Enhance loop condition in URI.allLocations to prevent endless loops

[corneliusludmann]

Fixes #6377

What it does

This commit adds hasDir() in Path and extend the loop condition in URI.allLocations to prevent an endless loop. See #6377 for a detailed description of the problem and a discussion.

How to test

Execute

const allLocations = new URI().withScheme('foo').withPath('foobar.txt').allLocations;

will leads to an endless loop without this commit. After this commit it won't.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[akosyakov]

@corneliusludmann please add tests, see there is uri.spec.ts

[corneliusludmann]

@corneliusludmann please add tests, see there is uri.spec.ts

Done. See updated commit.

[akosyakov]

I think location.path.hasDir should not be necessary.

Since we cannot return undefined for path.dir, can we return an empty path instead? It would be aligned when with Node.js behaviour as it should be, i.e.

const path = require('path');
console.log(path.parse('foo'));

prints:

gitpod /workspace/theia $ node test.js 
{ root: '', dir: '', base: 'foo', ext: '', name: 'foo' }

[corneliusludmann]

Do you mean that Path#dir should return an empty string instead of this when there is no dir? If you mean that, then I would totally agree with you. In my opinion, that would be much more intuitive. I just wonder what the reason for returning this was in the first place … and if changing this would break something elsewhere.

[akosyakov]

I meant an empty path, i.e. something like new Path('').

My concern is that a loop like here should always terminate for any URI just by checking path.isRoot.

[akosyakov]

Sorry for the confusion, just spotted that i typed remove instead of return in the original comment.

[corneliusludmann]

And I meant empty path instead of empty string. :-D

I totally agree with you that an empty path instead of this makes more sense as return value. The same goes in my opinion for URI#parent, by the way. But this does not terminates the loop above. A path that is not absolute does not have a root at all and therefore asking for isRoot is not right here. Or am I wrong?

But the loop condition above can be abbreviated by just checking for hasDir because root never has a dir.

[akosyakov]

yes, I think you are right, let's go with this solution it does not seem to be breaking

[akosyakov]

thank you for catching it and adding more tests!