git - Can gitk show the diff of merges by default?

Question

Currently for merges without conflicts gitk shows no diffs. Is it possible to have the diffs resulting from a merge (which are indeed there, e.g. git diff HEAD~1 after the merge shows these diffs) shown by defautl, e.g. using a command line switch? Or why does gitk by default not show them?

Answer 1

By default gitk does the same thing as the --cc option to git diff and compresses the merge to only show diff chunks that don't come directly from one or other parent. This is usually more helpful as conflicts are the interesting part of merges, the other parts of the diff will already appear in the diffs for the commits that made up the branch which was merged in.

The easiest way to view the full diff between a parent of a merge and the merge commit is to select the parent (normal click) and from the context menu on the merge commit (right/alternate click menu) select "Diff selected -> this".