sha1-file: remove OBJECT_INFO_SKIP_CACHED

In a partial clone, if a user provides the hash of the empty tree ("git
mktree </dev/null" - for SHA-1, this is 4b825d...) to a command which
requires that that object be parsed, for example:

  git diff-tree 4b825d <a non-empty tree>

then Git will lazily fetch the empty tree, unnecessarily, because
parsing of that object invokes repo_has_object_file(), which does not
special-case the empty tree.

Instead, teach repo_has_object_file() to consult find_cached_object()
(which handles the empty tree), thus bringing it in line with the rest
of the object-store-accessing functions. A cost is that
repo_has_object_file() will now need to oideq upon each invocation, but
that is trivial compared to the filesystem lookup or the pack index
search required anyway. (And if find_cached_object() needs to do more
because of previous invocations to pretend_object_file(), all the more
reason to be consistent in whether we present cached objects.)

As a historical note, the function now known as repo_read_object_file()
was taught the empty tree in 346245a1bb ("hard-code the empty tree
object", 2008-02-13), and the function now known as oid_object_info()
was taught the empty tree in c4d9986f5f ("sha1_object_info: examine
cached_object store too", 2011-02-07). repo_has_object_file() was never
updated, perhaps due to oversight. The flag OBJECT_INFO_SKIP_CACHED,
introduced later in dfdd4afcf9 ("sha1_file: teach
sha1_object_info_extended more flags", 2017-06-26) and used in
e83e71c5e1 ("sha1_file: refactor has_sha1_file_with_flags", 2017-06-26),
was introduced to preserve this difference in empty-tree handling, but
now it can be removed.

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

diff --git a/object-store.h b/object-store.h
index 7f7b3cdd806b756eefb86c7d116ba9a9a6c62558..073d64d5b83a25de67387d82354afa3f1d5dbaca 100644 (file)
--- a/object-store.h
+++ b/object-store.h
@@ -271,8 +271,6 @@ struct object_info {
 #define OBJECT_INFO_LOOKUP_REPLACE 1
 /* Allow reading from a loose object file of unknown/bogus type */
 #define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
-/* Do not check cached storage */
-#define OBJECT_INFO_SKIP_CACHED 4
 /* Do not retry packed storage after checking packed and loose storage */
 #define OBJECT_INFO_QUICK 8
 /* Do not check loose object */

diff --git a/sha1-file.c b/sha1-file.c
index 188de57634bb1b0b15fbe3ab97f062bed7927763..03ae9ae93a53d911137a8f06aa687472c73806c9 100644 (file)
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -1417,6 +1417,7 @@ int oid_object_info_extended(struct repository *r, const struct object_id *oid,
                             struct object_info *oi, unsigned flags)
 {
        static struct object_info blank_oi = OBJECT_INFO_INIT;
+       struct cached_object *co;
        struct pack_entry e;
        int rtype;
        const struct object_id *real = oid;
@@ -1431,24 +1432,22 @@ int oid_object_info_extended(struct repository *r, const struct object_id *oid,
        if (!oi)
                oi = &blank_oi;
 
-       if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
-               struct cached_object *co = find_cached_object(real);
-               if (co) {
-                       if (oi->typep)
-                               *(oi->typep) = co->type;
-                       if (oi->sizep)
-                               *(oi->sizep) = co->size;
-                       if (oi->disk_sizep)
-                               *(oi->disk_sizep) = 0;
-                       if (oi->delta_base_sha1)
-                               hashclr(oi->delta_base_sha1);
-                       if (oi->type_name)
-                               strbuf_addstr(oi->type_name, type_name(co->type));
-                       if (oi->contentp)
-                               *oi->contentp = xmemdupz(co->buf, co->size);
-                       oi->whence = OI_CACHED;
-                       return 0;
-               }
+       co = find_cached_object(real);
+       if (co) {
+               if (oi->typep)
+                       *(oi->typep) = co->type;
+               if (oi->sizep)
+                       *(oi->sizep) = co->size;
+               if (oi->disk_sizep)
+                       *(oi->disk_sizep) = 0;
+               if (oi->delta_base_sha1)
+                       hashclr(oi->delta_base_sha1);
+               if (oi->type_name)
+                       strbuf_addstr(oi->type_name, type_name(co->type));
+               if (oi->contentp)
+                       *oi->contentp = xmemdupz(co->buf, co->size);
+               oi->whence = OI_CACHED;
+               return 0;
        }
 
        while (1) {
@@ -1932,8 +1931,7 @@ int repo_has_object_file_with_flags(struct repository *r,
 {
        if (!startup_info->have_repository)
                return 0;
-       return oid_object_info_extended(r, oid, NULL,
-                                       flags | OBJECT_INFO_SKIP_CACHED) >= 0;
+       return oid_object_info_extended(r, oid, NULL, flags) >= 0;
 }
 
 int repo_has_object_file(struct repository *r,