Build failure on 32-bit OS: incompatible type in tp_hash in PyTypeObject

[hosiet]

Current mod_python v3.5.0.6 fails to build on 32-bit OS (e.g., armhf, i386, ...):

• Build log: https://buildd.debian.org/status/fetch.php?pkg=libapache2-mod-python&arch=i386&ver=3.5.0.6-1&stamp=1767544870&raw=0

Building mod_python.so.

/usr/bin/apxs2 -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13 -Wc,-ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=.  -c mod_python.c _apachemodule.c requestobject.c tableobject.c util.c serverobject.c connobject.c filterobject.c hlist.c hlistobject.c finfoobject.c version.c include/_apachemodule.h  include/filterobject.h  include/hlist.h include/mod_python.h  include/psp_flex.h include/psp_parser.h include/requestobject.h include/tableobject.h include/connobject.h include/finfoobject.h include/hlistobject.h include/mp_version.h include/_pspmodule.h  include/psp_string.h  include/serverobject.h include/util.h -L/usr/lib/python3.13/config-3.13-i386-linux-gnu -L/usr/lib/i386-linux-gnu -lpython3.13 -ldl  -lm   
/usr/share/apr-1.0/build/libtool  --mode=compile --tag=disable-static i686-linux-gnu-gcc -prefer-pic -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security  -Wdate-time -D_FORTIFY_SOURCE=2   -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE   -I/usr/include/apache2  -I/usr/include/apr-1.0   -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13  -c -o mod_python.lo mod_python.c && touch mod_python.slo
libtool: compile:  i686-linux-gnu-gcc -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -I/usr/include/apache2 -I/usr/include/apr-1.0 -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13 -c mod_python.c  -fPIC -DPIC -o .libs/mod_python.o
/usr/share/apr-1.0/build/libtool  --mode=compile --tag=disable-static i686-linux-gnu-gcc -prefer-pic -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security  -Wdate-time -D_FORTIFY_SOURCE=2   -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE   -I/usr/include/apache2  -I/usr/include/apr-1.0   -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13  -c -o _apachemodule.lo _apachemodule.c && touch _apachemodule.slo
libtool: compile:  i686-linux-gnu-gcc -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -I/usr/include/apache2 -I/usr/include/apr-1.0 -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13 -c _apachemodule.c  -fPIC -DPIC -o .libs/_apachemodule.o
/usr/share/apr-1.0/build/libtool  --mode=compile --tag=disable-static i686-linux-gnu-gcc -prefer-pic -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security  -Wdate-time -D_FORTIFY_SOURCE=2   -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE   -I/usr/include/apache2  -I/usr/include/apr-1.0   -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13  -c -o requestobject.lo requestobject.c && touch requestobject.slo
libtool: compile:  i686-linux-gnu-gcc -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -I/usr/include/apache2 -I/usr/include/apr-1.0 -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13 -c requestobject.c  -fPIC -DPIC -o .libs/requestobject.o
/usr/share/apr-1.0/build/libtool  --mode=compile --tag=disable-static i686-linux-gnu-gcc -prefer-pic -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security  -Wdate-time -D_FORTIFY_SOURCE=2   -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE   -I/usr/include/apache2  -I/usr/include/apr-1.0   -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13  -c -o tableobject.lo tableobject.c && touch tableobject.slo
libtool: compile:  i686-linux-gnu-gcc -pipe -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -DLINUX -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -I/usr/include/apache2 -I/usr/include/apr-1.0 -I/usr/include/apr-1.0 -I/usr/include -ffile-prefix-map=/build/reproducible-path/libapache2-mod-python-3.5.0.6=. -I/build/reproducible-path/libapache2-mod-python-3.5.0.6/src/include -I/usr/include/python3.13 -I/usr/include/python3.13 -c tableobject.c  -fPIC -DPIC -o .libs/tableobject.o
tableobject.c:1203:5: error: initialization of 'Py_hash_t (*)(PyObject *)' {aka 'int (*)(struct _object *)'} from incompatible pointer type 'long int (*)(PyObject *)' {aka 'long int (*)(struct _object *)'} [-Wincompatible-pointer-types]
 1203 |     table_nohash,                       /* tp_hash */
      |     ^~~~~~~~~~~~
tableobject.c:1203:5: note: (near initialization for 'MpTable_Type.tp_hash')
tableobject.c:1161:13: note: 'table_nohash' declared here
 1161 | static long table_nohash(PyObject *self)
      |             ^~~~~~~~~~~~
apxs:Error: Command failed with rc=65536
.
make[3]: *** [Makefile:57: mod_python.so] Error 1

The reason is that *hashfunc as defined in https://docs.python.org/3/c-api/typeobj.html#c.hashfunc has type Py_hash_t, which is of type signed integer as defined at https://docs.python.org/3/c-api/hash.html#c.Py_hash_t . However, in

mod_python/src/tableobject.c

Line 1161 in 52f8975

static long table_nohash(PyObject *self)

you are using long instead. On 32-bit OS, long may not equal to int and thus the build error happens.

The solution could be directly using Py_hash_t, instead of hardcoding int or long for function return.

[hosiet]

On the other hand, it may not be necessary to use a custom-defined table_nohash(). The official CPython documentation as written in https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_hash recommends using PyObject_HashNotImplemented directly.