typespec
+
+```tsp
+import "@typespec/http";
+import "@azure-tools/typespec-client-generator-core";
+
+using TypeSpec.Http;
+using Azure.ClientGenerator.Core;
+
+@service
+namespace Test;
+
+interface Test {
+  @route("/test")
+  op patch(@body type?: string): void;
+}
+
+@@clientName(Test.patch::parameters.type, "$DO_NOT_NORMALIZE$type");
+```
+
+This is the tspconfig.yaml.
+
+```yaml
+withRawContent: true
+mustEmptyDiagnostic: false
+experimental-extensible-enums: true
+```
+
+## Operations Options
+
+```ts models:withOptions interface PatchOptionalParams
+export interface PatchOptionalParams extends OperationOptions {
+  type?: string;
+}
+```