fix parsing of windows file paths into a URI

[jakemac53]

Fixes Dart-Code/Dart-Code#3626

[jakemac53]

I didn't add tests here but I did manually test - I have #1612 out separately to try and get better windows test coverage generally (we have tests for this they just don't run on windows).

[jakemac53]

Ah crap this won't work because now the query params etc aren't allowed :(.

We might just end up needing to manually convert \ to / or something...

[jakemac53]

Talked with @natebosch offline and we decided to just check for a ? in the path and only try to parse it as a URI in that case.

[DanTup]

we decided to just check for a ? in the path and only try to parse it as a URI in that case.

Is this documented? It could be nice if it goes down the URI route then fails to find the file and there's a \ in the path, make the message more helpful (eg. explicitly call out that when using query strings the paths must be URIs using forward slashes).

It could be easy for tool authors that don't use Windows to ship code not realising this and it only fail for their users, so having a really clear message might same some debugging.

[jakemac53]

Is this documented? It could be nice if it goes down the URI route then fails to find the file and there's a \ in the path, make the message more helpful (eg. explicitly call out that when using query strings the paths must be URIs using forward slashes).

I did add an explicit message for that case - https://github.com/dart-lang/test/pull/1611/files#diff-dc50945ce4dcf38563b0434145591a7d37ff5007d90063c048ccefd867bcd9cdR183.

It probably wouldn't hurt to update the docs for the feature to call that out as well though.