Thursday, February 2, 2017

Fixing Merge conflicts in VS Code projects and VSTS (Visual Studio Online) repos

I use a combination of GitHub and Visual Studio Team Services (Visual Studio Online, VSTS, etc) repositories. GitHub is pretty straight forward for resolving merge conflicts of pull requests through it's online portal. Typically when I have come across merge conflicts in my VSTS repositories it has been with Visual Studio projects and so I could resolve them with the VS GUI. However I recently experienced a merge conflict with a pull request for one of my VSTS repositories where the code was written in Visual Studio Code. For working with the VSTS GIT repo I use the posh-git which comes with the GitHub Desktop install, but the logic here should transfer.

The situation I faced was that I had been working in a branch and editing a file, which had also been edited by a colleague in the master branch (I know, I know...). So when I pushed my changes from my local repo to VSTS and then used the web portal to create a Pull Request to merge the changes back into the master branch I received an error that there was a merge conflict blocking the pull request.


As I mentioned normally in this situation I am use to there being options provided to select which file/change you want to be kept. In VSTS i was not able to find any such option, and all articles online seemed to indicate how to fix this in Visual Studio GUI. While I do have VS installed I didn't want to use that as I am trying to just move to using VS Code and GIT command line where possible. I never did think to try the git menus in VS Code, or the GIT GUI..... and to be honest there is probably a better way to resolve this but this is how I resolved the conflict.

First I abandoned the Pull Request using the button in the screen shot above.

Next I ran git status to make sure that the "working tree is clean"

Then by looking at the history of the file in the VSTS portal within my branch, I tracked down the original commit id that the file was initialised with. Taking that identifier I ran git reset InitialCommitId PathToFile (e.g. git reset e99a################################c60 XML\9.xml

Now when you run git status it should so the file is unstaged. It will also show that there are changes for the same file to be committed. We need to discard the changes in the working directory (resetting it to the initial version the branch was created from). So run git checkout -- XML\9.xml

Now git status should show a change to be committed. Commit the change with git commit -m "description"

Your working directory should now show it is ahead of the origin branch, so push the changes upstream with git push.

Now your branch in VSTS does not contain any conflicts. I wasn't able to reactivate the existing pull request and have it succeed (it still showed the conflict), so I created a new fresh pull request for the branch and it was no longer blocked by a merge conflict.

Hopefully this helps others. If you have other suggestions on working around this please comment below.

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