support relative paths in linter + spans that span multiple characters/lines

[oli-obk]

previously the lints did not show up in files if the paths were relative. Alternatively this could be changed in atom-linter directly, but I don't think that's feasible as atom-linter doesn't know about projects, but atom-build explicitly does.

fixes #359

[noseglid]

The error match file/configuration is not necessarily in the first project. The path you're actually looking for here is in the variable p (determined at the top of this function).

[oli-obk]

addressed comments by fixing the appropriate commits

[noseglid]

What is the problem with relative paths? It works well for me:

Possibly it should be relative cwd instead? As that is the path that the error is most likely to be relative to.

[oli-obk]

the problem is that you don't get a hit on File only on Project. You can seen this at the bottom of the screen. With the changes implemented in this PR, you also get a squiggly line at the line+col location and a popup message showing the error message (if any). With the changes I made to cargo, you get a squiggly line below the entire error location (this can be applied to gcc errors and many others, too).

[noseglid]

Still something weird with the test: https://travis-ci.org/noseglid/atom-build/jobs/119506163

Also, I think it makes more sense to take it relative to the cwd of the executed command (rather than active project path).

[noseglid]

This will solve #359

[oli-obk]

Also, I think it makes more sense to take it relative to the cwd of the executed command (rather than active project path).

oh. that makes sense

[noseglid]

cwd is available in that scope, unless I am mistaken. So should be as easy as changing that

And the remaining failing spec probably has the same fix as the one you already corrected. (You can run specs locally in your Window: Run Package Specs). They require no setup.

[oli-obk]

changed to use cwd and fixed the test

[noseglid]

The slashes / in the specs should be backslashes \ on windows. Use path.join to get the correct delimiter.

[oli-obk]

travis and appveyor are happy now

[noseglid]

Very nice. Thanks for this!