Systems with old regex system headers/libraries don't pick up git's compat/regex header file

Systems with old regex system headers/libraries don't pick up git's compat/regex header file

[Richard Lloyd]

git ships with a compat/regex tree containing a recent regex
release, presumably with the intention of allowing systems with
either no regex or an old regex installed to use the newer compat
version.

With the release of git-2.10.1, the use of a recent regex
is now specifically checked in git-compat-util.h via a
#ifndef REG_STARTEND check at line 979.

Unfortunately, on systems with an older regex shipped as
standard (e.g. HP-UX 11), the include path picks up
/usr/include/regex.h first, which doesn't define REG_STARTEND
and the git-compat-util.h check fails.

The fix I applied on HP-UX 11 was to add -Icompat/regex
to the CFLAGS ahead of other -I directives. Another possible
change needed might be to line 69 of compat/regex/regex.c:

#include "regex.h"

This is to ensure that /usr/include/regex.h isn't picked up
(since git ships its own regex.h in the compat/regex
dir, it probably shouldn't #include <regex.h> anyway,
which risks picking up an incompatible regex.h).

Richard K. Lloyd,           E-mail: richard.lloyd@connectinternetsolutions.com
Connect Internet Solutions,    WWW: https://www.connectinternetsolutions.com/
4th Floor, New Barratt House,
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Liverpool,
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Re: Systems with old regex system headers/libraries don't pick up git's compat/regex header file

[Junio C Hamano]

Richard Lloyd <richard.lloyd@connectinternetsolutions.com> writes:

> git ships with a compat/regex tree containing a recent regex
> release, presumably with the intention of allowing systems with
> either no regex or an old regex installed to use the newer compat
> version.

Quick question.  Does NO_REGEX help?  cf. Makefile

# Define NO_REGEX if your C library lacks regex support with REG_STARTEND
# feature.

Re: Systems with old regex system headers/libraries don't pick up git's compat/regex header file

[Jeff King]

On Thu, Oct 06, 2016 at 10:15:49AM +0100, Richard Lloyd wrote:

> Unfortunately, on systems with an older regex shipped as
> standard (e.g. HP-UX 11), the include path picks up
> /usr/include/regex.h first, which doesn't define REG_STARTEND
> and the git-compat-util.h check fails.
> 
> The fix I applied on HP-UX 11 was to add -Icompat/regex
> to the CFLAGS ahead of other -I directives. Another possible
> change needed might be to line 69 of compat/regex/regex.c:

Junio mentioned the NO_REGEX knob in the Makefile. If that works for
you, the next step is probably to add a line to the HP-UX section of
config.mak.uname, so that it just works out of the box.

-Peff

Re: Systems with old regex system headers/libraries don't pick up git's compat/regex header file

[Richard Lloyd]

On 06/10/16 20:11, Jeff King wrote:
> Junio mentioned the NO_REGEX knob in the Makefile. If that works for
> you, the next step is probably to add a line to the HP-UX section of
> config.mak.uname, so that it just works out of the box.

This doesn't work because the check in git-compat-util.h only looks
for REG_STARTEND being defined (if it isn't, it #error's out).

That define is not mentioned anywhere else other than in the
compat/regex tree, which is why I used -Icompat/regex to pick up
<regex.h> from there - this was the "easiest" solution for me on
HP-UX 11.

Note that with this inclusion change, the source compiled and linked
fine on HP-UX 11 and git passed its tests, including the regex-based ones.

Richard K. Lloyd,           E-mail: richard.lloyd@connectinternetsolutions.com
Connect Internet Solutions,    WWW: https://www.connectinternetsolutions.com/
4th Floor, New Barratt House,
47, North John Street,
Liverpool,
Merseyside, UK. L2 6SG




>
> -Peff
>




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Re: Systems with old regex system headers/libraries don't pick up git's compat/regex header file

[Jeff King]

On Fri, Oct 07, 2016 at 04:45:08PM +0100, Richard Lloyd wrote:

> On 06/10/16 20:11, Jeff King wrote:
> > Junio mentioned the NO_REGEX knob in the Makefile. If that works for
> > you, the next step is probably to add a line to the HP-UX section of
> > config.mak.uname, so that it just works out of the box.
> 
> This doesn't work because the check in git-compat-util.h only looks
> for REG_STARTEND being defined (if it isn't, it #error's out).
> 
> That define is not mentioned anywhere else other than in the
> compat/regex tree, which is why I used -Icompat/regex to pick up
> <regex.h> from there - this was the "easiest" solution for me on
> HP-UX 11.

I'm confused. Setting NO_REGEX in the Makefile will add -Icompat/regex
to your compiler invocation. So git-compat-util.h should pick up our
compat regex routines, which _do_ have REG_STARTEND.

How are you building? Doing:

  make NO_REGEX=1

is supposed to work, and if it doesn't, there's a bug.

-Peff