Sagelib build error on Cygwin using system GMP

[embray]

Since #27212 I get an error building sagelib:

[sagelib-8.8.beta3] gcc -shared -Wl,--enable-auto-image-base -L/home/embray/src/sagemath/sage/local/lib -Wl,-rpath,/home/embray/src/sagemath/sage/local/lib -L/home/embray/src/sagemath/sage/local/lib -Wl,-rpath,/home/embray/src/sagemath/sage/local/lib build/temp.cygwin-2.9.0-x86_64-2.7/build/cythonized/sage/ext/fast_callable.o -L/home/embray/src/sagemath/sage/local/lib -L/home/embray/src/sagemath/sage/local/lib/python2.7/config -L/home/embray/src/sagemath/sage/local/lib -lpython2.7 -o build/lib.cygwin-2.9.0-x86_64-2.7/sage/ext/fast_callable.dll
[sagelib-8.8.beta3] build/cythonized/sage/data_structures/bounded_integer_sequences.c:3442:29: error: conflicting types for ‘__pyx_f_4sage_15data_structures_25bounded_integer_sequences_limb_one_set_bit’
[sagelib-8.8.beta3]  static CYTHON_INLINE mp_limb_t __pyx_f_4sage_15data_structures_25bounded_integer_sequences_limb_one_set_bit(mp_bitcnt_t __pyx_v_n) {
[sagelib-8.8.beta3]                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[sagelib-8.8.beta3] build/cythonized/sage/data_structures/bounded_integer_sequences.c:3170:29: note: previous declaration of ‘__pyx_f_4sage_15data_structures_25bounded_integer_sequences_limb_one_set_bit’ was here
[sagelib-8.8.beta3]  static CYTHON_INLINE mp_limb_t __pyx_f_4sage_15data_structures_25bounded_integer_sequences_limb_one_set_bit(mp_bitcnt_t); /*proto*/
[sagelib-8.8.beta3]                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

followed by a long string of similar errors in the same module.

This is probably similar to the error fixed in #27713 but a different manifestation thereof.

This is partially fixed by the PR linked below, but then another related error arises related to flint and/or zn_poly abusing GMP type definitions:

[sagelib-8.8.beta3] g++ -shared -Wl,--enable-auto-image-base -L/home/embray/src/sagemath/sage/local/lib -Wl,-rpath,/home/embray/src/sagemath/sage/local/lib -L/home/embray/src/sagemath/sage/local/lib -Wl,-rpath,/home/embray/src/sagemath/sage/local/lib build/temp.cygwin-2.9.0-x86_64-2.7/build/cythonized/sage/rings/polynomial/polynomial_zz_pex.o -L/home/embray/src/sagemath/sage/local/lib -L/home/embray/src/sagemath/sage/local/lib/python2.7/config -L/home/embray/src/sagemath/sage/local/lib -lntl -lgmp -lstdc++ -lpython2.7 -o build/lib.cygwin-2.9.0-x86_64-2.7/sage/rings/polynomial/polynomial_zz_pex.dll -lpari
[sagelib-8.8.beta3] [380/437] gcc -I/usr/include/ncurses -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wno-unused -I./sage/cpython -I./sage/libs/ntl -I/home/embray/src/sagemath/sage/local/lib/python2.7/site-packages/cysignals -I/home/embray/src/sagemath/sage/local/include -I/home/embray/src/sagemath/sage/src -I/home/embray/src/sagemath/sage/src/sage/ext -I/home/embray/src/sagemath/sage/local/include/python2.7 -I/home/embray/src/sagemath/sage/local/lib/python2.7/site-packages/numpy/core/include -Ibuild/cythonized -I/home/embray/src/sagemath/sage/local/include/python2.7 -c build/cythonized/sage/rings/polynomial/polynomial_zmod_flint.cpp -o build/temp.cygwin-2.9.0-x86_64-2.7/build/cythonized/sage/rings/polynomial/polynomial_zmod_flint.o -fno-strict-aliasing -DCYTHON_CLINE_IN_TRACEBACK=1 -std=gnu++11
[sagelib-8.8.beta3] In file included from build/cythonized/sage/rings/polynomial/polynomial_zmod_flint.cpp:697:0:
[sagelib-8.8.beta3] ../local/include/zn_poly/zn_poly.h:72:23: error: conflicting declaration ‘typedef long unsigned int mp_limb_t’
[sagelib-8.8.beta3]  typedef unsigned long  ulong;
[sagelib-8.8.beta3]                        ^~~~~~~
[sagelib-8.8.beta3] In file included from build/cythonized/sage/rings/polynomial/polynomial_zmod_flint.cpp:676:0:
[sagelib-8.8.beta3] /usr/include/gmp.h:138:32: note: previous declaration as ‘typedef long long unsigned int mp_limb_t’
[sagelib-8.8.beta3]  typedef unsigned long long int mp_limb_t;
...

and followed by some other errors that look related.

Upstream PR: flintlib/flint#557

Upstream: Fixed upstream, but not in a stable release.

CC: @jdemeyer

Component: porting: Cygwin

Keywords: cygwin sagelib gmp flint

Issue created by migration from https://trac.sagemath.org/ticket/27714

[embray]

comment:2

Hmm, changing these ctypedefs to what I actually have in my gmp.h does not seem to fix it. If my reading of the Cython docs is correct this actually should't matter anyways: It's still going to output literally mp_limb_t to the C code and does not redefine it in any way.

The "conflicting types" error first appears just after

/* Late includes */
#include "macros.h"
#include "string_impl.h"
#include "flint/flint.h"
#include "flint/fmpz.h"
#include "cython_metaclass.h"

so I wonder if one of these is somehow responsible.

[embray]

Changed keywords from cygwin sagelib gmp to cygwin sagelib gmp flint

[embray]

comment:3

I traced the problem to this line in flint.h:

#define mp_bitcnt_t ulong

I have no idea why it would do this, but it's almost certainly wrong.

[embray]

comment:4

Added 10 years ago for no readily apparent reason in flintlib/flint@f988d3e

Later it was changed to #define mp_bitcnt_t ulong in a mass rename. But flint's ulong type is defined in terms of mp_limb_t hence the breakage.

[embray]

Upstream: Reported upstream. No feedback yet.

[embray]

Changed upstream from Reported upstream. No feedback yet. to Fixed upstream, but not in a stable release.

[embray]

comment:8

The previous PR to flint partially fixed the problem, but not fully. See updated description.

[embray]

comment:9

Yeah, zn_poly has its own typedef unsigned long ulong totally unrelated to flint, except when both headers get included in the same module it's a mess. I'll clean up the zn_poly ulong stuff... :(

[embray]

comment:10

Wow. PARI has one of these too. In pari/parigen.h:

#ifdef _WIN64
typedef unsigned long long pari_ulong;
#define long long long
#define labs llabs
#else
typedef unsigned long pari_ulong;
#endif
#define ulong pari_ulong
typedef long *GEN;

I think I encountered a problem caused by this #define long long long before. I hate it.

[embray]

comment:11

I think ultimately the worse perpetrator of this is flint. Its ulong and slong defines result in the worse compatibility issues.

[embray]

comment:12

This will be fixed by #27721 if it's accepted.

[embray]

comment:13

Moving open critical and blocker issues to the next release milestone (optimistically).

[embray]

comment:14

Should be fixed by #27721.