Improves kill-logic of child processes.

package.json

@@ -15,8 +15,8 @@
     "clean": "rimraf lib bin coverage",
     "lint": "eslint src test",
     "build": "npm run clean && npm run lint && babel src --out-dir . --optional runtime,asyncToGenerator",
-    "test": "npm run lint && babel-node node_modules/isparta/bin/isparta cover node_modules/mocha/bin/_mocha -- test/*.js --require scripts/mocha-babel-hook --timeout 30000",
-    "testing": "mocha test/*.js --require scripts/mocha-babel-hook --timeout 30000 --watch --growl",
+    "test": "npm run lint && babel-node node_modules/isparta/bin/isparta cover node_modules/mocha/bin/_mocha -- test/*.js --require scripts/mocha-babel-hook --timeout 12000",
+    "testing": "mocha test/*.js --require scripts/mocha-babel-hook --timeout 12000 --watch --growl",
     "coveralls": "cat coverage/lcov.info | coveralls"
   },
   "dependencies": {

src/lib/run-task.js

@@ -1,8 +1,8 @@
-import {spawn} from "child_process";
 import {parse as parseArgs} from "shell-quote";
-import killTask from "./kill-task";
 import whichNpm from "./which-npm";
 
+const spawn = require(process.platform === "win32" ? "./spawn-win32" : "./spawn-posix");
+
 function detectStreamKind(stream, std) {
     return (
         stream == null ? "ignore" :
@@ -52,7 +52,8 @@ export default function runTask(task, stdin, stdout, stderr) {
 
     promise.abort = function abort() {
         if (cp != null) {
-            killTask(cp);
+            cp.kill();
+            cp = null;
         }
     };
 

src/lib/spawn-posix.js

@@ -0,0 +1,59 @@
+import cp from "child_process";
+
+// List of child processes that are running currently.
+const children = [];
+
+/**
+ * Removes this process from the children pool.
+ * @this ChildProcess
+ */
+function removeFromPool() {
+    const index = children.indexOf(this);
+    if (index !== -1) {
+        children.splice(index, 1);
+    }
+}
+
+/**
+ * Kills this process and sub processes with the process group ID.
+ * @this ChildProcess
+ */
+function kill() {
+    process.kill(-this.pid);
+}
+
+/**
+ * Launches a new process with the given command.
+ * This is almost same as `child_process.spawn`.
+ *
+ * This detaches the new process to make new process group.
+ * And if this process exited before the new process exits, this kills the new process.
+ *
+ * This returns a `ChildProcess` instance.
+ * `kill` method of the instance kills the new process and its sub processes with the process group ID.
+ *
+ * @param {string} command - The command to run.
+ * @param {string[]} args - List of string arguments.
+ * @param {object} options - Options.
+ * @returns {ChildProcess} A ChildProcess instance of new process.
+ */
+export default function spawn(command, args, options) {
+    options.detached = true; // eslint-disable-line no-param-reassign
+
+    const child = cp.spawn(command, args, options);
+    child.on("exit", removeFromPool);
+    child.on("error", removeFromPool);
+    child.kill = kill;
+
+    // Add to the pool to kill on exit.
+    children.push(child);
+
+    return child;
+}
+
+// Kill all child processes on exit.
+process.on("exit", () => {
+    for (const child of children) {
+        child.kill();
+    }
+});

src/lib/spawn-win32.js

@@ -0,0 +1,28 @@
+import cp from "child_process";
+
+/**
+ * Kills the new process and its sub processes forcibly.
+ * @this ChildProcess
+ */
+function kill() {
+    spawn("taskkill", ["/F", "/T", "/PID", this.pid]);
+}
+
+/**
+ * Launches a new process with the given command.
+ * This is almost same as `child_process.spawn`.
+ *
+ * This returns a `ChildProcess` instance.
+ * `kill` method of the instance kills the new process and its sub processes forcibly.
+ *
+ * @param {string} command - The command to run.
+ * @param {string[]} args - List of string arguments.
+ * @param {object} options - Options.
+ * @returns {ChildProcess} A ChildProcess instance of new process.
+ */
+export default function spawn(command, args, options) {
+    const child = cp.spawn(command, args, options);
+    child.kill = kill;
+
+    return child;
+}