Files
git-mirror/merge-ort-wrappers.c
Elijah Newren 4e5d9de96c merge-ort: add new merge_ort_generic() function
merge-recursive.[ch] have three entry points:
  * merge_trees()
  * merge_recursive()
  * merge_recursive_generic()
merge-ort*.[ch] only has equivalents for the first two.  Add an
equivalent for the final entry point, so we can switch callers to
use it and remove merge-recursive.[ch].

While porting it over, finally fix the issue with the label for the
ancestor (used when merge.conflictStyle=diff3 as a conflict label).
merge-recursive.c has traditionally not allowed callers to set that
label, but I have found that problematic for years.

(Side note: This function was initially part of the merge-ort rewrite,
but reviewers questioned the ancestor label funnyness which I was
never really happy with anyway.  It resulted in me jettisoning it and
hoping at the time that I would eventually be able to force the existing
callers to use some other API.  That worked with `git stash`, as per
874cf2a604 (stash: apply stash using 'merge_ort_nonrecursive()',
2022-05-10), but this API is the most reasonable one for `git am` and
`git merge-recursive`, if we can just allow them some freedom over the
ancestor label.)

The merge_recursive_generic() function did not know whether it was being
invoked by `git stash`, `git merge-recursive`, or `git am`, and the
choice of meaningful ancestor label, when there is a unique ancestor,
varies for these different callers:

  * git am: ancestor is a constructed "fake ancestor" that user knows
            nothing about and has no access to.  (And is different than
            the normal thing we mean by a "virtual merge base" which is
            the merging of merge bases.)
  * git merge-recursive: ancestor might be a tree, but at least it
                         was one specified by the user (if they invoked
                         merge-recursive directly)
  * git stash: ancestor was the commit serving as the stash base

Thus, using a label like "constructed merge base" (as
merge_recursive_generic() does) presupposes that `git am` is the only
caller; it is incorrect for other callers.  This label has thrown me off
more than once.  Allow the caller to override when there is a unique
merge base.

Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-18 09:48:30 -07:00

131 lines
3.2 KiB
C

#include "git-compat-util.h"
#include "gettext.h"
#include "hash.h"
#include "hex.h"
#include "lockfile.h"
#include "merge-ort.h"
#include "merge-ort-wrappers.h"
#include "read-cache-ll.h"
#include "repository.h"
#include "tag.h"
#include "tree.h"
#include "commit.h"
static int unclean(struct merge_options *opt, struct tree *head)
{
/* Sanity check on repo state; index must match head */
struct strbuf sb = STRBUF_INIT;
if (head && repo_index_has_changes(opt->repo, head, &sb)) {
error(_("Your local changes to the following files would be overwritten by merge:\n %s"),
sb.buf);
strbuf_release(&sb);
return -1;
}
return 0;
}
int merge_ort_nonrecursive(struct merge_options *opt,
struct tree *head,
struct tree *merge,
struct tree *merge_base)
{
struct merge_result result;
if (unclean(opt, head))
return -1;
if (oideq(&merge_base->object.oid, &merge->object.oid)) {
printf_ln(_("Already up to date."));
return 1;
}
memset(&result, 0, sizeof(result));
merge_incore_nonrecursive(opt, merge_base, head, merge, &result);
merge_switch_to_result(opt, head, &result, 1, 1);
return result.clean;
}
int merge_ort_recursive(struct merge_options *opt,
struct commit *side1,
struct commit *side2,
const struct commit_list *merge_bases,
struct commit **result)
{
struct tree *head = repo_get_commit_tree(opt->repo, side1);
struct merge_result tmp;
if (unclean(opt, head))
return -1;
memset(&tmp, 0, sizeof(tmp));
merge_incore_recursive(opt, merge_bases, side1, side2, &tmp);
merge_switch_to_result(opt, head, &tmp, 1, 1);
*result = NULL;
return tmp.clean;
}
static struct commit *get_ref(struct repository *repo,
const struct object_id *oid,
const char *name)
{
struct object *object;
object = deref_tag(repo, parse_object(repo, oid),
name, strlen(name));
if (!object)
return NULL;
if (object->type == OBJ_TREE)
return make_virtual_commit(repo, (struct tree*)object, name);
if (object->type != OBJ_COMMIT)
return NULL;
if (repo_parse_commit(repo, (struct commit *)object))
return NULL;
return (struct commit *)object;
}
int merge_ort_generic(struct merge_options *opt,
const struct object_id *head,
const struct object_id *merge,
int num_merge_bases,
const struct object_id *merge_bases,
struct commit **result)
{
int clean;
struct lock_file lock = LOCK_INIT;
struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
struct commit_list *ca = NULL;
if (merge_bases) {
int i;
for (i = 0; i < num_merge_bases; ++i) {
struct commit *base;
if (!(base = get_ref(opt->repo, &merge_bases[i],
oid_to_hex(&merge_bases[i]))))
return error(_("Could not parse object '%s'"),
oid_to_hex(&merge_bases[i]));
commit_list_insert(base, &ca);
}
}
repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
clean = merge_ort_recursive(opt, head_commit, next_commit, ca,
result);
free_commit_list(ca);
if (clean < 0) {
rollback_lock_file(&lock);
return clean;
}
if (write_locked_index(opt->repo->index, &lock,
COMMIT_LOCK | SKIP_IF_UNCHANGED))
return error(_("Unable to write index."));
return clean ? 0 : 1;
}