debugger: improve ESRCH error message

When using `iojs debug -p <pid>` with an invalid pid, the debugger
printed an internal error message because it wasn't smart enough
to figure out that the target process didn't exist.  Now it is.

PR-URL: https://github.com/nodejs/io.js/pull/1863
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Yosuke Furukawa <yosuke.furukawa@gmail.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/lib/_debugger.js b/lib/_debugger.js
index 4c503d2f5..83086ffb5 100644
--- a/lib/_debugger.js
+++ b/lib/_debugger.js
@@ -1639,7 +1639,16 @@ Interface.prototype.trySpawn = function(cb) {
   } else if (this.args.length === 3) {
     // `node debug -p pid`
     if (this.args[1] === '-p' && /^\d+$/.test(this.args[2])) {
-      process._debugProcess(parseInt(this.args[2], 10));
+      const pid = parseInt(this.args[2], 10);
+      try {
+        process._debugProcess(pid);
+      } catch (e) {
+        if (e.code === 'ESRCH') {
+          console.error(`Target process: ${pid} doesn't exist.`);
+          process.exit(1);
+        }
+        throw e;
+      }
       isRemote = true;
     } else {
       var match = this.args[1].match(/^--port=(\d+)$/);
@@ -1704,8 +1713,8 @@ Interface.prototype.trySpawn = function(cb) {
   function connectError() {
     // If it's failed to connect 10 times then print failed message
     if (connectionAttempts >= 10) {
-      self.stdout.write(' failed, please retry\n');
-      return;
+      console.error(' failed, please retry');
+      process.exit(1);
     }
     setTimeout(attemptConnect, 500);
   }