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From: Stefan Beller <sbeller@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: git <git@vger.kernel.org>, Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes
Date: Wed, 3 Jan 2018 13:16:20 -0800	[thread overview]
Message-ID: <CAGZ79kbC5tsL8R-tUBxHoZzxYiqiWwYS61F7cLfTZeb0Wu1LGA@mail.gmail.com> (raw)
In-Reply-To: <xmqqo9mahdll.fsf@gitster.mtv.corp.google.com>

On Wed, Jan 3, 2018 at 12:49 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Stefan Beller <sbeller@google.com> writes:
>
>> Thanks Junio for review of this series!
>> The only change in this version of the series is
>>
>> --- a/unpack-trees.c
>> +++ b/unpack-trees.c
>> @@ -2140,7 +2140,7 @@ int oneway_merge(const struct cache_entry * const *src,
>>                                 update |= CE_UPDATE;
>>                 }
>>                 if (S_ISGITLINK(old->ce_mode) && should_update_submodules() &&
>> -                   !verify_uptodate(old, o))
>> +                   o->update && !verify_uptodate(old, o))
>>                         update |= CE_UPDATE;
>>                 add_entry(o, old, update, 0);
>>
>
> Sounds OK.
>
> I wonder why o->update is not at the very beginning of the &&-chain,
> though.  After all, the one above this addition begins with o->reset
> && o->update *not* because of the performance concern, but primarily
> due to logic flow.  I.e. "if we are resetting and updating the
> working tree, then..." comes first before saying "we may need to
> flip CE_UPDATE bit in update variable if the file in the working
> tree is not up to date and it is within a narrow checkout area".

It shows that I work too much with submodules. ;)
"If we have a submodule and ..." seemed to be the important
part when writing the patch.

> Of course, because verify_uptodate() is rather expensive, checking
> o->update before that makes sense from micro-optimization's point of
> view, too.

I would think S_ISGITLINK, should_update_submodules as well
as o->update are all on the same order of magnitude of costs
(some couple number of operations)  when
compared to verify_uptodate (spawning processes),
so as long as verify_uptodate goes last we'd be fine.

>
> So after thinking aloud like the above, I am reasonably sure that
> you want to check o->update as the very first thing in this new if
> statement.

Thanks for double checking and thinking about the code base with
a less submodule centric point of view.

Mind to squash it locally or want me to resend?
For a resend I'll wait a couple of days to see if there are more
comments needing to be addressed.


>
>> v2:
>> I dropped the patch to `same()` as I realized we only need to fix the
>> oneway_merge function, the others (two, three way merge) are fine as
>> they have the checks already in place.
>
> This is a bit flawed argument, no?  Checking working tree paths
> unconditionally in same(), which does not even know if we are
> touching the working tree paths, is broken.  Unless "they have the
> checks already in place" refers to checks that bypasses calls to
> same() when we are not touching working tree paths, that is, but
> obviously that is not what is going on.
>
> Will queue.  Thanks for working on this.
>
>

  reply	other threads:[~2018-01-03 21:16 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-19 22:26 [PATCH 0/5] Fix --recurse-submodules for submodule worktree changes Stefan Beller
2017-12-19 22:26 ` [PATCH 1/5] t/lib-submodule-update.sh: clarify test Stefan Beller
2017-12-19 22:26 ` [PATCH 2/5] t/lib-submodule-update.sh: Fix test ignoring ignored files in submodules Stefan Beller
2017-12-22 19:34   ` Junio C Hamano
2017-12-27 19:27     ` Stefan Beller
2017-12-19 22:26 ` [PATCH 3/5] t/lib-submodule-update.sh: add new test for submodule internal change Stefan Beller
2017-12-19 22:31   ` Jonathan Nieder
2017-12-19 22:35     ` Stefan Beller
2017-12-19 22:26 ` [PATCH 4/5] unpack-trees: Fix same() for submodules Stefan Beller
2017-12-19 22:26 ` [PATCH 5/5] submodule: submodule_move_head omits old argument in forced case Stefan Beller
2017-12-19 22:44   ` Jonathan Nieder
2017-12-19 22:54     ` Stefan Beller
2017-12-19 23:15       ` Jonathan Nieder
2017-12-20  0:01       ` Jonathan Nieder
2017-12-20 19:36         ` Stefan Beller
2017-12-20 19:38           ` Stefan Beller
2017-12-27 22:57 ` [PATCHv2 0/5] Fix --recurse-submodules for submodule worktree changes Stefan Beller
2017-12-27 22:57   ` [PATCHv2 1/5] t/helper/test-lazy-name-hash: fix compilation Stefan Beller
2017-12-27 22:57   ` [PATCHv2 2/5] t/lib-submodule-update.sh: clarify test Stefan Beller
2017-12-27 22:57   ` [PATCHv2 3/5] t/lib-submodule-update.sh: Fix test ignoring ignored files in submodules Stefan Beller
2017-12-27 22:57   ` [PATCHv2 4/5] unpack-trees: oneway_merge to update submodules Stefan Beller
2018-01-02 19:43     ` Junio C Hamano
2018-01-02 23:04       ` Stefan Beller
2018-01-03  1:12       ` [PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes Stefan Beller
2018-01-03  1:12         ` [PATCH 1/5] t/helper/test-lazy-name-hash: fix compilation Stefan Beller
2018-01-03  1:12         ` [PATCH 2/5] t/lib-submodule-update.sh: clarify test Stefan Beller
2018-01-03  1:12         ` [PATCH 3/5] t/lib-submodule-update.sh: Fix test ignoring ignored files in submodules Stefan Beller
2018-01-03  1:12         ` [PATCH 4/5] unpack-trees: oneway_merge to update submodules Stefan Beller
2018-01-03  1:12         ` [PATCH 5/5] submodule: submodule_move_head omits old argument in forced case Stefan Beller
2018-01-03 20:49         ` [PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes Junio C Hamano
2018-01-03 21:16           ` Stefan Beller [this message]
2018-01-05 20:03           ` [PATCHv4 0/4] " Stefan Beller
2018-01-05 20:03             ` [PATCHv4 1/4] t/lib-submodule-update.sh: clarify test Stefan Beller
2018-01-05 20:03             ` [PATCHv4 2/4] t/lib-submodule-update.sh: Fix test ignoring ignored files in submodules Stefan Beller
2018-01-05 20:03             ` [PATCHv4 3/4] unpack-trees: oneway_merge to update submodules Stefan Beller
2018-01-05 20:03             ` [PATCHv4 4/4] submodule: submodule_move_head omits old argument in forced case Stefan Beller
2018-01-09 22:45             ` [PATCHv4 0/4] Fix --recurse-submodules for submodule worktree changes Junio C Hamano
2017-12-27 22:57   ` [PATCHv2 5/5] submodule: submodule_move_head omits old argument in forced case Stefan Beller

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