[PATCH 0/4] a few mark_parents_uninteresting cleanups

This is a follow-up to the discussion from February:

  https://public-inbox.org/git/1519522496-73090-1-git-send-email-dstolee@microsoft.com/

There I theorized that some of these extra has_object_file() checks were unnecessary. After poking around a bit, I've convinced myself that this is the case, so here are some patches.

After Stolee's fix in ebbed3ba04 (revision.c: reduce object database queries, 2018-02-24), I doubt this will provide any noticeable speedup. IMHO the value is just in simplifying the logic.

The first two patches are the actual has_object_file simplifications. The second two are an attempt to fix some head-scratching I had while reading mark_parents_uninteresting(). I hope the result is easier to follow, but I may have just shuffled one confusion for another. :)

  [1/4]: mark_tree_contents_uninteresting(): drop missing object check
  [2/4]: mark_parents_uninteresting(): drop missing object check
  [3/4]: mark_parents_uninteresting(): replace list with stack
  [4/4]: mark_parents_uninteresting(): avoid most allocation

 revision.c | 90 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 50 insertions(+), 40 deletions(-)

-Peff