On Wed, Aug 4, 2010 at 10:57 PM, Christian Couder
<chriscool@tuxfamily.org> wrote:
> On Wednesday 04 August 2010 14:42:50 Nguyen Thai Ngoc Duy wrote:
>> On Wed, Aug 4, 2010 at 9:58 PM, Christian Couder
>>
>> <chriscool@tuxfamily.org> wrote:
>> >> > I will
>> >> > try to have a deeper look at that, but it would help if you could give
>> >> > an example of a command that triggers this behavior.
>> >>
>> >> The following patch add "sha1" command. These commands give different
>> >> sha1:
>> >>
>> >> git sha1 `git rev-parse HEAD` `git rev-parse HEAD^` A
>> >> git sha1 `git rev-parse HEAD` `git rev-parse HEAD^` B
>> >
>> > Yes, but that does not mean that the content of the object returned by
>> > lookup_commit(A) is not the content of A.
>> >
>> > Or do you have an example where the content of the object returned by
>> > lookup_commit(A) is not the content of A?
>>
>> Both return the content of B. I modified my patch a bit to also show
>> the content, ((struct commit*)obj)->buffer.
>
> I also modified your patch but I don't get any content shown when using
> lookup_commit()
>
> I use:
>
> diff --git a/builtin/sha1.c b/builtin/sha1.c
> new file mode 100644
> index 0000000..8e081b2
> --- /dev/null
> +++ b/builtin/sha1.c
> @@ -0,0 +1,27 @@
> +#include "cache.h"
> +#include "commit.h"
> +
> +int cmd_sha1(int argc, char **argv)
> +{
> +       unsigned char old[20];
> +       unsigned char new[20];
> +       struct object *obj;
> +
> +       get_sha1_hex(argv[1], old);
> +       get_sha1_hex(argv[2], new);
> +       printf("old  = %s\nnew  = %s\n", argv[1], argv[2]);
> +       replace_pair(old, new);
> +       if (argv[3][0] == 'A')
> +              obj = parse_object(old);
> +       else {
> +              struct commit *com = lookup_commit(old);
> +              if (com->buffer)
> +                      printf("commit buffer:\n%s", com->buffer);
> +              else
> +                      printf("no commit buffer\n");
> +              obj = (struct object *)com;
> +       }
> +
> +       printf("sha1 = %s\n", sha1_to_hex(obj->sha1));
> +       return 0;
> +}
>
> and I get:
>
> $ git sha1 `git rev-parse HEAD` `git rev-parse HEAD^` B
> old  = 5b4585a035e2ba61573273dacc6d17d7e8fcbc7d
> new  = c9b402bd93105f80f3c5d67ecfccc8ba36810613
> no commit buffer
> sha1 = 5b4585a035e2ba61573273dacc6d17d7e8fcbc7d
>
> Could you show what code you use?

You need parse_commit() (unless somebody already did that before
lookup_commit()).
-- 
Duy