Build Failure: RuntimeError: context has already been set in multiprocessing on Python 3.14

[darky7669]

Plaintext
File "/home/darky/.cache/yay/openage-git/src/build/openage/main.py", line 178, in
multiprocessing.set_start_method('spawn')
File "/usr/lib/python3.14/multiprocessing/context.py", line 247, in set_start_method
raise RuntimeError('context has already been set')
RuntimeError: context has already been set
System Info
OS: Cachy OS

Python Version: 3.14.3

Compiler: GCC 15.2.1

Openage Version: 0.6.0.r197.g865bd548d-1

Technical Summary for Devs
It appears that in Python 3.14, the multiprocessing context is being initialized earlier than in previous versions. When openage/main.py calls set_start_method('spawn'), it triggers a RuntimeError because the method is not being called with force=True. This prevents the codegen_run from completing, which causes the CMake configuration to fail.

[darky7669]

You said

:: Proceed with install? [Y/n] y

==> Making package: openage-git 0.6.0.r37.gbeb894520-2 (Jo 05 mar 2026 17:46:10 +0200)

==> Retrieving sources...

-> Cloning openage git repo...

Cloning into bare repository '/home/darky/.cache/yay/openage-git/openage'...

remote: Enumerating objects: 112055, done.

remote: Counting objects: 100% (1853/1853), done.

remote: Compressing objects: 100% (450/450), done.

remote: Total 112055 (delta 1651), reused 1403 (delta 1403), pack-reused 110202 (from 4)

Receiving objects: 100% (112055/112055), 155.03 MiB | 36.51 MiB/s, done.

Resolving deltas: 100% (82643/82643), done.

==> WARNING: Skipping verification of source file PGP signatures.

==> Validating source files with sha256sums...

openage ... Skipped

:: (1/1) Parsing SRCINFO: openage-git

==> Making package: openage-git 0.6.0.r37.gbeb894520-2 (Jo 05 mar 2026 17:46:20 +0200)

==> Checking runtime dependencies...

==> Checking buildtime dependencies...

==> Retrieving sources...

-> Updating openage git repo...

==> Validating source files with sha256sums...

openage ... Skipped

==> Removing existing $srcdir/ directory...

==> Extracting sources...

-> Creating working copy of openage git repo...

Cloning into 'openage'...

done.

==> Starting pkgver()...

==> Updated version: openage-git 0.6.0.r197.g865bd548d-1

==> Sources are ready.

==> Making package: openage-git 0.6.0.r197.g865bd548d-1 (Jo 05 mar 2026 17:46:26 +0200)

==> Checking runtime dependencies...

==> Checking buildtime dependencies...

==> WARNING: Using existing $srcdir/ tree

==> Starting pkgver()...

==> Starting build()...





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| _)/ _____|_______|_______|_ |

| | ( (____ _____ _ | | ___ ____ _____ ____ _____ ____ _____

| | \____ \| ___) | | | | / _ \| _ \| ___ | _ \(____ |/ _ | ___ |

| |_ _____) ) | | | _| | | |_| | |_| | ____| | | / ___ ( (_| | ____|

|___|______/|_| |_| (___| \___/| __/|_____)_| |_\_____|\___ |_____)

|_| (_____|



Welcome to the SFT technologies computer-aided openage build system!



You have chosen, or been chosen, to attempt the daring task of building openage.

If you have installed all the dependencies that are conveniently listed in

[doc/building.md], this _might_ just work!



If it doesn't, consider reporting the issue, or ask for help:

* GitHub: https://github.com/SFTtech/openage

* Matrix: #sfttech:matrix.org



-- The CXX compiler identification is GNU 15.2.1

-- Detecting CXX compiler ABI info

-- Detecting CXX compiler ABI info - done

-- Check for working CXX compiler: /usr/bin/c++ - skipped

-- Detecting CXX compile features

-- Detecting CXX compile features - done

-- Performing Test HAVE_REQUIRED_CXX20_SUPPORT

-- Performing Test HAVE_REQUIRED_CXX20_SUPPORT - Success

-- Found Python3: /usr/bin/python3.14 (found suitable exact version "3.14.3") found components: Interpreter Development NumPy Development.Module Development.Embed

