Re: "git log --first-parent" shows parents that are not first

しらいしななこ  [off-list ref] writes:

quoted

The result given by "git log --first-parent" ('next' version) is
unexpected to me.

  % git rev-parse origin/next
  4eddac518225621c3e4f7285beb879d2b4bad38a
  % git log --abbrev-commit --pretty=oneline --first-parent origin/next^..origin/next
  4eddac5... Merge branch 'master' into next
  1f8115b... Merge branch 'maint'
...
  921177f... Documentation: improve "add", "pull" and "format-patch" examples
  c904bf3... Be more careful with objects directory permissions on clone

I asked for the log between one commit before the tip of "origin/next"
and the tip of the branch, following only the first-parent links.
v1.5.5 is not broken and shows the expected result:

  % ~/git-v1.5.5/bin/git log --abbrev-commit --pretty=oneline --first-parent origin/next^..origin/next
  4eddac5... Merge branch 'master' into next

Could you please revert d9c292e8bbd51c84cb9ecd86cb89b8a1b35a2a82?  With
that patch reverted from 'next', the problem disappears.

That's d9c292e (Simplify and fix --first-parent implementation,
2008-04-27) by Stephen.

I know that the alleged "fix" works around a corner-case, a fast-forward
situation that was artificually recorded as a merge, but if the "cure"
breaks a normal case like this, it is worse than the disease.

Stephen, do you have a fix?