fix: if no ps, walk /proc to kill child fully

Originally used ps-tree which relied on `ps` on *nix. But if the system
didn't have `ps` at all, we'd try to kill the child process, but alas
this would not always work, as we're spawning `sh` and _then_ node, so
the kill would only kill the `sh` process, and not the running node
process.

The new @remy/pstree lib sniffs for `ps` and defers to ps-tree,
otherwise it will walk /proc and map the PPID to the child process
allowing nodemon to fully clean up.

Author: remy

lib/monitor/run.js

@@ -11,17 +11,9 @@ var child = null; // the actual child process we spawn
 var killedAfterChange = false;
 var noop = function () { };
 var restart = null;
-var psTree = require('ps-tree');
-var hasPS = true;
+var psTree = require('@remy/pstree');
 var path = require('path');
 
-// discover if the OS has `ps`, and therefore can use psTree
-exec('ps', function (error) {
-  if (error) {
-    hasPS = false;
-  }
-});
-
 function run(options) {
   var cmd = config.command.raw;
 
@@ -291,23 +283,17 @@ function kill(child, signal, callback) {
     exec('taskkill /pid ' + child.pid + ' /T /F');
     callback();
   } else {
-    if (hasPS) {
-      // we use psTree to kill the full subtree of nodemon, because when
-      // spawning processes like `coffee` under the `--debug` flag, it'll spawn
-      // it's own child, and that can't be killed by nodemon, so psTree gives us
-      //  an array of PIDs that have spawned under nodemon, and we send each the
-      //   configured signal (defaul: SIGUSR2) signal, which fixes #335
-      psTree(child.pid, function (err, kids) {
-        spawn('kill', ['-s', signal, child.pid].concat(kids.map(function (p) {
-          return p.PID;
-        }))).on('close', callback);
-      });
-    } else {
-      exec('kill -s ' + signal + ' ' + child.pid, function () {
-        // ignore if the process has been killed already
-        callback();
-      });
-    }
+    // we use psTree to kill the full subtree of nodemon, because when
+    // spawning processes like `coffee` under the `--debug` flag, it'll spawn
+    // it's own child, and that can't be killed by nodemon, so psTree gives us
+    // an array of PIDs that have spawned under nodemon, and we send each the
+    // configured signal (default: SIGUSR2) signal, which fixes #335
+    // note that psTree also works if `ps` is missing by looking in /proc
+    psTree(child.pid, function (err, kids) {
+      spawn('kill', ['-s', signal, child.pid].concat(kids.map(function (p) {
+        return p.PID;
+      }))).on('close', callback);
+    });
   }
 }
 

package-lock.json

@@ -52,13 +52,13 @@
     "should": "~4.0.0"
   },
   "dependencies": {
+    "@remy/pstree": "^1.0.0",
     "chokidar": "^1.7.0",
     "debug": "^2.6.8",
     "es6-promise": "^3.3.1",
     "ignore-by-default": "^1.0.1",
     "lodash.defaults": "^3.1.2",
     "minimatch": "^3.0.4",
-    "ps-tree": "^1.1.0",
     "touch": "^3.1.0",
     "undefsafe": "0.0.3",
     "update-notifier": "^2.3.0"