With github pullrequests work on target repo rather than the source

[timor-raiman]

This provides support for private forks, where GITHUB_TOKEN generated by GH in the target repo pull request context does not provide access to the pull request's source repo.

This requires vcstool to be fixed to properly support checking out sources by hash, rather than a branch or tag, because a pull request's source branch does not exist in the destination repository. Rather, the patch can be accessed as refs/pr/123/head or refs/pr/123/merge. With github.context.sha being equivalent to the resolved commit hash of refs/pr/123/merge.

[Nir-Az]

Any change someone can take a look on this 2 PR's? It should fix the issues we see. Otherwise we cannot use this tool as our builds are failing.. Thanks

[codecov[bot]]

Codecov Report

Patch coverage has no change and project coverage change: -0.34 :warning:

Comparison is base (fc52906) 47.87% compared to head (907af1e) 47.53%.

:exclamation: Current head 907af1e differs from pull request most recent head d18eee4. Consider uploading reports for the commit d18eee4 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #816      +/-   ##
==========================================
- Coverage   47.87%   47.53%   -0.34%     
==========================================
  Files           2        2              
  Lines         282      284       +2     
  Branches       76       77       +1     
==========================================
  Hits          135      135              
- Misses        147      149       +2     

Impacted Files	Coverage Δ
src/action-ros-ci.ts	41.56% <0.00%> (-0.33%)	:arrow_down:

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[christophebedard]

The problem is that there is currently no active maintainer for vcstool. This will not get fixed without someone submitting a PR to the vcstool repo with a fix, but even then there is no active maintainer to merge it. I know people are trying to figure this out, but it might take a bit of time.

We could consider using a custom/forked version of vcstool with the fix needed for this in action-ros-ci itself, but then again someone needs to submit a fix.