Note that this slightly changes the order of lines in the output of
'git name-rev --all', usually swapping two lines every 35 lines in
git.git or every 150 lines in linux.git.  This shouldn't matter in
practice, because the output has always been unordered anyway.

I didn't verify that the changing of order is fine, but other than that,
this patch looks great.

This patch is best viewed with '--ignore-all-space'.

Thanks for the tip! I ended up unindenting the loop to see the changes
better, but I should have done this instead.

-static void name_rev(struct commit *commit,
+static void name_rev(struct commit *start_commit,
 		const char *tip_name, timestamp_t taggerdate,
 		int from_tag)

There are many changes from tip_name to name->tip_name in this function
that mean that tip_name is no longer used within this function. Should
this cleanup have been done in one of the earlier patches?

Apart from that, overall, this patch looks like a straightforward good
change. When we have a parent, instead of immediately calling name_rev()
recursively, we first add it to an array, and then (in reverse order)
add it to a priority queue which is actually used as a LIFO stack.