Re: "submodule foreach" much slower than removed "submodule--helper --list"
Replying to both this & the parent post:
On Sat, Oct 15 2022, Jonas Bernoulli wrote:
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> In v2.38.0 (31955475d1c283120d5d84247eb3fd55d9f5fdd9)
> "submodule--helper --list" was remove because
>
>> We're not getting anything useful from the "list | cut -f2"
>> invocation that we couldn't get from "foreach 'echo $sm_path'".
>
> But we get speed (this is with about one hundred modules):
>
> $ time git submodule foreach -q 'echo $sm_path' > /dev/null
>
> real 0m0.585s
> user 0m0.413s
> sys 0m0.182s
>
> $ time git submodule--helper list > /dev/null
>
> real 0m0.008s
> user 0m0.004s
> sys 0m0.004s
>
> Please consider restoring this subcommand or providing something
> equivalent that is just as fast.
Sorry about the slowdown, the removal of "list" was just an in-between step to migrating "submodule" to a full built-in.
I can't reproduce anything like the 8ms v.s. ~600ms difference you note here, but for me migrating it to a built-in is around 10% slower with "foreach" than the old "list". I wonder what results you get?
I sent in a topic to migrate it since you sent this report. I was going to do it in this development cycle, but this prompted me to do it earlier:
https://lore.kernel.org/git/cover-00.10-00000000000-20221017T115544Z-avarab@gmail.com/
On Sat, Oct 15 2022, Jonas Bernoulli wrote:
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> I just noticed that "submodule--helper name" was also removed, which I
> also found useful in scripts. Please tell me if I am missing something,
> but it seems I now have to do something like this instead:
>
> git config -f .gitmodules --list |
> sed -n "s|^submodule.\([^.]*\).path=$path\$|\1|p"
>
> The old way was nicer:
>
> git submodule--helper name $path
>
> I realize submodule--helper is for internal use and using it anyway
> comes with the risk of such removals and other changes, but again,
> please consider restoring that or providing something similar in the
> public interface.
This however is another case, I removed "name" along with "list" and other leftover code we weren't using anymore for the internal-only "submodule--helper" (which is at turns out, was not as internal-only as we'd hoped).
For "list" it's clear how to use "foreach" instead, but for "name" then AFAICT the "best" replacement is to do a:
git submodule foreach 'echo $displaypath $name'
And pipe that into grep/sed. If that's fast enough would it satisfy your use-case, or would a "name" equivalent be handy?
I think the best way to prove that would be e.g.:
git submodule foreach-format '%{name}' -- <pathspec>Which, due to the "foreach" taking N number of arguments isn't easy to add to "foreach" without the interface becoming somewhat tortured (we could add a [---pathspec=<pathspec>]...), but "-- <pathspec>" with a different subcommand name seems better.
Jonas Bernoulli
