Please help building the cffi recipe

[wexi]

Hi Python-For-Kivy fellows,

Help would be appreciated in building the cffi package, an essential
pyOpenSSL / cryptography dependency.

Thanks, Enoch.

In class CffiRecipe(CompiledComponentsPythonRecipe) I tried the two
python calling options. The original version 11.4.2 fails identically.

1. call_hostpython_via_targetpython = True:

    [DEBUG]:        Finished processing dependencies for cffi==1.11.2
    [INFO]:    Rebuilding compiled components in cffi
    [DEBUG]:   -> running hostpython setup.py clean --all
    [DEBUG]:        running clean
    [DEBUG]:        removing 'build/temp.linux-x86_64-2.7' (and everything under it)
    [DEBUG]:        removing 'build/lib.linux-x86_64-2.7' (and everything under it)
    [DEBUG]:        removing 'build/bdist.linux-x86_64' (and everything under it)
    [DEBUG]:        'build/scripts-2.7' does not exist -- can't clean it
    [DEBUG]:        removing 'build'
    [DEBUG]:   -> running hostpython setup.py build_ext -v
    [DEBUG]:        running build_ext
    [DEBUG]:        failed to import Cython: /home/enoch/.local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so: undefined symbol: PyUnicodeUCS4_DecodeUTF8
    [DEBUG]:        error: Cython does not appear to be installed
   

2. call_hostpython_via_targetpython = False:

    [INFO]:    Building compiled components in cffi
    [INFO]:    -> directory context /home/enoch/.local/share/python-for-android/build/other_builds/libffi/armeabi-v7a/libffi
    [INFO]:    <- directory context /home/enoch/private/gsld
    [INFO]:    -> directory context /home/enoch/.local/share/python-for-android/build/other_builds/cffi-python2/armeabi-v7a/cffi
    [DEBUG]:   -> running hostpython setup.py build_ext -v
    [DEBUG]:        /home/enoch/Android/CrystaX/toolchains/arm-linux-androideabi-5/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/5.3/../../../../arm-linux-androideabi/bin/ld: error: cannot open crtbegin_dynamic.o: No such file or directory
    [DEBUG]:        /home/enoch/Android/CrystaX/toolchains/arm-linux-androideabi-5/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/5.3/../../../../arm-linux-androideabi/bin/ld: error: cannot open crtend_android.o: No such file or directory
    [DEBUG]:        /home/enoch/Android/CrystaX/toolchains/arm-linux-androideabi-5/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/5.3/../../../../arm-linux-androideabi/bin/ld: error: cannot find -lcrystax
    [DEBUG]:        /home/enoch/Android/CrystaX/toolchains/arm-linux-androideabi-5/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/5.3/../../../../arm-linux-androideabi/bin/ld: error: cannot find -lc
    [DEBUG]:        /home/enoch/Android/CrystaX/toolchains/arm-linux-androideabi-5/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/5.3/../../../../arm-linux-androideabi/bin/ld: error: cannot find -ldl
    [DEBUG]:        collect2: error: ld returned 1 exit status
    [DEBUG]:        Note: will not use '__sync_synchronize()' in the C code
    [DEBUG]:        ***** The above error message can be safely ignored.
    [DEBUG]:        
    [DEBUG]:        running build_ext
    [DEBUG]:        building '_cffi_backend' extension
    [DEBUG]:        creating build
    [DEBUG]:        creating build/temp.linux-x86_64-2.7
    [DEBUG]:        creating build/temp.linux-x86_64-2.7/c
    [DEBUG]:        /usr/bin/ccache arm-linux-androideabi-gcc -DANDROID -mandroid -fomit-frame-pointer -D__ANDROID_API__=19 -I/home/enoch/Android/CrystaX/platforms/android-19/arch-arm -isysroot /home/enoch/Android/CrystaX/platforms/android-19/arch-arm -I/home/enoch/.local/share/python-for-android/build/python-installs/gsld/include/python2.7 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DANDROID -mandroid -fomit-frame-pointer -D__ANDROID_API__=19 -I/home/enoch/Android/CrystaX/platforms/android-19/arch-arm -isysroot /home/enoch/Android/CrystaX/platforms/android-19/arch-arm -I/home/enoch/.local/share/python-for-android/build/python-installs/gsld/include/python2.7 -march=armv7-a -mfloat-abi=softfp -mfpu=vfp -mthumb -I/home/enoch/.local/share/python-for-android/build/other_builds/libffi/armeabi-v7a/libffi/arm-unknown-linux-androideabi/include -fPIC -DUSE__THREAD -I/home/enoch/.local/share/python-for-android/build/other_builds/hostpython2/desktop/hostpython2/Include -I/home/enoch/.local/share/python-for-android/build/other_builds/hostpython2/desktop/hostpython2 -c c/_cffi_backend.c -o build/temp.linux-x86_64-2.7/c/_cffi_backend.o
    [DEBUG]:             ^
    [DEBUG]:        c/_cffi_backend.c: In function 'init_cffi_backend':
    [DEBUG]:        c/_cffi_backend.c:7401:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
    [DEBUG]:             Py_INCREF(&MiniBuffer_Type);
    [DEBUG]:             ^
    [DEBUG]:        creating build/lib.linux-x86_64-2.7
    [DEBUG]:        gcc -pthread -shared -DANDROID -mandroid -fomit-frame-pointer -D__ANDROID_API__=19 -I/home/enoch/Android/CrystaX/platforms/android-19/arch-arm -isysroot /home/enoch/Android/CrystaX/platforms/android-19/arch-arm -I/home/enoch/.local/share/python-for-android/build/python-installs/gsld/include/python2.7 -march=armv7-a -mfloat-abi=softfp -mfpu=vfp -mthumb -I/home/enoch/.local/share/python-for-android/build/other_builds/libffi/armeabi-v7a/libffi/arm-unknown-linux-androideabi/include -L/home/enoch/.local/share/python-for-android/build/libs_collections/gsld/armeabi-v7a -DANDROID -mandroid -fomit-frame-pointer -D__ANDROID_API__=19 -I/home/enoch/Android/CrystaX/platforms/android-19/arch-arm -isysroot /home/enoch/Android/CrystaX/platforms/android-19/arch-arm -I/home/enoch/.local/share/python-for-android/build/python-installs/gsld/include/python2.7 -march=armv7-a -mfloat-abi=softfp -mfpu=vfp -mthumb -I/home/enoch/.local/share/python-for-android/build/other_builds/libffi/armeabi-v7a/libffi/arm-unknown-linux-androideabi/include build/temp.linux-x86_64-2.7/c/_cffi_backend.o -lffi -o build/lib.linux-x86_64-2.7/_cffi_backend.so
    [DEBUG]:        gcc: error: unrecognized command line option '-mfpu=vfp'; did you mean '-mcpu='?
    [DEBUG]:        gcc: error: unrecognized command line option '-mthumb'; did you mean '-mtbm'?
    [DEBUG]:        error: command 'gcc' failed with exit status 1
   

