refactor(telegram): avoid double-wrapping proxy fetch

src/telegram/fetch.test.ts

@@ -1,4 +1,5 @@
 import { afterEach, describe, expect, it, vi } from "vitest";
+import { resolveFetch } from "../infra/fetch.js";
 import { resetTelegramFetchStateForTests, resolveTelegramFetch } from "./fetch.js";
 
 const setDefaultAutoSelectFamily = vi.hoisted(() => vi.fn());
@@ -29,14 +30,59 @@ describe("resolveTelegramFetch", () => {
   it("returns wrapped global fetch when available", async () => {
     const fetchMock = vi.fn(async () => ({}));
     globalThis.fetch = fetchMock as unknown as typeof fetch;
+
     const resolved = resolveTelegramFetch();
+
     expect(resolved).toBeTypeOf("function");
+    expect(resolved).not.toBe(fetchMock);
   });
 
-  it("prefers proxy fetch when provided", async () => {
-    const fetchMock = vi.fn(async () => ({}));
-    const resolved = resolveTelegramFetch(fetchMock as unknown as typeof fetch);
+  it("wraps proxy fetches and normalizes foreign signals once", async () => {
+    let seenSignal: AbortSignal | undefined;
+    const proxyFetch = vi.fn(async (_input: RequestInfo | URL, init?: RequestInit) => {
+      seenSignal = init?.signal as AbortSignal | undefined;
+      return {} as Response;
+    });
+
+    const resolved = resolveTelegramFetch(proxyFetch as unknown as typeof fetch);
     expect(resolved).toBeTypeOf("function");
+
+    let abortHandler: (() => void) | null = null;
+    const addEventListener = vi.fn((event: string, handler: () => void) => {
+      if (event === "abort") {
+        abortHandler = handler;
+      }
+    });
+    const removeEventListener = vi.fn((event: string, handler: () => void) => {
+      if (event === "abort" && abortHandler === handler) {
+        abortHandler = null;
+      }
+    });
+    const fakeSignal = {
+      aborted: false,
+      addEventListener,
+      removeEventListener,
+    } as AbortSignal;
+
+    if (!resolved) {
+      throw new Error("expected resolved proxy fetch");
+    }
+    await resolved("https://example.com", { signal: fakeSignal });
+
+    expect(proxyFetch).toHaveBeenCalledOnce();
+    expect(seenSignal).toBeInstanceOf(AbortSignal);
+    expect(seenSignal).not.toBe(fakeSignal);
+    expect(addEventListener).toHaveBeenCalledTimes(1);
+    expect(removeEventListener).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not double-wrap an already wrapped proxy fetch", async () => {
+    const proxyFetch = vi.fn(async () => ({ ok: true }) as Response) as unknown as typeof fetch;
+    const alreadyWrapped = resolveFetch(proxyFetch);
+
+    const resolved = resolveTelegramFetch(alreadyWrapped);
+
+    expect(resolved).toBe(alreadyWrapped);
   });
 
   it("honors env enable override", async () => {

src/telegram/proxy.ts

@@ -1,5 +1,4 @@
 import { ProxyAgent, fetch as undiciFetch } from "undici";
-import { wrapFetchWithAbortSignal } from "../infra/fetch.js";
 
 export function makeProxyFetch(proxyUrl: string): typeof fetch {
   const agent = new ProxyAgent(proxyUrl);
@@ -10,5 +9,7 @@ export function makeProxyFetch(proxyUrl: string): typeof fetch {
       ...(init as Record<string, unknown>),
       dispatcher: agent,
     }) as unknown as Promise<Response>) as typeof fetch;
-  return wrapFetchWithAbortSignal(fetcher);
+  // Return raw proxy fetch; call sites that need AbortSignal normalization
+  // should opt into resolveFetch/wrapFetchWithAbortSignal once at the edge.
+  return fetcher;
 }