Re: [PATCH] git-repack doc: remove discussion of ancient caveat

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Fri, Jul 15 2022, Junio C Hamano wrote:

> Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
>
>> The backwards compatibility caveat discussed her hasn't been a concern
>> for anyone after Git v1.6.0. Let's simply remove it, I daresay
>> nobody's concerned these days with having git clients running older
>> than 2008-era git.
>
> For the purpose of this message, Git 1.6.0 has no significance.
> Anything newer than 1.4.4 should be able to understand packfiles
> that use delta-base-offset, even though they may not have used
> delta-base-offset when writing a new one.
>
> That's all academic.  I wouldn't have written the above if the
> proposed log message stopped here.  But with the rest of proposed
> log message that hints that the above statement is backed by a solid
> study of history, it is wrong to write a wrong version number there.
>
> I agree that it is safe to say that anything before Git 2.0.0 is
> irrelevant at this point (I would actually say before Git 2.16.0,
> i.e. anything older than 3-4 years).

1.4.4 is the version that introduced the flag, but the paragraphs I'm
removing is relevant to 1.6.0, as it discusses concerns with that
new-in-1.4.4 --delta-base-offset flag being turned on by default.

So this documentation matches e.g. the RelNotes update you made in
e903b4095a0 (Update draft release notes for 1.6.0, 2008-07-01).

I.e. 1.4.4 was released in late 2006, 1.6.0 in mid-2008. Hence the
mention of "git clients older than 2008-era git" not being a concern.

I.e. the target audience for this bit of documentatino is someone
running 1.6.0. or newer that's also concerned about pre-1.4.4.

>> See b6945f570ac (git-repack: repo.usedeltabaseoffset, 2006-10-13) and
>> 9f17688d93c (update git-repack documentation wrt
>> repack.UseDeltaBaseOffset, 2010-02-04) for the commits that previously
>> introduced and adjusted this documentation.
>>
>> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>> ---
>>  Documentation/git-repack.txt | 10 ----------
>>  1 file changed, 10 deletions(-)
>>
>> diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
>> index 0bf13893d81..fe1eac37090 100644
>> --- a/Documentation/git-repack.txt
>> +++ b/Documentation/git-repack.txt
>> @@ -218,16 +218,6 @@ CONFIGURATION
>>  Various configuration variables affect packing, see
>>  linkgit:git-config[1] (search for "pack" and "delta").
>>  
>> -By default, the command passes `--delta-base-offset` option to
>> -'git pack-objects'; this typically results in slightly smaller packs,
>> -but the generated packs are incompatible with versions of Git older than
>> -version 1.4.4. If you need to share your repository with such ancient Git
>> -versions, either directly or via the dumb http protocol, then you
>> -need to set the configuration variable `repack.UseDeltaBaseOffset` to
>> -"false" and repack. Access from old Git versions over the native protocol
>> -is unaffected by this option as the conversion is performed on the fly
>> -as needed in that case.
>> -
>>  Delta compression is not used on objects larger than the
>>  `core.bigFileThreshold` configuration variable and on files with the
>>  attribute `delta` set to false.