patch, 5 partsTreat D/F conflict entry more carefully in unpack-trees.c::threeway_merge()

This fixes three buglets in threeway_merge() regarding D/F conflict entries.

* After finishing with path D and handling path D/F, some stages
  have D/F conflict entry which are obviously non-NULL.  For the
  purpose of determining if the path D/F is missing in the
  ancestor, they should not be taken into account.

* D/F conflict entry is a phony entry and does not record the
  path being processed, so do not pick up the name from there.

* D/F conflict entry is a marker to say "this stage does _not_
  have the path", so do not send them to keep_entry().

There might be more glitches, but I am slowly digging this mess through, which unfortunately was made even more work since merge-recursive is a built-in now.

Signed-off-by: Junio C Hamano <junkio@cox.net>
---
 unpack-trees.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

On Sat, 7 Apr 2007, Junio C Hamano wrote:

This bit is unnecessary, because the first bit means we treat D/F conflict as missing in that conditional, and don't count it as an entry at all, let alone one with a useful name.

Looks good, although it might be wise to add an "exists" function that returns false for df_conflict_entry and for NULL, to make the tests clearer, and to get a comment to point out the meaning of df_conflict_entry. Also, I think df_conflict_entry can be static bss in unpack-trees and not accessed through o->df_conflict_entry, since it's always the same value (being now universally initialized to a static pointer to heap...).

	-Daniel
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Daniel Barkalow <barkalow@iabervon.org> writes:

I am not sure about what you mean by "first bit", but I added this after noticing there was a case where the path was not picked up from index/head/remote correctly because the "pick up the path from ancestors, while we check for any_anc_missing and no_anc_exists condition" loop at the beginning already set it to point at stages[i]->name (which is an empty string "" name of the df-conflict entry).

But I notice that "aggressive" codepath is the only thing that wants to use the path (it uses it to check the working tree status), so maybe we should move that path computation business inside the aggressive codepath.

On Sat, 7 Apr 2007, Junio C Hamano wrote:

Your first bullet point. You must have added the check to the path line before you added the same check to the condition a few lines above, making this check no longer necessary.

                if (!stages[i] || stages[i] == o->df_conflict_entry)
                        any_anc_missing = 1;
                else {

If we get here, stages[i] != o->df_conflict_entry...

                        if (!path && stages[i] != o->df_conflict_entry)
                                path = stages[i]->name;
                        no_anc_exists = 0;
                }

So you don't need the second check if you've got the first one, and the first one makes more sense anyway; for the purposes of this entire section, we want df_conflict_entry to count as missing, and we don't look at the paths of missing entries regardless of whether they're specially marked.

	-Daniel
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