Prevents child_process.exec timeouts from throwing when the child was previously killed.

lib/child_process.js

@@ -62,14 +62,23 @@ exports.execFile = function (file /* args, options, callback */) {
   var stderr = "";
   var killed = false;
 
+  function kill(){
+    if (killed) return;
+    try {
+      child.kill(options.killSignal);
+    } catch (err) {
+      if ("No such process" !== err.message) {
+        throw err;
+      }
+    }
+    killed = true;
+  }
+
   var timeoutId;
   if (options.timeout > 0) {
     timeoutId = setTimeout(function () {
-      if (!killed) {
-        child.kill(options.killSignal);
-        killed = true;
+      kill();
       timeoutId = null;
-      }
     }, options.timeout);
   }
 
@@ -78,30 +87,29 @@ exports.execFile = function (file /* args, options, callback */) {
 
   child.stdout.addListener("data", function (chunk) {
     stdout += chunk;
-    if (!killed && stdout.length > options.maxBuffer) {
-      child.kill(options.killSignal);
-      killed = true;
+    if (stdout.length > options.maxBuffer) {
+      kill();
     }
   });
 
   child.stderr.addListener("data", function (chunk) {
     stderr += chunk;
-    if (!killed && stderr.length > options.maxBuffer) {
-      child.kill(options.killSignal);
-      killed = true;
+    if (stderr.length > options.maxBuffer) {
+      kill();
     }
   });
 
   child.addListener("exit", function (code, signal) {
     if (timeoutId) clearTimeout(timeoutId);
+    if (!callback) return;
     if (code === 0 && signal === null) {
-      if (callback) callback(null, stdout, stderr);
+      callback(null, stdout, stderr);
     } else {
       var e = new Error("Command failed: " + stderr);
       e.killed = killed;
       e.code = code;
       e.signal = signal;
-      if (callback) callback(e, stdout, stderr);
+      callback(e, stdout, stderr);
     }
   });
 

test/simple/test-exec.js

@@ -35,12 +35,23 @@ exec("ls /DOES_NOT_EXIST", function (err, stdout, stderr) {
   }
 });
 
-exec("sleep 10", { timeout: 50 }, function (err, stdout, stderr) {
+exec("sleep 3", { timeout: 50 }, function (err, stdout, stderr) {
   assert.ok(err);
   assert.ok(err.killed);
   assert.equal(err.signal, 'SIGKILL');
 });
 
+
+var killMeTwice = exec("sleep 3", { timeout: 1000 }, function killMeTwiceCallback(err, stdout, stderr) {
+  assert.ok(err);
+  assert.ok(err.killed);
+  assert.equal(err.signal, 'SIGTERM');
+});
+process.nextTick(function(){
+  killMeTwice.kill();
+});
+
+
 exec('python -c "print 200000*\'C\'"', { maxBuffer: 1000 }, function (err, stdout, stderr) {
   assert.ok(err);
   assert.ok(err.killed);