[wexi]

This problem with the cffi recipe was solved by defining env['LDSHARED'] to use ARM's gcc.
Should be standard in CompiledComponentsPythonRecipe() just as it is in CppCompiledComponentsPythonRecipe() ... (i.e., should not be a recipe ad hoc fix).
Time for a PR will come when I would finally build the very latest cryptography. No luck yet :-(

[AndreMiras]

Hi @wexi, thanks for reporting, but why closing? This is indeed a bug in CFFI recipe and the bug is still present right?

I came across it and solved in my local recipe a couple of months ago https://github.com/AndreMiras/EtherollApp/blob/v20180531/src/python-for-android/recipes/cffi/__init__.py. So I also created a pull request that solves it and a bunch of other things #1295.

I also think the fix should also be integrated more deeply in recipes parent classes. So feel free to come up with a pull request that also fixes that.

Regarding cryptography, please share your problem I may already have faced and solved it. I would be glad to help, specially if p4a can benefit from it.

[AndreMiras]

 [DEBUG]:        failed to import Cython: /home/enoch/.local/lib/python2.7/site-packages/Cython/Compiler/Scanning.so: undefined symbol: PyUnicodeUCS4_DecodeUTF8

For reference that error can also come from hostpython2 compilation option. The recipe symbols mismatch with system Python. Compiling hostpython2 recipe with --enable-unicode=ucs4 should fix it. See e72d87d#r29869721 comment and also see how I solved it in a custom local recipe https://github.com/AndreMiras/PyWallet/blob/3e7402a/src/python-for-android/recipes/hostpython2/__init__.py#L51