fix(telegram): add EAFNOSUPPORT to local-socket-failure codes and add regression test

ZOOWH · ZOOWH · commit 1f4f55f98214 · 2026-06-19T06:52:44.000+08:00
LOCAL_SOCKET_FAILURE_MESSAGE_PATTERN extracts EAFNOSUPPORT from message text, but LOCAL_SOCKET_FAILURE_ERROR_CODES only contained EADDRNOTAVAIL. This mismatch meant a message-only EAFNOSUPPORT envelope would have ctx.codes non-empty without triggering the local-socket-failure guard, silently blocking the fallback without emitting the diagnostic warn — a classification gap that changes Telegram retry behavior. Add EAFNOSUPPORT to LOCAL_SOCKET_FAILURE_ERROR_CODES so the guard and message parser are aligned, and add a message-only EAFNOSUPPORT regression test asserting fallback=false and diagnostic warn emitted. Closes #94620
diff --git a/extensions/telegram/src/fetch.test.ts b/extensions/telegram/src/fetch.test.ts
@@ -1365,6 +1365,17 @@ describe("shouldRetryTelegramTransportFallback", () => {
     expectLoggerMessageContaining(loggerWarn, "local socket allocation failure");
   });
 
+  it("does not trigger IP-rotation fallback for EAFNOSUPPORT embedded only in the message", () => {
+    // EAFNOSUPPORT is also a local address-family failure — the kernel cannot
+    // assign a source address for the requested family. Like EADDRNOTAVAIL,
+    // rotating to an alternative Telegram IP cannot fix it.
+    const err = new TypeError("fetch failed: connect EAFNOSUPPORT 149.154.167.220:443 - Local (:::0)");
+
+    expect(shouldRetryTelegramTransportFallback(err)).toBe(false);
+    expectNoLoggerMessageContaining(loggerWarn, "fetch fallback: DNS-resolved IP unreachable");
+    expectLoggerMessageContaining(loggerWarn, "local socket allocation failure");
+  });
+
   it("still retries for remote-reachability errnos that IP rotation can fix", () => {
     const err = buildFetchFallbackError("EHOSTUNREACH");
     expect(shouldRetryTelegramTransportFallback(err)).toBe(true);
diff --git a/extensions/telegram/src/fetch.ts b/extensions/telegram/src/fetch.ts
@@ -131,7 +131,7 @@ const FALLBACK_RETRY_ERROR_CODES = [
 // IP cannot fix these (the kernel cannot assign a source address/port for any
 // destination), so falling back through the pinned-IP dispatcher is dead code
 // that only produces misleading "Telegram is down" log noise during an incident.
-const LOCAL_SOCKET_FAILURE_ERROR_CODES = ["EADDRNOTAVAIL"] as const;
+const LOCAL_SOCKET_FAILURE_ERROR_CODES = ["EADDRNOTAVAIL", "EAFNOSUPPORT"] as const;
 
 // Errno tokens may appear only inside the error `message` when undici wraps a
 // connect failure as `fetch failed` without propagating `.code` onto the cause
