Re: Compiling python 3.12 with bzip2

[Caolán McNamara <caolan.mcnamara@xxxxxxxxxxxxx>]

On Mon, 2024-12-30 at 16:45 +0100, Xisco Fauli wrote:
> Hello,
> 
> In https://gerrit.libreoffice.org/c/core/+/178681 I'm trying to
> upgrade internal python to 3.11. Unfortunately it fails to link _bz2
> extension
...
> Any idea how to fix it ?

I think, from:

make verbose=true python3.build > /tmp/thelog

that the link line used is something like:

$ clang ... Modules/_bz2module.c -o ... Modules/_bz2module.o

where I see -I and -L entries for internal bzip2 but no actual -lbz2 to
link against the libbz2.a I see in workdir/UnpackedTarball/bzip2

Checking the python config.log in workdir/UnpackedTarball/python3
then around line 14248 there is:

configure:16228: checking for ZLIB
configure:16545: result: yes
configure:16576: checking for BZIP2
configure:16799: result: yes

which is a little "bare", but at line 27480 there is:

ac_cv_env_ZLIB_LIBS_set=set
ac_cv_env_ZLIB_LIBS_value='   -lz'

vs

ac_cv_env_BZIP2_LIBS_set=set
ac_cv_env_BZIP2_LIBS_value='   '

so I suspect an injection of "BZIP2_LIBS" in the environment that
python's configure is run inside is overriding python's configure from
determining it on its own and it just takes what it sees from an env
variable.

git grep on BZIP2_LIBS gives some hits, and I think the relevant ones
are in the toplevel configure.ac where we have:

AC_SUBST(BZIP2_LIBS)

which for the default non-system bzip2 is empty and I think that's the
issue seeing as for the similar ZLIB_LIBS case we explicitly set
something in there for the non-system zlib case.

I've hazarded something that I pushed to your
https://gerrit.libreoffice.org/c/core/+/178681
and maybe it will help