Thanks again to Ed Thomson’s Git for Visual Studio O’Reilly course! I searched for a solid hour how to manually configure VS as your external diff and merge tool. I knew I had seen it somewhere. Then I remembered Ed’s course!
Go to Team Explorer – Settings – Git – Global Settings. Then for either difftool or mergetool or both click Use Visual Studio
Suppose you have at least one commit and you’ve started making changes to that file in your working directory.
Now you can do
which will bring up a prompt asking you to confirm launching your external diff tool vsdiffmerge (the tool VS uses).
And now VS will launch and open with the diff tool showing the original Source (i.e. the file in the last commit) vs the changed file Target (the one you changed in the working directory)
BTW the reason why the tab is shown on the right side of the file tab channel in VS instead of the left is because this is a temporary file that isn’t listed Solution Explorer. Back in the day, you’d have to add this to the miscellaneous project, but not sure how that all works today. But I digress…. 🙂
So let’s see what the Use Visual Studio link did by using these two commands
$ git config diff.tool
$ git config difftool.vsdiffmerge.cmd
And the `difftool.vsdiffmerge.cmd` line is the magic line I was hunting the Internet for. Thanks Ed’s course!