Git and PCRE2 vs PCRE?

Git and PCRE2 vs PCRE?

[Jeffrey Walton]

Some more 2.12.2 testing on Solaris 11.3 x86_64:

    ...
    CC ident.o
    CC kwset.o
    CC line-log.o
    CC levenshtein.o
    CC line-range.o
    CC list-objects.o
In file included from revision.h:5:0,
                 from line-log.c:10:
grep.h:5:18: fatal error: pcre.h: No such file or directory
 #include <pcre.h>
                  ^
compilation terminated.
gmake: *** [line-log.o] Error 1


Configure has an option for libpcre, but its not clear to me how to
fine tune it for libpcre2:

$ ./configure --help | /usr/gnu/bin/grep -A 2 -i pcre
  --with-libpcre          support Perl-compatible regexes (default is NO)
                          ARG can be also prefix for libpcre library and
                          headers

Is it possible to use PCRE2 with Git? If so, how do I tell Git to use PCRE2?

Thanks in advance.

**********

$ ls /usr/local/include/pcre*
/usr/local/include/pcre2.h       /usr/local/include/pcre2posix.h

$ ls /usr/local/lib64/libpcre*
/usr/local/lib64/libpcre2-16.a
/usr/local/lib64/libpcre2-16.la
/usr/local/lib64/libpcre2-16.so
/usr/local/lib64/libpcre2-16.so.0
/usr/local/lib64/libpcre2-16.so.0.5.0
/usr/local/lib64/libpcre2-32.a
/usr/local/lib64/libpcre2-32.la
/usr/local/lib64/libpcre2-32.so
/usr/local/lib64/libpcre2-32.so.0
/usr/local/lib64/libpcre2-32.so.0.5.0
/usr/local/lib64/libpcre2-8.a
/usr/local/lib64/libpcre2-8.la
/usr/local/lib64/libpcre2-8.so
/usr/local/lib64/libpcre2-8.so.0
/usr/local/lib64/libpcre2-8.so.0.5.0
/usr/local/lib64/libpcre2-posix.a
/usr/local/lib64/libpcre2-posix.la
/usr/local/lib64/libpcre2-posix.so
/usr/local/lib64/libpcre2-posix.so.1
/usr/local/lib64/libpcre2-posix.so.1.0.1

Re: Git and PCRE2 vs PCRE?

[Jeff King]

On Thu, Mar 30, 2017 at 04:59:27PM -0400, Jeffrey Walton wrote:

> Configure has an option for libpcre, but its not clear to me how to
> fine tune it for libpcre2:
> 
> $ ./configure --help | /usr/gnu/bin/grep -A 2 -i pcre
>   --with-libpcre          support Perl-compatible regexes (default is NO)
>                           ARG can be also prefix for libpcre library and
>                           headers
> 
> Is it possible to use PCRE2 with Git? If so, how do I tell Git to use PCRE2?

No, I don't think so. According to the release announcement for pcre2,
the API is not compatible with the original:

  https://lists.exim.org/lurker/message/20150105.162835.0666407a.en.html

So even if you could tweak the build to use it, it would not do the
right thing. Somebody would have to add code for the new library, and
probably have a USE_LIBPCRE2 flag.

I don't know offhand if there are compelling reasons to do that work.

-Peff

Re: Git and PCRE2 vs PCRE?

[Junio C Hamano]

Jeffrey Walton <noloader@gmail.com> writes:

> Is it possible to use PCRE2 with Git? If so, how do I tell Git to use PCRE2?

Given that pcre2's symbols are all prefixed with pcre2_ (I only
checked http://www.pcre.org/current/doc/html/pcre2api.html) and we
do not see any hits from "git grep pcre2", I do not think you can
just "configure" Git to use it.  Unless pcre2 library has a drop-in
replacement backward compatibility mode with pcre library, that is.

It probably is possible to use PCRE2 with Git by adding similar
amount of code to grep.[ch] as we have support for pcre and that
would be the way you tell Git to use PCRE2, but I think that is
probably not the questino you are asking.

Re: Git and PCRE2 vs PCRE?

[Jeffrey Walton]

On Thu, Mar 30, 2017 at 5:23 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Jeffrey Walton <noloader@gmail.com> writes:
>
>> Is it possible to use PCRE2 with Git? If so, how do I tell Git to use PCRE2?
>
> Given that pcre2's symbols are all prefixed with pcre2_ (I only
> checked http://www.pcre.org/current/doc/html/pcre2api.html) and we
> do not see any hits from "git grep pcre2", I do not think you can
> just "configure" Git to use it.  Unless pcre2 library has a drop-in
> replacement backward compatibility mode with pcre library, that is.
>
> It probably is possible to use PCRE2 with Git by adding similar
> amount of code to grep.[ch] as we have support for pcre and that
> would be the way you tell Git to use PCRE2, but I think that is
> probably not the questino you are asking.

Ack, thanks Jeff and Junio. Its no big deal to me.

I'm not a PCRE user, so I'm not familiar with the extra gyrations
needed for the migration.

I'll get the original PCRE installed.

Thanks again.