From: Junio C Hamano <gitster@pobox.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: git@vger.kernel.org, peff@peff.net
Subject: Re: [PATCH v2] doc: remove misleading documentation on pack names
Date: Wed, 22 Jul 2020 14:09:37 -0700 [thread overview]
Message-ID: <xmqq5zaf5ka6.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200722202629.109277-1-johannes@sipsolutions.net> (Johannes Berg's message of "Wed, 22 Jul 2020 22:26:29 +0200")
Johannes Berg <johannes@sipsolutions.net> writes:
> The index-pack documentation explicitly states that the pack
> name is derived from the sorted list of object names, but
> that clearly isn't true. I can't seem to be able to figure
> out if this was ever changed though.
>
> Be less explicit in the docs as to what the exact output is,
> and just say that it's whatever goes into the pack name.
>
> Really it seems to be the sha1 of the entire file, without
> the checksum footer.
Please avoid "seems to be" and spend a bit of effort digging the
history especially when we are not in a hurry to get to the definite
answer. We can go "less explicit", or be a bit more informative by
saying that it is the trailer hash that is standard practice shared
across our binary files like the index and the packfile.
I think this is 1190a1ac (pack-objects: name pack files after
trailer hash, 2013-12-05). It forgot to update the comment before
write_idx_file() function when it did this change:
/*
* On entry *sha1 contains the pack content SHA1 hash, on exit it is
* the SHA1 hash of sorted object names. The objects array passed in
* will be sorted by SHA1 on exit.
*/
const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects,
int nr_objects, const struct pack_idx_option *opts,
- unsigned char *sha1)
+ const unsigned char *sha1)
{
Obviously, after it turned *sha1 into 'const', it no longer is
possible for it to have anything different from what was passed in
upon exit.
> +Once the index has been created, the hash that goes into the name of
> +the pack/idx file is printed to stdout. If --stdin was also used then
> +this is prefixed by either "pack\t", or "keep\t" if a new .keep file
> +was successfully created. This is useful to remove a .keep file used
> +as a lock to prevent the race with 'git repack' mentioned above.
The change is good---I made sure that among these filve lines, what
changed was only the first one and half lines. I however would have
preferred not to see the line rewrapping.
Thanks.
next prev parent reply other threads:[~2020-07-22 21:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 20:26 [PATCH v2] doc: remove misleading documentation on pack names Johannes Berg
2020-07-22 21:09 ` Junio C Hamano [this message]
2020-07-22 21:14 ` Johannes Berg
2020-07-22 21:16 ` Junio C Hamano
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