Re: [PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes

[Stefan Beller]

On Wed, Jan 3, 2018 at 12:49 PM, Junio C Hamano  wrote:
> Stefan Beller  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.
>
>

Re: [PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes

[Junio C Hamano]

Stefan Beller  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".

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

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.

> 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.

[PATCHv3 0/5] Fix --recurse-submodules for submodule worktree changes

[Stefan Beller]

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);


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.

The test added in the last patch got slightly larger as now we also test for
newly staged files to be blown away in the submodule.

v1:

The fix is in the last patch, the first patches are just massaging the code
base to make the fix easy.

The second patch fixes a bug in the test, which was ineffective at testing.
The third patch shows the problem this series addresses,
the fourth patch is a little refactoring, which I want to keep separate
as I would expect it to be a performance regression[1].
The first patch is unrelated, but improves the readability of submodule test
cases, which we'd want to improve further.

Thanks,
Stefan


Stefan Beller (5):
  t/helper/test-lazy-name-hash: fix compilation
  t/lib-submodule-update.sh: clarify test
  t/lib-submodule-update.sh: Fix test ignoring ignored files in
submodules
  unpack-trees: oneway_merge to update submodules
  submodule: submodule_move_head omits old argument in forced case

 submodule.c |  4 +++-
 t/helper/test-lazy-init-name-hash.c |  2 +-
 t/lib-submodule-update.sh   | 19 +--
 unpack-trees.c  |  3 +++
 4 files changed, 24 insertions(+), 4 deletions(-)

-- 
2.15.1.620.gb9897f4670-goog