Re: [PATCH 0/2] finding the fork point from reflog entries

[Junio C Hamano <gitster@pobox.com>]

John Keeping <john@keeping.me.uk> writes:

> To clarify: the particular commit in the calls above happens to be the
> oldest entry in the reflog, if I pick a newer entry then it works.
>
> It seems that for_each_reflog_ent isn't returning the oldest entry;
> revs.nr is 62 whereas "git rev-list -g origin/master | wc -l" gives 63.

Perhaps this on top.

One thing I somehow feel dirty about this change is that we have to
include diff.h only to include revision.h only to get the definition
of TMP_MARK. Perhaps object.h should be the header that defines the
bit assignment for objects.flags bit-field.

 builtin/merge-base.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/builtin/merge-base.c b/builtin/merge-base.c
index 7b9bc15..7fdc3de 100644
--- a/builtin/merge-base.c
+++ b/builtin/merge-base.c
@@ -2,6 +2,8 @@
 #include "cache.h"
 #include "commit.h"
 #include "refs.h"
+#include "diff.h"
+#include "revision.h"
 #include "parse-options.h"
 
 static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
@@ -91,18 +93,32 @@ struct rev_collect {
 	struct commit **commit;
 	int nr;
 	int alloc;
+	unsigned int initial : 1;
 };
 
+static void add_one_commit(unsigned char *sha1, struct rev_collect *revs)
+{
+	struct commit *commit = lookup_commit(sha1);
+
+	if (!commit || (commit->object.flags & TMP_MARK))
+		return;
+
+	ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
+	revs->commit[revs->nr++] = commit;
+	commit->object.flags |= TMP_MARK;
+}
+
 static int collect_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 				  const char *ident, unsigned long timestamp,
 				  int tz, const char *message, void *cbdata_)
 {
 	struct rev_collect *revs = cbdata_;
-	struct commit *commit = lookup_commit(nsha1);
-	if (commit) {
-		ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
-		revs->commit[revs->nr++] = commit;
+
+	if (revs->initial) {
+		add_one_commit(osha1, revs);
+		revs->initial = 0;
 	}
+	add_one_commit(nsha1, revs);
 	return 0;
 }
 
@@ -131,8 +147,12 @@ static int handle_reflog(int argc, const char **argv)
 
 	derived = lookup_commit_reference(sha1);
 	memset(&revs, 0, sizeof(revs));
+	revs.initial = 1;
 	for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
 
+	for (i = 0; i < revs.nr; i++)
+		revs.commit[i]->object.flags &= ~TMP_MARK;
+
 	bases = get_merge_bases_many(derived, revs.nr, revs.commit, 0);
 
 	/*