This is done to (1) ensure MERGE_HEAD is a ref, (2) obtain the oid without any prefixing by refs.c:repo_dwim_ref() Helped-by: Junio C Hamano <gitster@xxxxxxxxx> Signed-off-by: Michael Lohmann <mi.al.lohmann@xxxxxxxxx> --- Hi! On 12. Jan 2024, at 01:15, Junio C Hamano <gitster@xxxxxxxxx> wrote: > > This extends the functionality of `git log --merge` to also work with > > conflicts for rebase, cherry pick and revert. > > > > Signed-off-by: Michael Lohmann <mi.al.lohmann@xxxxxxxxx> > > --- > > ... It is basically the counterpart to > > `git show ${ACTION}_HEAD` for understanding the source of the conflict. > > I do not know about the validity of that approach to use *_HEAD, What I wanted to convey is that e.g. "git show CHERRY_PICK_HEAD" will tell you about the conflict from the perspective of the commit that is currently to be applied while "git log --merge" tells the story from the perspective of HEAD. So they are by no means the same, but can complement each other in getting an understanding about the conflict. > but we may want to tighten the original's use of repo_get > > - if (repo_get_oid(the_repository, "MERGE_HEAD", &oid)) > > - die("--merge without MERGE_HEAD?"); > > - other = lookup_commit_or_die(&oid, "MERGE_HEAD"); > > ... so that we won't be confused in a repository that has a tag > whose name happens to be MERGE_HEAD. We probably should be using > refs.c:refs_resolve_ref_unsafe() instead to _oid() here ... Here I am really at the limit of my understanding of the core functions. Is this roughly what you had in mind? From my testing it seems to do the job, but I don't understand the details "refs_resolve_ref_unsafe"... revision.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/revision.c b/revision.c index 2424c9bd67..786e1a3e89 100644 --- a/revision.c +++ b/revision.c @@ -1967,17 +1967,23 @@ static void prepare_show_merge(struct rev_info *revs) struct commit *head, *other; struct object_id oid; const char **prune = NULL; + const char *other_head; int i, prune_num = 1; /* counting terminating NULL */ struct index_state *istate = revs->repo->index; if (repo_get_oid(the_repository, "HEAD", &oid)) die("--merge without HEAD?"); head = lookup_commit_or_die(&oid, "HEAD"); - if (repo_get_oid(the_repository, "MERGE_HEAD", &oid)) + other_head = refs_resolve_ref_unsafe(get_main_ref_store(the_repository), + "MERGE_HEAD", + RESOLVE_REF_READING, + &oid, + NULL); + if (!other_head) die("--merge without MERGE_HEAD?"); - other = lookup_commit_or_die(&oid, "MERGE_HEAD"); + other = lookup_commit_or_die(&oid, other_head); add_pending_object(revs, &head->object, "HEAD"); - add_pending_object(revs, &other->object, "MERGE_HEAD"); + add_pending_object(revs, &other->object, other_head); bases = repo_get_merge_bases(the_repository, head, other); add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM); add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM); -- 2.43.0.284.g6c31128a96