libobs-metal fails to configure when ENABLE_PLUGINS=OFF

[glikely]

Operating System Info

macOS 15

Other OS

No response

OBS Studio Version

32.1.2

OBS Studio Version (Other)

No response

OBS Studio Log URL

Build failure

OBS Studio Crash Log URL

No response

Expected Behavior

Expected build would have the following output. To get the following I had to deleting the libobs-metal line from CMakeLists.txt

% cmake -B build_macos --preset macos -DENABLE_PLUGINS:BOOL=OFF
-- Checking for interprocedural optimization support
-- Checking for interprocedural optimization support - enabled [Release, MinSizeRel]
-- Setting up Pre-Built obs-deps (universal)
-- Setting up Pre-Built obs-deps (universal) - done
-- Setting up Pre-Built Qt6 (universal)
-- Setting up Pre-Built Qt6 (universal) - done
-- Setting up Chromium Embedded Framework (arm64)
-- Setting up Chromium Embedded Framework (arm64) - skipped
                      _                   _             _ _
                 ___ | |__  ___       ___| |_ _   _  __| (_) ___
                / _ \| '_ \/ __|_____/ __| __| | | |/ _` | |/ _ \
               | (_) | |_) \__ \_____\__ \ |_| |_| | (_| | | (_) |
                \___/|_.__/|___/     |___/\__|\__,_|\__,_|_|\___/

OBS:  Application Version: 32.1.2-modified - Build Number: 47
==================================================================================


------------------------       Enabled Features           ------------------------
 - OpenGL renderer
------------------------       Disabled Features          ------------------------
 - Plugin Support
 - User Interface
----------------------------------------------------------------------------------
-- Configuring done (0.7s)
-- Generating done (0.0s)
-- Build files have been written to: /Users/grant/hacking/obs-studio/build_macos

Current Behavior

The following build command results in a failure at the configure step:

% cmake -B build_macos --preset macos -DENABLE_PLUGINS:BOOL=OFF
-- Checking for interprocedural optimization support
-- Checking for interprocedural optimization support - enabled [Release, MinSizeRel]
-- Setting up Pre-Built obs-deps (universal)
-- Setting up Pre-Built obs-deps (universal) - done
-- Setting up Pre-Built Qt6 (universal)
-- Setting up Pre-Built Qt6 (universal) - done
-- Setting up Chromium Embedded Framework (arm64)
-- Setting up Chromium Embedded Framework (arm64) - skipped
                      _                   _             _ _
                 ___ | |__  ___       ___| |_ _   _  __| (_) ___
                / _ \| '_ \/ __|_____/ __| __| | | |/ _` | |/ _ \
               | (_) | |_) \__ \_____\__ \ |_| |_| | (_| | | (_) |
                \___/|_.__/|___/     |___/\__|\__,_|\__,_|_|\___/

OBS:  Application Version: 32.1.2-modified - Build Number: 48
==================================================================================


------------------------       Enabled Features           ------------------------
 - Metal renderer
 - OpenGL renderer
------------------------       Disabled Features          ------------------------
 - Plugin Support
 - User Interface
----------------------------------------------------------------------------------
-- Configuring done (0.7s)
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
CMake Error: CMake can not determine linker language for target: libobs-metal
-- Generating done (0.0s)
CMake Generate step failed.  Build files cannot be regenerated correctly.

Steps to Reproduce

1. Clone the latest obs studio on MacOS 15.
2. Configure with cmake -DENABLE_PLUGINS:BOOL=OFF

I first found this behaviour with version 32.0.0. Git bisect narrows the commit down to 32.0.0-beta1-34-gd8b19c3c2, "libobs-metal: Add Metal renderer"

Anything else we should know?

Another hacky to fix is to make mac-virtualcam in plugins/CMakeLists.txt unconditional. It looks like mac-virtualcam adds something that libobs-metal needs. I'm still investigating.

[jcm93]

Would be resolved by #13250

[glikely]

After searching through the configure code, and looking at plugins/mac-virtualcam/src/camera-extension/CMakeLists.txt, it looks like libobs-metal/CMakeLists.txt is missing enable_language(Swift). Adding that to the top of the file solves the configure failure.

[glikely]

Would be resolved by #13250

Ah, thanks. I had looked for an open PR or issue about this but didn't find one. Glad to see it is in flight.

[danrossi]

The error and requirement for the swift language is visible with this plugin template with updated spec versions. It configures the source archive. https://github.com/danrossi/obs-plugintemplate/tree/update-spec

CMake Error: CMake can not determine linker language for target: libobs-metal

[danrossi]

Tough gig. But I have figured out a patch until this fix makes it into the source archive.

https://github.com/danrossi/obs-plugintemplate/blob/update-spec/cmake/common/buildspec_common.cmake#L71