Improve source pattern handling

[novemberborn]

Watch mode lets you configure which source files should be watched. Certain directories are ignored by default, using https://github.com/novemberborn/ignore-by-default. Currently if you use a negation pattern in --source it stops ignoring those default directories. This is annoying as you'll have to repeat them manually.

It would be good to stop one of those default directories from being ignored. Then we could let you specify a negation pattern without disabling all default ignore patterns.

You can find the current logic at https://github.com/sindresorhus/ava/blob/1868204c1901f45b4f66a520ef6486fdd71fe1d2/lib/watcher.js#L273:L276.

[novemberborn]

Perhaps !!node_modules/**/* can be used to disable the !node_modules/**/* pattern. Then we change the aforementioned logic to include the remaining patterns.

[sindresorhus]

@novemberborn I don't think we should invent our own glob patterns.

Currently if you use a negation pattern in --source it stops ignoring those default directories.

Why?

I'm failing to see the problem here. Maybe provide an example?

[novemberborn]

Hmm. The problem may be different actually. We should be able to merge the ignore patterns. However it should be possible to override a pattern.

For example you might want to treat a dependency as a source so you can more easily debug that dependency and it's impact on your own project. I'll need to verify whether adding node_modules/somedependency/**/*.js works or whether !node_modules/**/* overrides it. Will update the issue.

[novemberborn]

#730 ensures that:

• You can specify negated patterns without having to declare the default exclusion patterns
• You can override the default exclusion patterns. E.g. specifying node_modules/some_dir/**/* will select that directory as a source, while the default exclusion pattern node_modules/**/* remains in effect