parallelstl: install CMake config files

[omor1]

Checklist

• ran brew update and can still reproduce the problem?
• ran brew doctor, fixed all issues and can still reproduce the problem?
• ran brew gist-logs <formula> (where <formula> is the name of the formula that failed) and included the output link?
• if brew gist-logs didn't work: ran brew config and brew doctor and included their output with your issue?

What you were trying to do (and why)

The parallelstl formula doesn't use CMake to generate and install the ParallelSTLConfig.cmake file. This makes using the Parallel STL library more difficult than it ought to be.

What happened (include command output)

Parallel STL is missing the CMake config file after installation via brew.

What you expected to happen

Installing Parallel STL would fully install Parallel STL.

[omor1]

brew doctor tells me that the command line tools are supposedly out-of-date; System Preferences does not show me an update. This prevents me from running brew gist-logs. In any case, this is very obviously a problem with the formula, given that it doesn't generate a bottle.

[Bo98]

Should be fixed now.

[omor1]

You forgot to bump the revision!

[Bo98]

Indeed - I'll go bump it. You can do brew reinstall parallelstl in the meantime.

[omor1]

I've already done that :). Thanks!

[omor1]

Using pstl::ParallelSTL from CMake seems to be problematic in the current setup. The replacement STL headers are installed in the non-standard stdlib directory inside the parallelstl Cellar directory, but this isn't linked into /usr/local/stdlib. It seems that ParallelSTLTargets.cmake finds the install directory based on ${CMAKE_CURRENT_LIST_FILE}, which I guess doesn't resolve the symbolic link to the Cellar directory, so it tries to find stdlib in /usr/local rather than in /usr/local/Cellar/parallelstl/20200330.

I'm not sure what the solution here is. Installing the stdlib directory is inelegant, but should work.

[Bo98]

Upstream's CMake files don't even install stdlib by default. I had to do that bit manually. And since it isn't in a standard Unix location - it doesn't get symlinked to /usr/local. (You can find it in /usr/local/opt/parallelstl/stdlib, but that probably doesn't help you.) There is strict enforcements on what gets symlinked to /usr/local.

I think the solution would be for it to be in a standard location, such as include/parallelstl/stdlib or maybe even something in share. I suspect upstream don't give that flexibility though.

[omor1]

I'm as flummoxed as you are. The separation of the replacement STL files into stdlib only happened with the last two releases. Maybe installing it into /usr/local/Cellar/parallelstl/<version>/include/pstl/stdlib? That would likely require a patch to CMakeLists to change the include directory INSTALL_INTERFACE. Mostly it seems that upstream is problematic for this.

[Bo98]

I could mess around with patching the CMakeLists but I'd like it to not be something that sticks around forever. It would be worth making a bug report upstream first and see if there's any initial thoughts there.

[omor1]

I'm working on that right now.

[omor1]

For now I'm working around this by using -DParallelSTL_ROOT=/usr/local/opt/parallelstl when configuring CMake.

[omor1]

In the meantime, should we open this issue back up?

[Bo98]

We generally don't for upstream issues but I'll still be receiving notifications for this issue and may re-open when there's action to be done on our side.

If you need any further evidence for upstream, vcpkg were also forced to have to patch upstream's scripts to actually install stdlib and to do so in a standard location include/pstl: https://github.com/microsoft/vcpkg/blob/020923a98dac40b55098170ae3dcb65a4eab58b5/ports/parallelstl/fix-cmakelist.patch

[omor1]

That's a good catch, I'll make note of it on oneapi-src/oneDPL#33.

[Bo98]

Yeah, it's good to have other package managers to compare to - I didn't want them to get all caught up in the Homebrew symlink stuff.

I'm pretty sure Debian (if they were to have parallelstl) would also reject anything that expected things in /usr/local outside of standard locations, and would also likely raise a bug report if the install script didn't actually install everything.