Will not compile on OX X 10.14

[hyanwong]

when doing pip3 install mplcairo on the new version of OS X (Mojave) I get:

    src/_mplcairo.cpp:42:3: error: call to unavailable function 'visit': introduced in macOS 10.14
      std::visit([&](auto const& aa) -> void {
      ^~~~~~~~~~
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/variant:1524:26: note: candidate function [with _Visitor = (lambda at src/_mplcairo.cpp:42:14), _Vs = <const std::__1::variant<_cairo_antialias, bool> &>] has been explicitly made unavailable
    constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
                             ^

[anntzer]

From the error message, it looks like you are using Xcode's llvm? You need to install a newer version with homebrew or anaconda, see https://github.com/anntzer/mplcairo#osx.

[hyanwong]

You are right. Thanks. I guess this can be closed then? Slightly annoying that the latest OS X version doesn't work out of the box (not your fault though!)

[anntzer]

Actually looking at this again perhaps it can be solved by changing the -mmacosx-version-min flag (twice) in https://github.com/anntzer/mplcairo/blob/master/setup.py#L151? However I worry this will cause breakage on earlier OSX versions...

[hyanwong]

Hmm, thanks a lot for looking. I guess you want to avoid maintaining version-specific code here? It would be nice not to have to install a separate llvm for more recent OS versions. Let me know if you want me to try compiling with a different setup.py (lines 151 & 158) on the latest 10.14?

[hyanwong]

FWIW, I can confirm that this compiles on 10.14 if I set "-mmacosx-version-min=10.14" in both places, but will not if I set ""-mmacosx-version-min=10.13".

[anntzer]

I can live with version specific code if it helps, and here it definitely makes sense.
In practice I'll likely wait a bit until Azure CI update their images to 10.14 so that I can test (I don't have access to an OSX machine myself)...
If you are willing to help with this (that would be very appreciated): if you build a wheel on 10.14 (python setup.py bdist_wheel, perhaps followed with a call to https://pypi.org/project/delocate/ (not clear if it's actually needed)), can you try if that wheel works on a "naive" 10.14 machine (say, with no xcode, no custom llvm, no nothing?) In other words, can I distribute a mplcairo-0.1-cp37-macosx_10_14_intel.whl with the expectation that it'll work on any 10.14 machine?

[hyanwong]

Apologies for the slow reply. I don't know much about wheel building etc, and I'm not sure how (or whether I want to) remove e.g. the command line developer tools I've installed. Perhaps better to wait until there are 10.14 images on Azure CI.

Also, it's not clear here if you want me to do this with the original "-mmacosx-version-min=10.9"?

[anntzer]

No, I was hoping that you try without the -mmacosx-version-min=10.9.
In any case no worries, it's good that the fix that works for you, and I'll wait for availability of 10.14 on Azure to move forward.
I'll leave this open as a self-reminder for now.

[anntzer]

I decided to just push that patch in 152d821. Feel free to let me know if you find any additional issues.