fix(ext/fetch): include TCP src/dst socket info in error messages (#24939)

This commit makes `fetch` error messages include source and destination TCP
socket info i.e. port number and IP address for better debuggability.

Closes #24922

1 files changed, 50 insertions, 9 deletions

diff --git a/tests/unit/fetch_test.ts b/tests/unit/fetch_test.ts
index 5ebc0c86f..9b2463bcc 100644
--- a/tests/unit/fetch_test.ts
+++ b/tests/unit/fetch_test.ts
@@ -3,6 +3,7 @@ import {
   assert,
   assertEquals,
   assertRejects,
+  assertStringIncludes,
   assertThrows,
   delay,
   fail,
@@ -1977,14 +1978,24 @@ Deno.test(
     });
 
     const url = `http://localhost:${listenPort}/`;
-    const err = await assertRejects(
-      () =>
-        fetch(url, {
-          body: stream,
-          method: "POST",
-        }),
-      TypeError,
-      `error sending request for url (${url}): client error (SendRequest): error from user's Body stream`,
+    const err = await assertRejects(() =>
+      fetch(url, {
+        body: stream,
+        method: "POST",
+      })
+    );
+
+    assert(err instanceof TypeError, `err was ${err}`);
+
+    assertStringIncludes(
+      err.message,
+      "error sending request from 127.0.0.1:",
+      `err.message was ${err.message}`,
+    );
+    assertStringIncludes(
+      err.message,
+      ` for http://localhost:${listenPort}/ (127.0.0.1:${listenPort}): client error (SendRequest): error from user's Body stream`,
+      `err.message was ${err.message}`,
     );
 
     assert(err.cause, `err.cause was null ${err}`);
@@ -2066,7 +2077,7 @@ Deno.test("URL authority is used as 'Authorization' header", async () => {
 
 Deno.test(
   { permissions: { net: true } },
-  async function errorMessageIncludesUrlAndDetails() {
+  async function errorMessageIncludesUrlAndDetailsWithNoTcpInfo() {
     await assertRejects(
       () => fetch("http://example.invalid"),
       TypeError,
@@ -2074,3 +2085,33 @@ Deno.test(
     );
   },
 );
+
+Deno.test(
+  { permissions: { net: true } },
+  async function errorMessageIncludesUrlAndDetailsWithTcpInfo() {
+    const listener = Deno.listen({ port: listenPort });
+    const server = (async () => {
+      const conn = await listener.accept();
+      listener.close();
+      // Immediately close the connection to simulate a connection error
+      conn.close();
+    })();
+
+    const url = `http://localhost:${listenPort}`;
+    const err = await assertRejects(() => fetch(url));
+
+    assert(err instanceof TypeError, `${err}`);
+    assertStringIncludes(
+      err.message,
+      "error sending request from 127.0.0.1:",
+      `${err.message}`,
+    );
+    assertStringIncludes(
+      err.message,
+      ` for http://localhost:${listenPort}/ (127.0.0.1:${listenPort}): client error (SendRequest): `,
+      `${err.message}`,
+    );
+
+    await server;
+  },
+);