-- Found Python: /usr/bin/python3.14 (Required is at least version "3.9")

-- Found Cython: /usr/bin/python3.14 -m cython (found suitable version "3.2.4", minimum required is "3.0.10")

PYTHON_LIBRARIES: /usr/lib/libpython3.14.so

-- Checking python3 module PIL.Image - Success

-- Checking python3 module PIL.ImageDraw - Success

-- Checking python3 module numpy - Success

-- Checking python3 module pygments - Success

-- Checking python3 module mako.template - Success

-- Checking python3 module toml - Success

-- Checking python3 module lz4 - Success

-- Set PROJECT_VERSION from git.

-- Found Doxygen: /usr/bin/doxygen (found version "1.16.1") found components: doxygen missing components: dot

CMake Warning at buildsystem/doxygen.cmake:17 (message):

graphviz dot couldn't be found, you won't have cool graphs in the docs.

Call Stack (most recent call first):

buildsystem/doxygen.cmake:54 (doxygen_init)

CMakeLists.txt:190 (include)





-- The C compiler identification is GNU 15.2.1

-- Detecting C compiler ABI info

-- Detecting C compiler ABI info - done

-- Check for working C compiler: /usr/bin/cc - skipped

-- Detecting C compile features

-- Detecting C compile features - done

-- Found Freetype: /usr/lib/libfreetype.so (found version "2.14.1")

-- Found ZLIB: /usr/lib/libz.so (found version "1.3.1")

-- Found PNG: /usr/lib/libpng.so (found version "1.6.55")

-- Found Opusfile: /usr/lib/libopusfile.so

-- Found Epoxy: /usr/lib/libepoxy.so

-- Found HarfBuzz: /usr/lib/libharfbuzz.so (found suitable version "12.3.2", minimum required is "1.0.0")

-- Performing Test CMAKE_HAVE_LIBC_PTHREAD

-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success

-- Found Threads: TRUE

-- Performing Test HAVE_STDATOMIC

-- Performing Test HAVE_STDATOMIC - Success

-- Found WrapAtomic: TRUE

-- Found OpenGL: /usr/lib/libOpenGL.so

-- Found WrapOpenGL: TRUE

-- Found WrapVulkanHeaders: /usr/include

-- Could NOT find GCCBacktrace (missing: GCCBacktrace_LIBRARIES GCCBacktrace_INCLUDE_DIRS)

-- optional dependency is unavailable: backtrace

-- Found GPerfTools: /lib/libtcmalloc_and_profiler.so

-- Found Inotify: /usr/include

-- Looking for wsyncup in /usr/lib/libcurses.so

-- Looking for wsyncup in /usr/lib/libcurses.so - found

-- Found Curses: /usr/lib/libncursesw.so

-- Found Vulkan: /lib/libvulkan.so (found version "1.4.341") found components: glslc glslangValidator



cython module

run [embedded interpreter] [noinstall]

openage.cython_check

openage.cabextract.lzxd

openage.cabextract.cabchecksum

openage.convert.processor.export.terrain_merge

openage.convert.processor.export.texture_merge

openage.convert.service.export.interface.visgrep

-- Found Ogg: /usr/lib/libogg.so

openage.convert.service.export.opus.opusenc

openage.convert.service.export.png.binpack

openage.convert.service.export.png.png_create

openage.convert.value_object.read.media.sld

openage.convert.value_object.read.media.slp

openage.convert.value_object.read.media.smp

openage.convert.value_object.read.media.smx

openage.cppinterface.exctranslate

openage.cppinterface.exctranslate_tests

openage.cppinterface.pyobject

openage.cppinterface.setup_checker

openage.cvar.cvar

openage.event.demo

openage.game.main_cpp

openage.gamestate.tests

openage.log.log_cpp

openage.main.main_cpp

openage.main.tests

[TheJJ]

thanks - we already have pending pull request fix in #1792, but that needs another update.
if you're willing to contribute your own patch, please submit a pull request!