EventEmitter memory leak

[roymiloh]

This error appears whenever I use gulp-mocha with a watcher (memory increases per mocha.run), with mocha's cli (mocha --watch) it does not seem to reproduce.

I've tried the current pull requests - it's still happing. The cli itself handles watch a slightly different, haven't checked; anyway, it looks like a critical bug.

An example could be any suit case, it just increases as mocha.run() is called. Any ideas?

[roymiloh]

Well, it was smth with babel's require hook, which I pass as a plugin to mocha mocha({ require: ['babel-register'] }), I may imagine why it didn't work; would you consider it as a bug?

Anyway, the memory still increases, but less then before. I've checked with mocha --watch and it increases as well, but less then the current gulp-mocha plugin, for any reason.

It looks like it's smth with require.cache, no matter if require.cache length is the same after running the tests, the heap keeps growing. A reference nodejs/node-v0.x-archive#6176.

UPDATE:
After further investigation, as it looks now, it deletes redundant files from the cache. Mocha deletes files it watches, which are the specs themselves and some other src files in the "current working module". However, this looks "slightly" different (:flushed:), which makes the heap (extremely) growing up because delete require.cache[...] doesn't really freeing things, as referenced before.

We can ignore files from node_modules from being deleted and it will work fine.

@Jameskmonger, wdyt?

[sindresorhus]

Should be fixed in the latest release: https://github.com/sindresorhus/gulp-mocha/releases/tag/v4.0.0