feat: print `Listening on` messages on stderr instead of stdout (#25491)

Fixes https://github.com/denoland/deno/issues/25114

---------

Signed-off-by: Leo Kettmeir <crowlkats@toaxl.com>
Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: crowlkats <crowlkats@toaxl.com>
Co-authored-by: Nathan Whitaker <17734409+nathanwhit@users.noreply.github.com>

4 files changed, 18 insertions, 16 deletions

diff --git a/tests/integration/serve_tests.rs b/tests/integration/serve_tests.rs
index c34b0e286..a1df7825d 100644
--- a/tests/integration/serve_tests.rs
+++ b/tests/integration/serve_tests.rs
@@ -61,11 +61,13 @@ impl ServeClientBuilder {
   fn new() -> Self {
     Self(
       util::deno_cmd()
+        .env("NO_COLOR", "1")
         .current_dir(util::testdata_path())
         .arg("serve")
         .arg("--port")
         .arg("0")
-        .stdout_piped(),
+        .stdout_piped()
+        .stderr_piped(),
       None,
     )
   }
@@ -106,12 +108,12 @@ impl ServeClient {
   fn output(self) -> String {
     let mut child = self.child.borrow_mut();
     child.kill().unwrap();
-    let mut stdout = child.stdout.take().unwrap();
+    let mut stderr = child.stderr.take().unwrap();
     child.wait().unwrap();
 
     let mut output_buf = self.output_buf.borrow_mut();
 
-    stdout.read_to_end(&mut output_buf).unwrap();
+    stderr.read_to_end(&mut output_buf).unwrap();
 
     String::from_utf8(std::mem::take(&mut *output_buf)).unwrap()
   }
@@ -128,7 +130,7 @@ impl ServeClient {
     let mut buffer = self.output_buf.borrow_mut();
     let mut temp_buf = [0u8; 64];
     let mut child = self.child.borrow_mut();
-    let stdout = child.stdout.as_mut().unwrap();
+    let stderr = child.stderr.as_mut().unwrap();
     let port_regex = regex::bytes::Regex::new(r":(\d+)").unwrap();
 
     let start = std::time::Instant::now();
@@ -141,7 +143,7 @@ impl ServeClient {
           String::from_utf8_lossy(&buffer)
         );
       }
-      let read = stdout.read(&mut temp_buf).unwrap();
+      let read = stderr.read(&mut temp_buf).unwrap();
       buffer.extend_from_slice(&temp_buf[..read]);
       if let Some(p) = port_regex
         .captures(&buffer)
diff --git a/tests/integration/watcher_tests.rs b/tests/integration/watcher_tests.rs
index 2590e79d6..27c59a27d 100644
--- a/tests/integration/watcher_tests.rs
+++ b/tests/integration/watcher_tests.rs
@@ -1359,16 +1359,16 @@ async fn test_watch_serve() {
     .piped_output()
     .spawn()
     .unwrap();
-  let (mut stdout_lines, mut stderr_lines) = child_lines(&mut child);
+  let (mut _stdout_lines, mut stderr_lines) = child_lines(&mut child);
 
-  wait_contains("Listening on", &mut stdout_lines).await;
+  wait_contains("Listening on", &mut stderr_lines).await;
   // Note that we start serving very quickly, so we specifically want to wait for this message
   wait_contains(r#"Watching paths: [""#, &mut stderr_lines).await;
 
   file_to_watch.write(file_content);
 
   wait_contains("serving", &mut stderr_lines).await;
-  wait_contains("Listening on", &mut stdout_lines).await;
+  wait_contains("Listening on", &mut stderr_lines).await;
 
   check_alive_then_kill(child);
 }
diff --git a/tests/testdata/serve/parallel.ts b/tests/testdata/serve/parallel.ts
index f1f118c71..2ba7ccfca 100644
--- a/tests/testdata/serve/parallel.ts
+++ b/tests/testdata/serve/parallel.ts
@@ -1,7 +1,7 @@
-console.log("starting serve");
+console.error("starting serve");
 export default {
   fetch(_req: Request) {
-    console.log("serving request");
+    console.error("serving request");
     return new Response("deno serve parallel");
   },
 };
diff --git a/tests/unit/serve_test.ts b/tests/unit/serve_test.ts
index 4a19d8df2..c1e217a11 100644
--- a/tests/unit/serve_test.ts
+++ b/tests/unit/serve_test.ts
@@ -792,8 +792,8 @@ Deno.test(
   async function httpServerDefaultOnListenCallback() {
     const ac = new AbortController();
 
-    const consoleLog = console.log;
-    console.log = (msg) => {
+    const consoleError = console.error;
+    console.error = (msg) => {
       try {
         const match = msg.match(
           /Listening on http:\/\/(localhost|0\.0\.0\.0):(\d+)\//,
@@ -818,7 +818,7 @@ Deno.test(
 
       await server.finished;
     } finally {
-      console.log = consoleLog;
+      console.error = consoleError;
     }
   },
 );
@@ -875,8 +875,8 @@ Deno.test({ permissions: { net: true } }, async function ipv6Hostname() {
   const ac = new AbortController();
   let url = "";
 
-  const consoleLog = console.log;
-  console.log = (msg) => {
+  const consoleError = console.error;
+  console.error = (msg) => {
     try {
       const match = msg.match(/Listening on (http:\/\/(.*?):(\d+)\/)/);
       assert(!!match, `Didn't match ${msg}`);
@@ -897,7 +897,7 @@ Deno.test({ permissions: { net: true } }, async function ipv6Hostname() {
     assert(new URL(url), `Not a valid URL "${url}"`);
     await server.shutdown();
   } finally {
-    console.log = consoleLog;
+    console.error = consoleError;
   }
 });