On Mac, target macOS 10.9 when possible (fixes build on XCode 10+)

[JoshRosen]

This patch aims to fix an issue where python-sasl cannot be compiled with newer versions of XCode. In particular, this library fails to compile out-of-the-box on OS X Mojave (see cloudera/thrift_sasl#15).

The problem seems to be related to missing stdlibc++ headers, which are not installed by default in XCode 10+.

To fix this issue, I copied changes from pandas-dev/pandas#24274 (with proper attribution). Quoting from that patch description:

For extension builds, distutils targets the same macOS version as python was built for, even if the host system is newer. This can cause problems when building on a 10.9+ system, with a python built for <10.9. Targetting macOS <10.9 sets the c++ standard library to stdlibc++, which was deprecated in 10.9 in favour of libc++. Starting with Xcode 10, stdlibc++ is no longer installed by default, so isn't guaranteed to be available. This can be an issue with the current 64/32b universal builds of python, which target macOS 10.7.

Another reason to do this is to move over to 10.9 / libc++ where possible, as the current 64-bit builds of python have done.

This worked for me and I think it's a simpler approach than some of the other workarounds suggested in cloudera/thrift_sasl#15 and hkwi/python-geohash#27 because it doesn't require the installation of additional headers or commandline tools. I have little experience with native code builds, however, so please chime in if I'm overlooking something.

[wesm]

This looks OK to me. Who is maintaining this now and can make a release, @timarmstrong @toddlipcon?

[timarmstrong]

I think @lekv was investigating a release.

[lekv]

Yes, I'm planning to put together a new release in the next days. I'm still figuring out the process and probably will put up a RC beforehand so everyone can have a look at it.

[jrkinley-zz]

I've just hit this issue. Is there an RC available @lekv?

[lekv]

We've just released version 0.15.0 and it's available on pypi.

[JoshRosen]

HI @lekv,

Could you point me to the PyPI listing page for the 0.15.0 release of sasl?

From https://pypi.org/project/sasl/ it looks like there hasn't been a new release. Are you sure you were referring to this library and not a different one in your comment? Edit: looks like you were referring to an Impyla release, not this library.

I'm bumping this because it sounds like this is still a problem for thrift_sasl users, some of whom are resorting to installing from my branch rather than an official PyPI release: cloudera/thrift_sasl#15 (comment)

[jrkinley-zz]

Hi @lekv, I'm still having to install from @JoshRosen's branch. Please can we get an official fix on pypi?

[lekv]

I confused this one with impyla. However, pip install sasl works for me on Mojave in a fresh venv with both python2 and python3 and outside of a venv. How are you trying to install it?

[Tagar]

https://pypi.org/project/sasl3/
incorporates this PR

[VincentBLortie]

@lekv pip install sasl in a fresh venv running Python 3.7.0, on MacOS 10.14.6 gives me:

    warning: include path for stdlibc++ headers not found; pass '-stdlib=libc++' on the command line to use the libc++ standard library instead [-Wstdlibcxx-not-found]
    sasl/saslwrapper.cpp:249:10: fatal error: 'string' file not found
    #include <string>
             ^~~~~~~~
    1 warning and 1 error generated.
    error: command 'gcc' failed with exit status 1

sasl3 on PyPI does seem to fix the problem, but thrift_sasl's dependency is on this package.

[lekv]

Thanks @VincentBLortie for posting the error. From [https://github.com/pandas-dev/pandas/issues/23424#issuecomment-446393981|pandas/issues/23424#issuecomment-446393981] it looks to me like some older library versions on my system have made this work.

It may work for some users, for 1 of 2 reasons:

• libstdc++ is lying around somewhere from a previous Xcode 9 install
• when running a recent 64-bit only variant of python, which targets macOS 10.9 and hence libc++

With that understanding the change looks good to me (I validated that it can be installed from with this PR on my local machine).