[PATCH v2 0/8] object.c: add and use "is expected" utility function + object_as_type() use

This relatively simple series builds on [1] and [2] to intorduce a utility function for the "expected type X, got Y" error messages. See [3] for the v1 of this series.

There was an embarrassing error in v1 where I left in some WIP assertion code, and we'd print a nonsensical error message in the lookup_commit_reference_gently() codepath.

That's now fixed gone, and there's a new test to assert the exact output we get from a failure in lookup_commit_reference_gently(). Aside from not reading my own patches carefully enough before submission, I didn't catch that case because nothing tested for the output.

1. https://lore.kernel.org/git/cover-00.10-0000000000-20210420T124428Z-avarab@gmail.com/
2. https://lore.kernel.org/git/cover-00.10-0000000000-20210420T125415Z-avarab@gmail.com/
3. https://lore.kernel.org/git/cover-0.7-0000000000-20210409T083436Z-avarab@gmail.com/

Ævar Arnfjörð Bjarmason (8):
  tree.c: fix misindentation in parse_tree_gently()
  object.c: add a utility function for "expected type X, got Y"
  object.c: add and use oid_is_type_or_die_msg() function
  commit-graph: use obj->type, not object_as_type()
  branch tests: assert lookup_commit_reference_gently() error
  commit.c: don't use deref_tag() -> object_as_type()
  object.c: normalize brace style in object_as_type()
  object.c: remove "quiet" parameter from object_as_type()

 blob.c                     |  2 +-
 builtin/commit-graph.c     |  2 +-
 builtin/fsck.c             |  2 +-
 builtin/index-pack.c       |  9 +++----
 combine-diff.c             |  3 +--
 commit.c                   | 29 ++++++++++++++--------
 merge-recursive.c          |  5 +++-
 object.c                   | 51 +++++++++++++++++++++++++++++++-------
 object.h                   | 10 +++++++-
 refs.c                     |  2 +-
 t/helper/test-reach.c      |  2 +-
 t/t3201-branch-contains.sh |  8 +++++-
 tag.c                      |  2 +-
 tree.c                     | 15 +++++------
 14 files changed, 98 insertions(+), 44 deletions(-)

Range-diff against v1:
1:  4bf9a4f7a1 = 1:  c39b235035 tree.c: fix misindentation in parse_tree_gently()
2:  0be843e838 = 2:  1b472fcd85 object.c: add a utility function for "expected type X, got Y"
3:  fb2e4feb3d = 3:  22e7d9a3db object.c: add and use oid_is_type_or_die_msg() function
4:  995135c814 = 4:  8e43d44911 commit-graph: use obj->type, not object_as_type()
-:  ---------- > 5:  8982c42127 branch tests: assert lookup_commit_reference_gently() error
5:  754d5ae267 ! 6:  f337a5442d commit.c: don't use deref_tag() -> object_as_type()
    @@ Commit message
         of OBJ_{COMMIT,TREE,BLOB,TAG} here, not the bare-bones initialization
         object_as_type() might be called on to do.
     
    +    Even though we can read deref_tag() and see that it won't return
    +    OBJ_NONE and friends, let's add a BUG() assertion here to help future
    +    maintenance.
    +
         Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
      ## commit.c ##
    @@ commit.c: const char *commit_type = "commit";
      		return NULL;
     -	return object_as_type(obj, OBJ_COMMIT, quiet);
     +
    ++	if (obj->type <= 0)
    ++		BUG("should have initialized obj->type = OBJ_{COMMIT,TREE,BLOB,TAG} from deref_tag()");
     +	if (obj->type != OBJ_COMMIT) {
    -+		enum object_type want = OBJ_COMMIT;
    -+		if (!quiet)
    -+			oid_is_type_or_error(oid, OBJ_COMMIT, &want);
    ++		if (!quiet) {
    ++			enum object_type have = obj->type;
    ++			oid_is_type_or_error(oid, OBJ_COMMIT, &have);
    ++		}
     +		return NULL;
     +	}
     +	return (struct commit *)obj;
6:  e414cfe40c = 7:  893b178573 object.c: normalize brace style in object_as_type()
7:  64360ac260 ! 8:  a47d23f1b1 object.c: remove "quiet" parameter from object_as_type()
    @@ blob.c
     @@ blob.c: struct blob *lookup_blob(struct repository *r, const struct object_id *oid)
      	struct object *obj = lookup_object(r, oid);
      	if (!obj)
    - 		return create_object(r, oid, alloc_blob_node(r));
    + 		return create_blob(r, oid);
     -	return object_as_type(obj, OBJ_BLOB, 0);
     +	return object_as_type(obj, OBJ_BLOB);
      }
    - 
    - int parse_blob_buffer(struct blob *item)
     
      ## builtin/fsck.c ##
     @@ builtin/fsck.c: static void mark_unreachable_referents(const struct object_id *oid)
    @@ builtin/fsck.c: static void mark_unreachable_referents(const struct object_id *o
      	options.walk = mark_used;
     
      ## commit.c ##
    -@@ commit.c: struct commit *lookup_commit_reference_gently(struct repository *r,
    - 		return NULL;
    - 
    - 	if (obj->type != OBJ_COMMIT) {
    --		enum object_type want = OBJ_COMMIT;
    -+		if (obj->type <= 0)
    -+			BUG("noes");
    - 		if (!quiet)
    --			oid_is_type_or_error(oid, OBJ_COMMIT, &want);
    -+			fprintf(stderr, "noes ohes");/*
    -+			oid_is_type_or_error(oid, OBJ_COMMIT, &obj->type);*/
    - 		return NULL;
    - 	}
    - 	return (struct commit *)obj;
     @@ commit.c: struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
      	struct object *obj = lookup_object(r, oid);
      	if (!obj)
    - 		return create_object(r, oid, alloc_commit_node(r));
    + 		return create_commit(r, oid);
     -	return object_as_type(obj, OBJ_COMMIT, 0);
     +	return object_as_type(obj, OBJ_COMMIT);
      }
    @@ tag.c
     @@ tag.c: struct tag *lookup_tag(struct repository *r, const struct object_id *oid)
      	struct object *obj = lookup_object(r, oid);
      	if (!obj)
    - 		return create_object(r, oid, alloc_tag_node(r));
    + 		return create_tag(r, oid);
     -	return object_as_type(obj, OBJ_TAG, 0);
     +	return object_as_type(obj, OBJ_TAG);
      }
    @@ tree.c
     @@ tree.c: struct tree *lookup_tree(struct repository *r, const struct object_id *oid)
      	struct object *obj = lookup_object(r, oid);
      	if (!obj)
    - 		return create_object(r, oid, alloc_tree_node(r));
    + 		return create_tree(r, oid);
     -	return object_as_type(obj, OBJ_TREE, 0);
     +	return object_as_type(obj, OBJ_TREE);
      }