[sourcetree / xcode] Merge tool (filemerge) opens then quits straight away

[0xdevalias]

Semi-related: #10

Running opendiff on the commandline (SourceTree's helper tool) reveals the following:

⇒  opendiff
xcode-select: error: tool 'opendiff' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

I found the fix here:

• https://stackoverflow.com/questions/32729049/filemerge-quits-immediately-after-launching-from-sourcetree/52221151#52221151

  • Tell system when Xcode utilities live:

    • xcode-select -switch /Applications/Xcode.app/Contents/Developer

  • Set "opendiff" as the default mergetool globally:

    • git config --global merge.tool opendiff

Which apparently originally came from:

• https://gist.github.com/kylefox/4512777

You can do a quick sanity check with opendiff again:

⇒  opendiff
2020-11-19 11:44:47.285 opendiff[90705:38075941] too few arguments
2020-11-19 11:44:47.290 opendiff[90705:38075941] usage: opendiff file1 file2 [-ancestor ancestorFile] [-merge mergeFile]

In this case, you're good to go!

It would be good to add this to the dotfiles so it's handled automagically on new system setup