Subject: Re: [PATCH] Allow PERL_PATH="/usr/bin/env perl"

From: Bryan Larsen <[email-masked]>
Date: Thu, 03 May 2007 18:58:00 -0400

Shawn O. Pearce wrote:
> Bryan Larsen <[email-masked]> wrote:
>> The perl scripts start with "#!/usr/bin/perl".  There is a mechanism 
>> PERL_PATH in the Makefile to change this, but it currently doesn't work 
>> with PERL_PATH="/usr/bin/env perl".  This is causing problems in 
>> MacPorts, where we wish to work with the MacPorts perl if it is 
>> installed, but fall back to the system perl if it isn't.
>>
>> Signed-off-by: Bryan Larsen <[email-masked]>
>> ---
>>  perl/Makefile |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/perl/Makefile b/perl/Makefile
>> index 17d004e..2832cb4 100644
>> --- a/perl/Makefile
>> +++ b/perl/Makefile
>> @@ -33,7 +33,7 @@ $(makfile): ../GIT-CFLAGS Makefile
>>         echo '  echo $(instdir_SQ)' >> $@
>>  else
>>  $(makfile): Makefile.PL ../GIT-CFLAGS
>> -       '$(PERL_PATH_SQ)' $< PREFIX='$(prefix_SQ)'
>> +       $(PERL_PATH_SQ) $< PREFIX='$(prefix_SQ)'
>>  endif
> 
> This will break if someone actually had ' in their PERL_PATH:
> 
> 	PERL_PATH="/path'to'perl"
> 
> as PERL_PATH_SQ tries to close the single quoted string you don't
> open anymore.  That is because it is defined to be PERL_PATH,
> but with all ' replaced by '\''.

Actually, we should just use $(PERL_PATH) with no _SQ and no quotes. 
The user is passing in something that is designed to go in a shebang 
line: their funny characters are going to be interpreted by the 
interactive shell to load the perl interpreter; we want "make" to do the 
same thing.

> 
> This change also breaks for anyone who had spaces in their PERL_PATH.

Actually a space didn't work before, but with my patch it works like 
you'd expect in a shebang line, as the delimiter between the command and 
it's arguments.

> 
> Can I ask why you can't just supply a small wrapper shellscript
> with MacPorts
> 
> 	cat >perl <<EOF
> 	#!/bin/sh
> 	exec env perl "$@"
> 	EOF
> 	chmod a+x perl
> 
> ?  Or better yet, supply Git the correct Perl path?  If/when we ever
> go to native Perl libraries again a Git Perl library compiled for
> the system perl may not work later when the user installs a newer
> MacPorts perl.  Switching automatically to the MacPorts perl without
> recompiling the native extensions is a little evil...
> 

At that point we just add a single line "depends_lib port:perl5.8" to 
the Portfile and everything magically works for the user.  Right now 
it's only in the git-svnimport part of the Portfile, which is nice: the 
user doesn't get multiple megabytes worth of perl unless we also need to 
install p5-svn-simple.

An even better fix can be to drop PERL_PATH from the Makefile and 
replace the shebang line with "#!/usr/bin/env perl".  Much simpler, and 
the right thing to do, in my opinion.

cheers,
Bryan