[bug] 2.5.0 build with NO_PERL is broken

> 
> I was working on update git on FreeBSD ports tree to 2.5.0 and I noted 2.5.0
> is trying to use perl even when it's being built with NO_PERL knob.
> 
> /bin/sh: /usr/bin/perl: not found
> Makefile:1701: recipe for target 'common-cmds.h' failed
> gmake[2]: *** [common-cmds.h] Error 127
> gmake[2]: *** Waiting for unfinished jobs....
> gmake[2]: Leaving directory '/freebsd/ports/head/devel/git/work/git-2.5.0'
> 
> After a quick search, looks like commit 527ec3980b is the culprit since it
> removed generate-cmdlist.sh and introduced generate-cmdlist.perl.
> 
> I just would like to check if it's planned to add perl dependency during
> build time or it happened by accident and will be fixed so NO_PERL can work
> again.

> I also found that some commands require perl when NO_PERL is set:
>
> git-submodule
> git-request-pull
> git-am
>
> Definitely NO_PERL is not working as expected.

> Renato Botelho <garga@FreeBSD.org> writes:
>> I also found that some commands require perl when NO_PERL is set:
>
> NO_PERL merely means "I want to build a subset of Git that is meant
> to be usable on a system without a working Perl installed".  These
> scripts that do require Perl installed are indeed not expected to
> work under NO_PERL (if you think about it, that would be natural and
> the only sensible expectation---otherwise we would have coded them
> without using Perl at all, in which case there will be no need for
> NO_PERL in the first place).

> Eric Sunshine <sunshine@sunshineco.com> writes:
>> Nevertheless, there's still the problem, due to 527ec39
>> (generate-cmdlist: parse common group commands, 2015-05-21), that git
>> doesn't build at all anymore when Perl is unavailable.
>
> I do not think that is anything new.  We always have assumed "some"
> version of Perl available in order to run t/ scripts.

> On Fri, Aug 14, 2015 at 5:02 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Eric Sunshine <sunshine@sunshineco.com> writes:
>>> Nevertheless, there's still the problem, due to 527ec39
>>> (generate-cmdlist: parse common group commands, 2015-05-21), that git
>>> doesn't build at all anymore when Perl is unavailable.
>>
>> I do not think that is anything new.  We always have assumed "some"
>> version of Perl available in order to run t/ scripts.
>
> True, but prior to 527ec39, without Perl available, git itself could
> at least be built and used (with some commands unavailable), even if
> it couldn't be fully tested. As of 527ec39, however, git won't even
> build because common-cmds.h can't be generated.

> Eric Sunshine <sunshine@sunshineco.com> writes:
>
>> On Fri, Aug 14, 2015 at 5:02 PM, Junio C Hamano <gitster@pobox.com> wrote:
>>> Eric Sunshine <sunshine@sunshineco.com> writes:
>>>> Nevertheless, there's still the problem, due to 527ec39
>>>> (generate-cmdlist: parse common group commands, 2015-05-21), that git
>>>> doesn't build at all anymore when Perl is unavailable.
>>>
>>> I do not think that is anything new.  We always have assumed "some"
>>> version of Perl available in order to run t/ scripts.
>>
>> True, but prior to 527ec39, without Perl available, git itself could
>> at least be built and used (with some commands unavailable), even if
>> it couldn't be fully tested. As of 527ec39, however, git won't even
>> build because common-cmds.h can't be generated.
>
> I wouldn't bother digging in the history myself, but I am reasonably
> sure that the current genereate-common-cmds is not the sole instance
> that we relied on Perl to build (not test) in the past, and that is
> another reason why I do not think this is anything new.

> >>> Eric Sunshine <sunshine <at> sunshineco.com> writes:
> >>>
> >>> I do not think that is anything new.  We always have assumed "some"
> >>> version of Perl available in order to run t/ scripts.
> >>
> >> True, but prior to 527ec39, without Perl available, git itself could
> >> at least be built and used (with some commands unavailable), even if
> >> it couldn't be fully tested. As of 527ec39, however, git won't even
> >> build because common-cmds.h can't be generated.
> >
> > I wouldn't bother digging in the history myself, but I am reasonably
> > sure that the current genereate-common-cmds is not the sole instance
> > that we relied on Perl to build (not test) in the past, and that is
> > another reason why I do not think this is anything new.
> 
> Hmm. In my tests by setting PERL_PATH to a bogus (non-existent)
> command, prior to 527ec39, git builds successfully, whereas, following
> 527ec39, it does not build. But, perhaps I overlooked something...(?)

> Eric Sunshine <sunshine <at> sunshineco.com> writes:
>> On Fri, Aug 14, 2015 at 6:22 PM, Junio C Hamano <gitster <at> pobox.com>
> wrote:
>> > Eric Sunshine <sunshine <at> sunshineco.com> writes:
>> >> On Fri, Aug 14, 2015 at 5:02 PM, Junio C Hamano <gitster <at>
> pobox.com> wrote:
>> >>> Eric Sunshine <sunshine <at> sunshineco.com> writes:
>> >>> I do not think that is anything new.  We always have assumed "some"
>> >>> version of Perl available in order to run t/ scripts.
>> >>
>> >> True, but prior to 527ec39, without Perl available, git itself could
>> >> at least be built and used (with some commands unavailable), even if
>> >> it couldn't be fully tested. As of 527ec39, however, git won't even
>> >> build because common-cmds.h can't be generated.
>> >
>> > I wouldn't bother digging in the history myself, but I am reasonably
>> > sure that the current genereate-common-cmds is not the sole instance
>> > that we relied on Perl to build (not test) in the past, and that is
>> > another reason why I do not think this is anything new.
>>
>> Hmm. In my tests by setting PERL_PATH to a bogus (non-existent)
>> command, prior to 527ec39, git builds successfully, whereas, following
>> 527ec39, it does not build. But, perhaps I overlooked something...(?)
>
> It builds but there will be at least 3 commands that won't work:

> Eric Sunshine <sunshine <at> sunshineco.com> writes:
> 
> Hmm, I was under the impression from your initial mail[1] that Git
> wouldn't even build without Perl available:
> 
>     /bin/sh: /usr/bin/perl: not found
>     Makefile:1701: recipe for target 'common-cmds.h' failed
>     gmake[2]: *** [common-cmds.h] Error 127

> Doesn't this failure prevent generation of the 'git' executable altogether?
> 
> > git-submodule
> > git-request-pull
> > git-am
> 
> Also...
> 
> git-add--interactive
> git-archimport
> git-cvsexportcommit
> git-cvsimport
> git-cvsserver
> git-difftool
> git-instaweb
> git-relink
> git-send-email
> git-svn