Build failure on macOS 10.15

[gnachman]

There's a signed/unsigned comparison that causes a warning, and warnings are errors.

The user can't hack around it by setting CFLAGS because setup.py has:

if sys.platform.startswith('darwin'):
    macos_sdk_path = subprocess.check_output(['xcrun', '--show-sdk-path']).decode().strip()
    os.environ['CFLAGS'] = '-isysroot "%s" -framework IOKit -framework CoreFoundation' % macos_sdk_path
    os.environ['LDFLAGS'] = ''

This is sad because it keeps people from using an analog bell for their terminals: gnachman/iTerm2#428

I suppose fixing hid.c is hard, but doing disgusting things with CFLAGS is easy :)

The error is:

$ python3 setup.py install
WARNING: The wheel package is not available.
running install
running bdist_egg
running egg_info
writing hidapi.egg-info/PKG-INFO
writing dependency_links to hidapi.egg-info/dependency_links.txt
writing requirements to hidapi.egg-info/requires.txt
writing top-level names to hidapi.egg-info/top_level.txt
reading manifest file 'hidapi.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'hidapi.egg-info/SOURCES.txt'
installing library code to build/bdist.macosx-10.12-x86_64/egg
running install_lib
running build_ext
cythoning hid.pyx to hid.c
/Users/gnachman/Downloads/hidapi-0.9.0.post3/.eggs/Cython-0.29.21-py3.7-macosx-10.12-x86_64.egg/Cython/Compiler/Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /Users/gnachman/Downloads/hidapi-0.9.0.post3/hid.pyx
  tree = Parsing.p_module(s, pxd, full_module_name)
building 'hid' extension
creating build
creating build/temp.macosx-10.12-x86_64-3.7
creating build/temp.macosx-10.12-x86_64-3.7/hidapi
creating build/temp.macosx-10.12-x86_64-3.7/hidapi/mac
clang -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -mmacosx-version-min=10.12 -mmacosx-version-min=10.12 -mmacosx-version-min=10.12 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -framework IOKit -framework CoreFoundation -Ihidapi/hidapi -I/Users/gnachman/Library/ApplicationSupport/iTerm2/Scripts/ding/iterm2env/versions/3.7.5/include/python3.7m -c hid.c -o build/temp.macosx-10.12-x86_64-3.7/hid.o
clang: warning: -framework IOKit: 'linker' input unused [-Wunused-command-line-argument]
clang: warning: -framework CoreFoundation: 'linker' input unused [-Wunused-command-line-argument]
clang -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -mmacosx-version-min=10.12 -mmacosx-version-min=10.12 -mmacosx-version-min=10.12 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -framework IOKit -framework CoreFoundation -Ihidapi/hidapi -I/Users/gnachman/Library/ApplicationSupport/iTerm2/Scripts/ding/iterm2env/versions/3.7.5/include/python3.7m -c hidapi/mac/hid.c -o build/temp.macosx-10.12-x86_64-3.7/hidapi/mac/hid.o
clang: warning: -framework IOKit: 'linker' input unused [-Wunused-command-line-argument]
clang: warning: -framework CoreFoundation: 'linker' input unused [-Wunused-command-line-argument]
hidapi/mac/hid.c:267:20: warning: comparison of integers of different signs: 'CFIndex' (aka 'long') and 'size_t' (aka 'unsigned long') [-Wsign-compare]
                if (chars_copied == len)
                    ~~~~~~~~~~~~ ^  ~~~
1 warning generated.
creating build/lib.macosx-10.12-x86_64-3.7
clang -bundle -undefined dynamic_lookup -L/Users/gnachman/Library/Application Support/iTerm2/iterm2env-67/versions/3.7.5/readline/lib -L/Users/gnachman/Library/Application Support/iTerm2/iterm2env-67/versions/3.7.5/lib -L/Users/gnachman/Library/Application Support/iTerm2/iterm2env-67/versions/3.7.5/readline/lib -L/Users/gnachman/Library/Application Support/iTerm2/iterm2env-67/versions/3.7.5/lib -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -framework IOKit -framework CoreFoundation build/temp.macosx-10.12-x86_64-3.7/hid.o build/temp.macosx-10.12-x86_64-3.7/hidapi/mac/hid.o -o build/lib.macosx-10.12-x86_64-3.7/hid.cpython-37m-darwin.so
clang: error: no such file or directory: 'Support/iTerm2/iterm2env-67/versions/3.7.5/readline/lib'
clang: error: no such file or directory: 'Support/iTerm2/iterm2env-67/versions/3.7.5/lib'
clang: error: no such file or directory: 'Support/iTerm2/iterm2env-67/versions/3.7.5/readline/lib'
clang: error: no such file or directory: 'Support/iTerm2/iterm2env-67/versions/3.7.5/lib'
error: command 'clang' failed with exit status 1

[prusnak]

This is an upstream bug in hidapi. Can you please open an issue here? https://github.com/libusb/hidapi

[todbot]

I don't think it's an upstream bug in hidapi, it looks more like you don't have readline installed. What happens if you do brew install readline and try it again?

[gnachman]

FYI this was fixed upstream in libusb/hidapi#198

[prusnak]

I bumped hidapi submodule to master in d824d96

Can you please test if that fixes your issue? @gnachman

[gnachman]

Builds and loads great. I am not actually the end user, so I can't test the functionality. But considering the fix, I'm content to leave it closed. Thank you for your help.