Error: spawn psc ENOENT

[JohnGurin]

$ gulp
[12:05:33] Using gulpfile ~\Documents\Purescript\gulpfile.js
[12:05:33] Starting 'purescript'...
events.js:85
      throw er; // Unhandled 'error' event
            ^
Error: spawn psc ENOENT
    at exports._errnoException (util.js:746:11)
    at Process.ChildProcess._handle.onexit (child_process.js:1046:32)
    at child_process.js:1137:20
    at process._tickCallback (node.js:355:11)

//gulpfile.js
var gulp = require('gulp');
var purescript = require('gulp-purescript');

gulp.task('purescript', function(){
  return gulp.src('src/**/*.purs').
         pipe(purescript.psc({main:"Chapter2"})). //<-- if this line is commented the script works
         pipe(gulp.dest('build'));
});
gulp.task('default', ['purescript']);

-- Chapter2.purs
module Chapter2 where
import Debug.Trace
main = trace "Hello"

$ node -v
v0.12.1

$ npm -v
2.5.1

$ gulp -v
[12:05:49] CLI version 3.8.11
[12:05:49] Local version 3.8.11

#local node_modules
gulp\
gulp-dest\
gulp-purescript\
gulp-util\
logalot\
minimist\
multipipe\
resolve-bin\
through2\
which\

#this works
john@HOME-PC ~/Documents/Purescript
$ psc src/Chapter2.purs --output dist/Main.js --main=Chapter2 --module=Chapter2

Windows 8.1 x64

[ethul]

Thanks for the report. I haven't tried the library with node 0.12.x. I will take a look.

[garyb]

I'm using node 0.12.2 so I'm not necessarily sure it's related to that.

@JohnGurin what do you get for where psc?

[JohnGurin]

@garyb

john@HOME-PC ~/Documents/Purescript
$ where psc
c:\Users\john\AppData\Roaming\npm\psc
c:\Users\john\AppData\Roaming\npm\psc.cmd

[ethul]

Could the issue be:
https://github.com/npm/npm/wiki/Troubleshooting#error-enoent-stat-cusersuserappdataroamingnpm-on-windows-7

[JohnGurin]

So, I think I found the problem. http://stackoverflow.com/a/17537559
Made the gulp-purescript work by adding

// node_modules\gulp-purescript\index.js line:2196
function spawnFn(command, args, errback, callback) {
      command = command + ".cmd";  //<-- added this line
      return function(){
        var child_process = __webpack_require__(35);
        var process = child_process.spawn(command, args);
...

Now the gulp compiles *.purs to psc.js ignoring options

[ethul]

@JohnGurin thanks for digging into this.

I wonder if we are running into nodejs/node-v0.x-archive#2318

From that thread, it looks like one solution is to drop-in the following replacement for spawn.
https://github.com/IndigoUnited/node-cross-spawn

Would you possibly be able to try this module locally to see if it solves the problem (without adding the .cmd extension)? Sorry that I can't give this a go myself. I don't have access to windows at all.

Not sure if this is the best way to go, but might be worth a try.

[JohnGurin]

// node_modules\gulp-purescript\index.js line:2196
function spawnFn(command, args, errback, callback) {
      command = command + ".cmd";  //<-- added this line
      return function(){
        //var child_process = __webpack_require__(35);
        //var process = child_process.spawn(command, args);
           console.log(command);
        var process = require('cross-spawn')(command, args); //<-- added this line
...

results in the same as in previous attempt: gulp works but purescript.psc(options) options is not respected.

[ethul]

Thanks for giving this a try @JohnGurin

Did you happen to try it without adding the .cmd to command? I.e., removing:

command = command + ".cmd";  //<-- added this line

So it would be

// node_modules\gulp-purescript\index.js line:2196
function spawnFn(command, args, errback, callback) {
      return function(){
        //var child_process = __webpack_require__(35);
        //var process = child_process.spawn(command, args);
        var process = require('cross-spawn')(command, args); //<-- added this line
...

If this does not work as well, what are the options passed to psc? Can you please provide the values of command and args?

Thanks for all of this!

[JohnGurin]

gulp.task('purescript', function(){
  return gulp.src('src/**/*.purs').
         pipe(purescript.psc({noPrelude:true,main:'Chapter2',module:'Chapter2'})).
         pipe(gulp.dest('build'));
});

Sorry, I tested without command = command + ".cmd";, copy pasted it from previous message and missed the line.
console.log(command) prints psc

[ethul]

Ah, no worries. Thanks for the info. Just for good measure, would you mind console.log-ing the command and args variables and providing the output? I.e., the precise values passed to cross-spawn.

Thanks!

[JohnGurin]

function spawnFn(command, args, errback, callback) {
     return function(){
        //var child_process = __webpack_require__(35);
        //var process = child_process.spawn(command, args);
        console.log(command);
        console.log(args);
        var process = require('cross-spawn')(command, args);
...

john@HOME-PC ~/Documents/Purescript
$ gulp purescript
[19:03:52] Using gulpfile ~\Documents\Purescript\gulpfile.js
[19:03:52] Starting 'purescript'...
psc
[ 'C:\\Users\\john\\Documents\\Purescript\\src\\Chapter2.purs' ]
[19:03:52] Finished 'purescript' after 407 ms

[ethul]

Interesting. The value of args looks to be missing your options passed to psc in the gulpfile.

Perhaps cross-spawn is working properly, but somewhere outside of spawnFn the options are getting lost. I will look into this further, but if you have a chance to trace back the args value a bit to see where they might be getting lost, it would be a great help!

[JohnGurin]

// node_modules\gulp-purescript\index.js line:191
var psc = function (opts) {
        console.log(opts); //<--
            var run = function (i) {
            var _1330 = GulpPurescript_Options.pscOptionsNoOutput(opts);
        console.log(_1330); //<--
            return Prelude["<$>"]/*...*/(_1330.value0)))(/*...*/)(_1330.value1)));
        };
        return Prelude["<*>"]/*...*/(run));
    };

john@HOME-PC ~/Documents/Purescript
$ gulp purescript
[19:33:57] Using gulpfile ~\Documents\Purescript\gulpfile.js
[19:33:57] Starting 'purescript'...
{ noPrelude: true, main: 'Chapter2', module: 'Chapter2' }
{ value0: {}, value1: [] }
[19:33:57] Finished 'purescript' after 424 ms

btw, what is the right way to traceback nodejs?

[ethul]

Thanks!

What version of gulp-purescript are you on? Can you please try this with 0.4.2?

There was a previous fix (#24) for parsing the psc main option. Maybe an update will solve the options issue. If so, I can migrate to using cross-spawn.

And the way you traced is how I would have done it. Not sure if there is a better way.