Sven Brauch <> writes:

> From 2e7b5aed771faeff654a447346bb0b57570d9569 Mon Sep 17 00:00:00 2001
> From: Sven Brauch <>
> Date: Tue, 5 Nov 2013 20:06:21 +0100
> Subject: [PATCH] git-cat-file: fix output when format string contains no
>  variables

Thanks; first some procedural issues:

 - Omit the first line "From 2e7b..."; that does not belong to any
   patch submission (it is a separator used between messages in the
   mailbox formatted file "format-patch --stdout" produces).

 - The second line "From: Sven..." records exactly the same address
   as the e-mail you are sending out, so it should be omitted as

 - The third line "Date: ..." is not the time we the general public
   sees your fix for the first time, which is what "Date: " of your
   e-mail header already records, so we do not need it either.

 - And the last one "Subject: ..." is redundant; we can see it in
   your e-mail header.

In general, the latter three lines are produced by format-patch to
help you fill header fields in the MUA of your choice by cutting
(not copying) and pasting. Unless there is a valid reason to have
values different from what recipients would see in the e-mail header
(and there often isn't, unless you are forwarding somebody else's
patch, in which case you may want to use "From: ", or you are
responding to an ongoing discussion with a patch, in which case you
may want to use "Subject: "), please remove them after copying them
out to your e-mail header.

> When the format string for git-cat-object --batch-check contained no
> variables, the function would not actually look for the object on disk,
> but just verify that the hash is correct. Thus it would report no error
> if asking for objects which did not actually exist on disk if the SHA hash
> looked ok.
> Example of buggy behaviour:
> echo "XYZ" | git hash-object --stdin | git cat-file --batch-check="found"
> would report "found" although the manpage claims it would report an error.

An excellent log message.  It would have been even better to add a
new test to t1006 based on this reproduction recipe.

> Signed-off-by: Sven Brauch <>
> ---
> Notes:
>     This fixes a bug where git-cat-file --batch-check would erroneously tell
>     that objects exist while they did in fact not in case the argument to
>     --batch-check was just a constant strig (i.e. no %(...) variables).
>     The reason was that calling sha1_object_info_extended while requesting no
>     properties of the object would not even verify this object existed, or 
> more
>     exactly, sha1_loose_object_info would not do that.
>     I'm entirely unfamiliar with the git codebase; the suggested fix ensures
>     that always at least one property is requested. If there's a better way
>     to fix this issue, please let me know.

I think the real problem is that sha1_loose_object_info() is called
by sha1_object_info_extended(), when it does not find a cached or a
packed object, and the callee assumes that it is asked to fill in
only the requested pieces of information while the caller does not
even bother to check if such an object actually exists.

How about doing it like the attached instead?

-- >8 --
Subject: sha1_loose_object_info(): do not return success on missing object

Since 052fe5ea (sha1_loose_object_info: make type lookup optional,
2013-07-12), sha1_loose_object_info() returns happily without
checking if the object in question exists, which is not what the the
caller sha1_object_info_extended() expects; the caller does not even
bother checking the existence of the object itself.

Noticed-by: Sven Brauch <>
Signed-off-by: Junio C Hamano <>

  Oh, by the way, there is this one iffy bit in batch_one_object():

          if (get_sha1(obj_name, data->sha1)) {
                  printf("%s missing\n", obj_name);
                  return 0;

  At this point, the object _may_ be missing, but the obj_name may be
  malformed, so saying "missing" is not strictly correct.  If, for
  example, you misspelled the name of the master branch, you would get

          $ echo mastre | git cat-file --batch-check=foo
          mastre missing

  I however doubt that it is a good idea to reword this message by
  adding a logic to tell misspelled object name and missing object
  name apart.  The users of "cat-file --batch-check" are not
  expecting to be able to distinguish these two classes of errors

 sha1_file.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 7dadd04..00220a4 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2486,12 +2486,11 @@ static int sha1_loose_object_info(const unsigned char 
         * need to look inside the object at all.
        if (!oi->typep && !oi->sizep) {
-               if (oi->disk_sizep) {
-                       struct stat st;
-                       if (stat_sha1_file(sha1, &st) < 0)
-                               return -1;
+               struct stat st;
+               if (stat_sha1_file(sha1, &st) < 0)
+                       return -1;
+               if (oi->disk_sizep)
                        *oi->disk_sizep = st.st_size;
-               }
                return 0;
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