sha1-file: introduce no-lazy-fetch has_object()

There have been a few bugs wherein Git fetches missing objects whenever
the existence of an object is checked, even though it does not need to
perform such a fetch. To resolve these bugs, we could look at all the
places that has_object_file() (or a similar function) is used. As a
first step, introduce a new function has_object() that checks for the
existence of an object, with a default behavior of not fetching if the
object is missing and the repository is a partial clone. As we verify
each has_object_file() (or similar) usage, we can replace it with
has_object(), and we will know that we are done when we can delete
has_object_file() (and the other similar functions).

Also, the new function has_object() has more appropriate defaults:
besides not fetching, it also does not recheck packed storage.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/sha1-file.c b/sha1-file.c
index 45fdb8415c..5866de0f65 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -1989,6 +1989,18 @@ int force_object_loose(const struct object_id *oid, time_t mtime)
 	return ret;
 }
 
+int has_object(struct repository *r, const struct object_id *oid,
+	       unsigned flags)
+{
+	int quick = !(flags & HAS_OBJECT_RECHECK_PACKED);
+	unsigned object_info_flags = OBJECT_INFO_SKIP_FETCH_OBJECT |
+		(quick ? OBJECT_INFO_QUICK : 0);
+
+	if (!startup_info->have_repository)
+		return 0;
+	return oid_object_info_extended(r, oid, NULL, object_info_flags) >= 0;
+}
+
 int repo_has_object_file_with_flags(struct repository *r,
 				    const struct object_id *oid, int flags)
 {