CURL fails to build on macOS 10.15.2 about hunter

[rbsheth]

Hmm, I've also been building CURL on macOS 10.15 successfully. I'll try reproducing this when I update my Mac.

[jothepro]

Update: I tried to build CURL from submodule to investigate the issue:

hunter_config(CURL GIT_SUBMODULE "thirdparty/curl")

In the given folder I cloned the hunterized curl repository, which should be exactly the same code that is checked out by hunter.
This now builds successfully. The CURL version is the same (7.60.0-DEV)

As I remove the reference to the submodule and let hunter pull the sources, the build fails again.
Maybe this is some kind of a weird caching issue? I deleted .hunter in the user-dir multiple times, doesn't help. Am I missing some cache that might be screwed up?

[rbsheth]

Interesting. Do you have remote cache download enabled? If so, try disabling that.

[jothepro]

Actually I'm not sure. I think it is not enabled by default, is it?
Right now I have a strong feeling that something else is fundamentally wrong with my project setup. Even with the described workaround I need to configure curl in the project that I posted for reproduction, because it still fails to build in my original project. Once a successful build is in the local cache, I can use it from my original project. Im confused and will definitely have to dig deeper into the issues linked in here once I find time for that.

[Bjoe]

@jothepro I'm not 100% sure but I think you run in the same issue like #147

I saw that you are using
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang as compiler. Try to use /usr/bin/clang as compiler.
There are the "same" compiler and they are using the same toolchain path ... see my output:

iMac:~ joergboehme$ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang --version
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin18.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
iMac:~ joergboehme$ /usr/bin/clang --version
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin18.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

but there is "something" different!

I absolutely don't know what are different but I tried with other "opensource" projects and it works with /usr/bin/clang and not with /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang ....
Maybe somebody can tell me what are the different between /usr/bin/clang and /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang ... would be nice to know :-)

[Bjoe]

@jothepro I found your problem ....

As workaround:
Remove in your CMakeList.txt line11 LANGUAGES CXX and remove your hunter build id (.hunter/_Base/<Hunter-ID>/), then it works ....

Why?
Here in detail:

If you set in project cmake command the LANGUAGES then only the specified language compiler is verified via cmake. In your example it was only the C++ compiler.
At the end, hunter is verified if the ABI was correct detected via cmake. CMAKE_CXX_ABI_COMPILED is an undocumented property from cmake and is set when you get following output:

...
-- Detecting CXX compiler ABI info - done
...

This means, in your example, the C compiler is not verified and CMAKE_C_ABI_COMPILED is set as empty value.

To build third-party libs in hunter faster, hunter is save this result in the "cache" file (see in your .hunter/_Base/<Hunter-ID>/<Toolchain-ID>/<Config-id>/cache.cmake).
This means in the curl project, where the C compiler is enabled and CMAKE_C_ABI_COMPILED is set via the cache file and cmake is not execute the ABI detection then in hunter the verification is failing

In my opinion, we should not save any "cmake environment" when it is not successful!
My idea is to add an if statement in hunter_create_cache_file line 110 like:

if(CMAKE_${lang}_ABI_COMPILED)
  hunter_status_debug("ABI forwarding: CMAKE_${lang}_ABI_COMPILED = ${CMAKE_${lang}_ABI_COMPILED}")
    file(
        APPEND
        "${temp_path}"
        "set(CMAKE_${lang}_ABI_COMPILED \"${CMAKE_${lang}_ABI_COMPILED}\" CACHE INTERNAL \"\")\n"
    )
endif()

@rbsheth and @bkotzz what do you think ?

[Bjoe]

or maybe we remove this DEFINED from hunter_create_cache_file line 70

[jothepro]

@Bjoe wow thanks for your in-depth explanations! I also figured out after a while that my LANGUAGES definition was the real problem. Not caching the "corrupted" state would have helped me to find the real issue faster I think, so I'd appreciate these changes. ☺️

[jothepro]

@rbsheth @bkotzz What do you think of the changes that @Bjoe proposes? Otherwise I guess I will close this issue, the original problem is solved for me.

[rbsheth]

I'd be okay with @Bjoe's suggestion provided that it doesn't slow down builds considerably.

[Bjoe]

Ok let me do this... hopefully I will find a "time slot" ....