fix(client-fetch): narrow headers to Headers in ResolvedRequestOptions

The headers property in ResolvedRequestOptions was inherited as a broad
union from CoreConfig (RequestInit['headers'] | Record<string, ...>),
but at runtime mergeHeaders() always produces a Headers instance.

This narrows the type in ResolvedRequestOptions so request interceptors
can use .set(), .get(), .delete() etc. without casting.

Closes #3372

Author: inas-sirhan

.changeset/fix-resolved-request-options-headers.md

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-fastify/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-fetch/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-nestjs/src/client/client/types.gen.ts

@@ -93,6 +93,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-openai/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-pinia-colada/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-tanstack-react-query/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-tanstack-svelte-query/src/client/client/types.gen.ts

@@ -90,6 +90,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }
 

examples/openapi-ts-tanstack-vue-query/src/client/client/types.gen.ts

@@ -93,6 +93,7 @@ export interface ResolvedRequestOptions<
   ThrowOnError extends boolean = boolean,
   Url extends string = string,
 > extends RequestOptions<unknown, TResponseStyle, ThrowOnError, Url> {
+  headers: Headers;
   serializedBody?: string;
 }