fix(api): prevent cleanup leaking into request config

Author: easonliang28

src/api/providers/__tests__/request-config-builder.spec.ts

@@ -24,6 +24,13 @@ describe("RequestConfigBuilder", () => {
 			const result = builder.build()
 			expect(result?.modelId).toBe("test-model")
 		})
+
+		test("should initialize cleanup as a no-op", () => {
+			const builder = new RequestConfigBuilder()
+
+			expect(builder.getCleanup()).toBeTypeOf("function")
+			expect(() => builder.getCleanup()()).not.toThrow()
+		})
 	})
 
 	describe("addAbortSignal", () => {
@@ -316,7 +323,8 @@ describe("RequestConfigBuilder", () => {
 			expect(result).toBe(builder)
 			const config = builder.build() as { signal?: AbortSignal; _cleanup?: () => void }
 			expect(config.signal).toBe(internalController.signal)
-			expect(config._cleanup).toBeTypeOf("function")
+			expect(config).not.toHaveProperty("_cleanup")
+			expect(builder.getCleanup()).toBeTypeOf("function")
 		})
 
 		test("should merge internal controller signal with metadata abort signal", () => {
@@ -346,12 +354,13 @@ describe("RequestConfigBuilder", () => {
 
 			const config = builder.build() as { signal?: AbortSignal; _cleanup?: () => void }
 			expect(config.signal).not.toBe(internalController.signal)
+			expect(config).not.toHaveProperty("_cleanup")
 			expect(config.signal?.aborted).toBe(false)
 
 			await vi.advanceTimersByTimeAsync(100)
 
 			expect(config.signal?.aborted).toBe(true)
-			config._cleanup?.()
+			builder.getCleanup()()
 			vi.useRealTimers()
 		})
 	})

src/api/providers/config-builder/request-config-builder.ts

@@ -13,6 +13,7 @@ import { mergeAbortSignalAndTimeout, mergeAbortSignals } from "../utils/abort-si
  */
 export class RequestConfigBuilder<TOptions extends Record<string, any> = Record<string, any>> {
 	protected options: TOptions
+	private cleanupFn: () => void = () => {}
 
 	constructor(defaultOptions?: Partial<TOptions>) {
 		this.options = (defaultOptions ? { ...defaultOptions } : {}) as TOptions
@@ -68,10 +69,20 @@ export class RequestConfigBuilder<TOptions extends Record<string, any> = Record<
 		const merged = mergeAbortSignalAndTimeout(metadata?.abortSignal, timeoutMs)
 		const signal = mergeAbortSignals(internalController.signal, merged.signal)
 
-		this.options = { ...this.options, signal, _cleanup: merged.cleanup } as TOptions
+		this.options = { ...this.options, signal } as TOptions
+		this.cleanupFn = merged.cleanup
 		return this
 	}
 
+	/**
+	 * Get the cleanup function for resources created by addMergedSignal.
+	 *
+	 * @returns Cleanup function, or a no-op when no merged signal was added
+	 */
+	getCleanup(): () => void {
+		return this.cleanupFn
+	}
+
 	/**
 	 * Set a single option by key (type-safe).
 	 *