Fix for path.resolve containing relative path to another drive in windows

[ankurp]

Fixes #50

Issue can be reproduced by running path.resolve in Windows as such path.resolve('C:/some/random/path', '../../../../../D:/another/random/path'); This outputs c:\D:\another\random\path where d: drive is not considered absolute.

[rvagg]

thanks @ankurp, could you rebase this off v0.12 please, you have some additional commit noise in here from 8868378 which makes this hard to review, aim for just showing your commits (and before it's merged it needs to be just one commit but you can squash later)

[ankurp]

I just added upstream git remote add upstream https://github.com/iojs/io.js and did a pull from git pull upstream v0.12 and merged

[ankurp]

Seems like other people's commits got included. Is v0.12 the branch to pull from or master?

[indutny]

ok, you totally borked it out :)

git fetch upstream
git reset --hard upstream/v0.12
git cherry-pick 25e68db 1652761 1e42c96 143a03b
git push -f origin v0.12

Also I would recommend you to use feature branches next time, to ensure that this things won't happen. And do git fetch upstream && git rebase upstream/v0.12 or git pull --rebase upstream v0.12 instead of just git pull.

[ankurp]

Will do

[ankurp]

Done cherry picked only my changes.

[ankurp]

Can we merge this. I thought this fork was more active than nodejs

[bnoordhuis]

@ankurp This needs a review from a Windows developer, maybe @seishun or @piscisaureus.

To expedient matters, can you squash the commits and write a nice commit log? See CONTRIBUTING.md for an example. Thanks.

[seishun]

@ankurp '../../../../../D:/another/random/path' doesn't look like a valid path to me. Can you name an example where this works as you would expect?

[ankurp]

I am squashing the commits. I found this bug when generating sourcemaps for a web project and the files being imported in sass were on a different Windows drive. If you do a path.relative from one drive to another it will go up using ../ until it reaches My Computer and then go to the letter drive.

[ankurp]

@seishun Try this please in io.js path.relative("c:/some/dir", "d:/some/fold") and you will get ../../../d:/some/fold

[seishun]

This is a path.relative bug if anything. Relative path across drives doesn't make sense. See for example PathRelativePathTo: "On the other hand, "c:\FolderA\FolderB" and "a:\FolderA\FolderD do not share a common prefix, and the function will fail.".

[ankurp]

@seishun The relative path is correct as in the drives are mounted at the root in Windows. You can follow along the relative path and get to that folder in other drive. I have also squashed the commit and updated the PR.

[seishun]

the drives are mounted at the root in Windows.

There is no single "root" in Windows. My Computer is purely a Windows Explorer concept.

You can follow along the relative path and get to that folder in other drive.

Actually no, cd won't even let you change drives without a /D switch. cd .. at the root of a drive does nothing.

[ankurp]

Then the fix is to throw an error if someone tries to do relative path across drives?

[seishun]

That sounds sane to me. It's a good translation of returning FALSE from PathRelativePathTo.

[ankurp]

Ok let me change the PR then.

[piscisaureus]

-1.

..\..\c:\etc\bla is always in invalid path.
If a path operation turns an invalid path into a valid path, that's a disaster or security issue waiting to happen.
I think "garbage in, garbage out" is wildly more preferrable.

[ankurp]

OK then I will throw an exception if there are ../ in the path to another lettered drive.