Subject: Re: [PATCH/RFC] Changing submodule foreach --recursive to be depth-first, --parent option to execute command in supermodule as well

From: Jens Lehmann <[email-masked]>
Date: Mon, 18 Mar 2013 22:10:43 +0100

Am 12.03.2013 17:01, schrieb Phil Hord:
> On Sat, Mar 9, 2013 at 1:18 PM, Jens Lehmann <[email-masked]> wrote:
>> Am 05.03.2013 22:17, schrieb Phil Hord:
>>> On Tue, Mar 5, 2013 at 3:51 PM, Jens Lehmann <[email-masked]> wrote:
>>>> Am 05.03.2013 19:34, schrieb Junio C Hamano:
>>>>> Eric Cousineau <[email-masked]> writes:
>>>>>> ...
>>>>> I am not entirely convinced we would want --include-super in the
>>>>> first place, though.  It does not belong to "submodule foreach";
>>>>> it is doing something _outside_ the submoudules.
>>>>
>>>> I totally agree with that. First, adding --include-super does not
>>>> belong into the --post-order patch at all, as that is a different
>>>> topic (even though it belongs to the same use case Eric has). Also
>>>> the reason why we are thinking about adding the --post-order option
>>>> IMO cuts the other way for --include-super: It is so easy to do
>>>> that yourself I'm not convinced we should add an extra option to
>>>> foreach for that, especially as it has nothing to do with submodules.
>>>> So I think we should just drop --include-super.
>>>
>>> I agree it should not be part of this commit, but I've often found
>>> myself in need of an --include-super switch.   To me,
>>> git-submodule-foreach means "visit all my .git repos in this project
>>> and execute $cmd".  It's a pity that the super-project is considered a
>>> second-class citizen in this regard.
>>
>> Hmm, for me the super-project is a very natural second-class citizen
>> to "git *submodule* foreach". But also I understand that sometimes the
>> user wants to apply a command to superproject and submodules alike (I
>> just recently did exactly that with "git gc" on our build server).
>>
>>> I have to do this sometimes:
>>>
>>>    ${cmd} && git submodule foreach --recursive '${cmd}'
>>>
>>> I often forget the first part in scripts, though, and I've seen others
>>> do it too.  I usually create a function for it in git-heavy scripts.
>>>
>>> In a shell, it usually goes like this:
>>>
>>>    git submodule foreach --recursive '${cmd}'
>>>    <up><home><del>{30-ish}<end><backspace><enter>
>>>
>>> It'd be easier if I could just include a switch for this, and maybe
>>> even create an alias for it.  But maybe this is different command
>>> altogether.
>>
>> Are you sure you wouldn't forget to provide such a switch too? ;-)
> 
> No.  However, when I remember to add the switch, my shell history will
> remember it for me.  This does not happen naturally for me in the
> "<up><home><del>{30-ish}..." workflow.

I started to use '&&' in my daily shell work for exactly that reason:
that the bash history remembers groups of two or more commands for me.

> I also hope this switch grows up into a configuration option someday.
> Or maybe a completely different command, like I said before; because I
> actually think it could be dangerous as a configuration option since
> it would have drastic consequences for users executing scripts or
> commands in other users' environments.

I agree on the possible problems a configuration option introduces.

>> I'm still not convinced we should add a new switch, as it can easily
>> be achieved by adding "${cmd} &&" to your scripts. And on the command
>> line you could use an alias like this one to achieve that:
>>
>> [alias]
>>         recurse = !sh -c \"$@ && git submodule foreach --recursive $@\"
> 
> Yes, making the feature itself a 2nd-class citizen.  :-)
> 
> But this alias also denies me the benefit of the --post-order option.
> For 'git recurse git push', for example, I wouldn't want the
> superproject push to occur first; I would want it to occur last after
> the submodules have been successfully pushed.

[alias]
         recurse-post = !sh -c \"git submodule foreach --recursive --post-order $@ && $@\"
;-)

> I agree this should go in some other commit, but I do not think it is
> so trivial it should never be considered as a feature for git.  That's
> all I'm trying to say.

I am not against adding such a functionality to Git, I'm just not
convinced "git submodule foreach" is the right command for that. I
suspect the "git for-each-repo" Lars proposed earlier this year might
be a better choice, as that could also recurse into other repos which
aren't registered as submodules. And a "for-each-repo" to me looks
like a command which could include the superproject too (at least when
told to do so with an option).