Re: maint.mk bug (with tentative fix)

[Gary V. Vaughan]

Hi Jim,

Thanks for the quick response.

On Jan 2, 2014, at 2:27 PM, Jim Meyering <address@hidden> wrote:

> On Wed, Jan 1, 2014 at 5:08 PM, Gary V. Vaughan <address@hidden> wrote:
> ...
>> The change (back ticks instead of $(...) in the no-submodule-changes rule) 
>> looks like a harmless way to fix the bug to me.
>> 
>> Okay to push?
> 
> Hi Gary,
> I have been unable to reproduce that failure so far.
> E.g., this via grep (which I have just updated to use the latest from gnulib):
> 
>    make no-submodule-changes SHELL=/bin/bash V=1
> 
> works fine for me using this version of bash and others:
> 
>    GNU bash, version 4.2.45(2)-release (i386-apple-darwin12.3.0)
> 
> Many people run rules that depend on the one you're proposing
> to change, so I suspect that something unusual about your environment is
> at the root of this.
> 
> Besides, you know how I feel about backticks vs $()
> syntax (we should almost always prefer the latter), so am very reluctant
> to make such changes without understanding the root cause.

Okay...  On a whim, I decided to build my own GNU make, and it turns out that
this seems to be a problem with the Apple make build shipped with latest Xcode
command-line tools for (at least) Mavericks 10.9.1 - even though the version
string indicates the build was rolled at least a couple of releases ago.

$ make --version
GNU Make 3.81
Copyright (C) 2006  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

This program built for i386-apple-darwin11.3.0

make V=1 no-submodule-changes SHELL=/bin/bash
if test -d ./.git                               \
                && git --version >/dev/null 2>&1; then                  \
          diff=$(cd . && git submodule -q foreach git diff-index --name-only 
HEAD)            \
            || exit 1;                                                  \
          case $diff in '') ;;                                          \
            *) echo 'maint.mk: submodule files are locally modified:';  \
                echo "$diff"; exit 1;; esac;                            \
        else                                                            \
          : ;                                                           \
        fi
/bin/bash: -c: line 1: syntax error: unexpected end of file
make: *** [no-submodule-changes] Error 2

$ gmake --version
GNU Make 4.0
Built for x86_64-apple-darwin13.0.0
Copyright (C) 1988-2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

$ gmake V=1 no-submodule-changes SHELL=/bin/bash
if test -d ./.git                               \
        && git --version >/dev/null 2>&1; then                  \
  diff=$(cd . && git submodule -q foreach git diff-index --name-only
HEAD)                      \
    || exit 1;                                                  \
  case $diff in '') ;;                                          \
    *) echo 'maint.mk: submodule files are locally modified:';  \
        echo "$diff"; exit 1;; esac;                            \
else                                                            \
  : ;                                                           \
fi
My hunch about nested parens being the misparsed by Apple's latest make was
correct, so if you prefer to avoid back ticks entirely, I can pull srcdir out
of the command substitution for an equivalent fix that also works.

$ make V=1 no-submodule-changes-portable SHELL=/bin/bash
if test -d ./.git                               \
                && git --version >/dev/null 2>&1; then                  \
          srcdir=.;                                             \
          diff=$(cd $srcdir && git submodule -q foreach git diff-index 
--name-only HEAD)            \
            || exit 1;                                                  \
          case $diff in '') ;;                                          \
            *) echo 'maint.mk: submodule files are locally modified:';  \
                echo "$diff"; exit 1;; esac;                            \
        else                                                            \
          : ;                                                           \
        fi

I'd like to think enough of us are using Macs for GNU development that it's
less effort overall to workaround the weird parser bug in maint.mk than force
everyone to figure out why they need a custom build of GNU make on Mac OS for
this rule not to error out.

Okay to push one of the above (backticks or pull srcdir out of the $() at your
preference) along with a comment that Apple ships a buggy make with recent Mac 
OS
releases?

Cheers,
-- 
Gary V. Vaughan (gary AT gnu DOT org)

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