Relative paths should be invalid

[alberto]

I think node-ignore should not filter relative paths starting with ./ or ../

const ignore = require('ignore');
var ig = ignore().add(['.*']);
ig.filter(['foo', '.bar', './baz', '../quuz']);

Outputs: [ 'foo' ]

Similarly, relative ignore paths should be discarded as invalid:

const ignore = require('ignore')
var ig = ignore().add(['../*'])
ig.filter(['foo', '.bar', './baz', '../quuz'])
[ 'foo', '.bar', './baz' ]

[kaelzhang]

Let's discuss this first.

1. relative paths like ../* should always be ignored.
2. relatvie paths like ./foo shoule be converted to foo first (or not?)
3. the conversion from ./foo -> foo should be done by user or by node-ignore?

path.join('./foo') // foo

[alberto]

Note you can do things like ./../foo so you are not guaranteed to always get a path in a subdirectory.

Ideally the conversion should by done by the user but node-ignore should not filter those if they don't, IMO.

Maybe you could try to get the relative path and exclude from filtering if they are outside the current directory, I don't know.

Here is another simplified example not mixing with relative ignore patters:

const ignore = require('ignore')
var ig = ignore().add(['foo.js'])
ig.filter(['foo.js', 'bar.js', '../foo.js'])

[ 'bar.js' ]

I don't think it should filter ../foo.js

[kaelzhang]

@alberto

I've tried to upgrade node-ignore to 5.x for eslint, but I found that it was harder than I expected.

There are lots of runtime logics that make node-ignore to filter relative paths in eslint, which I thought is not robust because node-ignore can not ensure idempotence for these cases.

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With ignore@5.0.2, if we filter a relative path such as ./foo or ../bar, there will be an error thrown.