Provide source file path for tasks in gulp --tasks-json output

[segrey]

This information would be very useful in IDE integrations that allow to navigate from gulp tasks in a tree to their definitions in code.
If all gulp tasks are defined in a single gulpfile, there are no problems.
The problems arise where gulp tasks are spreaded among several gulpfiles. All IDEs can do in this situation is to use some sort of static analysis that determines all files required from the main gulpfile, i.e. the files where gulp tasks might be defined in. Unfortunately, static analysis fails sometimes, e.g. in case of an app generated with yo gulp-angular.

It'd be nice to have JSON output like this:

[
...
  {
    "label": "hello",
    "type": "task",
    "sourceFilePath": "/path/to/my.js", #
  }
...
]

/path/to/my.js

var gulp = require('gulp');
gulp.task('hello', function(){});

Thanks.

[yocontra]

Err... technically possible to do in undertaker (track what line of code called undertaker.add) by abusing the Error class and stackFrame overrides. @phated ?

[phated]

I don't think this is a good idea because in gulp 4, it is not recommended to break up gulpfiles in this fashion (all your functions should be exported and gulp.task should only be called in the gulpfile)

[segrey]

Didn't know about this. However, it's still possible to break up gulpfiles even it is not recommended to.
@phated Is there a page describing the recommendation?

[phated]

@segrey Sorry I haven't been able to write something up for this yet. Basically, the recommended pattern is going to be to export functions from your task modules, require them all in the top-level gulpfile and make all of your gulp.task/series/parallel calls in that gulpfile. I feel this is the ultimate reusability story (functions could be used anywhere, even outside gulp) and avoids the forward referencing problem, etc.

[segrey]

@phated Thanks for the info, I see. That would be more reusable indeed. However, if I understand correctly, nothing would prevent from tasks splitting? I mean probably there will be fewer examples of tasks split across multiple files, but who knows may be some new project template/generator will exploit such a capability.
JFYI: WebStorm 11 will have support for require-dir (https://youtrack.jetbrains.com/issue/WEB-18229). That lowers this issue's severity for WebStorm, but still it's just a static analysis, that can (and most likely will) fail for more complex examples.
We can close this issue for now. If there are some real gulp 4 examples having tasks split across multiple files, we can reopen it then?

[phated]

@segrey I started looking into this and have a WIP branch at https://github.com/gulpjs/undertaker/tree/sourceFilePath - can you take a look at the implementation and test output to see if it is what you are looking for? The main caveat I ran into was: when using an unregister (with gulp.task) function in a series/parallel chain, I set the sourceFilePath to null because it wasn't ever passed through the callsite machinery

[phated]

Deferring to gulp-cli 1.2.0

[yocontra]

@phated BTW, this code should do the trick https://github.com/TooTallNate/node-bindings/blob/master/bindings.js#L102

[phated]

Moved to gulpjs/gulp-cli#74