Convert lookup_commit* to struct object_id

Convert lookup_commit, lookup_commit_or_die,
lookup_commit_reference, and lookup_commit_reference_gently to take
struct object_id arguments.

Introduce a temporary in parse_object buffer in order to convert this
function.  This is required since in order to convert parse_object and
parse_object_buffer, lookup_commit_reference_gently and
lookup_commit_or_die would need to be converted.  Not introducing a
temporary would therefore require that lookup_commit_or_die take a
struct object_id *, but lookup_commit would take unsigned char *,
leaving a confusing and hard-to-use interface.

parse_object_buffer will lose this temporary in a later patch.

This commit was created with manual changes to commit.c, commit.h, and
object.c, plus the following semantic patch:

@@
expression E1, E2;
@@
- lookup_commit_reference_gently(E1.hash, E2)
+ lookup_commit_reference_gently(&E1, E2)

@@
expression E1, E2;
@@
- lookup_commit_reference_gently(E1->hash, E2)
+ lookup_commit_reference_gently(E1, E2)

@@
expression E1;
@@
- lookup_commit_reference(E1.hash)
+ lookup_commit_reference(&E1)

@@
expression E1;
@@
- lookup_commit_reference(E1->hash)
+ lookup_commit_reference(E1)

@@
expression E1;
@@
- lookup_commit(E1.hash)
+ lookup_commit(&E1)

@@
expression E1;
@@
- lookup_commit(E1->hash)
+ lookup_commit(E1)

@@
expression E1, E2;
@@
- lookup_commit_or_die(E1.hash, E2)
+ lookup_commit_or_die(&E1, E2)

@@
expression E1, E2;
@@
- lookup_commit_or_die(E1->hash, E2)
+ lookup_commit_or_die(E1, E2)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 6faa3c0d24..91dd753dd9 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -566,7 +566,7 @@ static void find_merge_parents(struct merge_parents *result,
 		commit_list_insert(parent, &parents);
 		add_merge_parent(result, &obj->oid, &parent->object.oid);
 	}
-	head_commit = lookup_commit(head->hash);
+	head_commit = lookup_commit(head);
 	if (head_commit)
 		commit_list_insert(head_commit, &parents);
 	parents = reduce_heads(parents);
@@ -633,7 +633,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		struct commit *head;
 		struct rev_info rev;
 
-		head = lookup_commit_or_die(head_oid.hash, "HEAD");
+		head = lookup_commit_or_die(&head_oid, "HEAD");
 		init_revisions(&rev, NULL);
 		rev.commit_format = CMIT_FMT_ONELINE;
 		rev.ignore_merges = 1;