FileMerge quits immediately after launching from SourceTree

Question

I regularly use Atlassian SourceTree (on Mac OS X) to launch FileMerge to resolve git merge conflicts. Out of the blue it has stopped working: when I right click and select

Answer 1

For me, SourceTree didn't even launch FileMerge. When clicking Launch External Merge Tool nothing happened.

Moreover, running opendiff in Terminal worked as expected:

$ opendiff
opendiff[64176:5561154] too few arguments
opendiff[64176:5561154] usage: opendiff file1 file2 [-ancestor ancestorFile] [-merge mergeFile]

What helped me was manually configuring SourceTree to use FileMerge via the opendiff command with the following arguments: $LOCAL $REMOTE -ancestor $BASE -merge $MERGED

This way, SourceTree opens FileMerge as expected.