Yocto(Zeus) Perf Build fails - yocto

Question

I want to build perf on Yocto (Zeus branch), for an image without python2. The recipe is this one:
https://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/recipes-kernel/perf/perf.bb?h=zeus-22.0.4
Running this recipe yields this error:
| ERROR: Execution of '/home/yocto/poseidon-build/tmp/work/imx6dl_poseidon_revb-poseidon-linux-gnueabi/perf/1.0-r9/temp/run.do_compile.19113' failed with exit code 1:
| make: Entering directory '/home/yocto/poseidon-build/tmp/work/imx6dl_poseidon_revb-poseidon-linux-gnueabi/perf/1.0-r9/perf-1.0/tools/perf'
| BUILD: Doing 'make -j4' parallel build
| Warning: arch/x86/include/asm/disabled-features.h differs from kernel
| Warning: arch/x86/include/asm/required-features.h differs from kernel
| Warning: arch/x86/include/asm/cpufeatures.h differs from kernel
| Warning: arch/arm/include/uapi/asm/perf_regs.h differs from kernel
| Warning: arch/arm64/include/uapi/asm/perf_regs.h differs from kernel
| Warning: arch/powerpc/include/uapi/asm/perf_regs.h differs from kernel
| Warning: arch/x86/include/uapi/asm/perf_regs.h differs from kernel
| Warning: arch/x86/include/uapi/asm/kvm.h differs from kernel
| Warning: arch/x86/include/uapi/asm/kvm_perf.h differs from kernel
| Warning: arch/x86/include/uapi/asm/svm.h differs from kernel
| Warning: arch/x86/include/uapi/asm/vmx.h differs from kernel
| Warning: arch/powerpc/include/uapi/asm/kvm.h differs from kernel
| Warning: arch/s390/include/uapi/asm/kvm.h differs from kernel
| Warning: arch/s390/include/uapi/asm/kvm_perf.h differs from kernel
| Warning: arch/s390/include/uapi/asm/sie.h differs from kernel
| Warning: arch/arm/include/uapi/asm/kvm.h differs from kernel
| Warning: arch/arm64/include/uapi/asm/kvm.h differs from kernel
| Warning: arch/x86/lib/memcpy_64.S differs from kernel
| Warning: arch/x86/lib/memset_64.S differs from kernel
|
| Auto-detecting system features:
| ... dwarf: [ on ]
| ... dwarf_getlocations: [ on ]
| ... glibc: [ on ]
| ... gtk2: [ OFF ]
| ... libaudit: [ OFF ]
| ... libbfd: [ on ]
| ... libelf: [ on ]
| ... libnuma: [ OFF ]
| ... numa_num_possible_cpus: [ OFF ]
| ... libperl: [ OFF ]
| ... libpython: [ on ]
| ... libslang: [ on ]
| ... libcrypto: [ on ]
| ... libunwind: [ on ]
| ... libdw-dwarf-unwind: [ on ]
| ... zlib: [ on ]
| ... lzma: [ on ]
| ... get_cpuid: [ OFF ]
| ... bpf: [ on ]
|
| Makefile.config:352: DWARF support is off, BPF prologue is disabled
| Makefile.config:547: Missing perl devel files. Disabling perl scripting support, please install perl-ExtUtils-Embed/libperl-dev
| Makefile.config:594: Python 3 is not yet supported; please set
| Makefile.config:595: PYTHON and/or PYTHON_CONFIG appropriately.
| Makefile.config:596: If you also have Python 2 installed, then
| Makefile.config:597: try something like:
| Makefile.config:598:
| Makefile.config:599: make PYTHON=python2
| Makefile.config:600:
| Makefile.config:601: Otherwise, disable Python support entirely:
| Makefile.config:602:
| Makefile.config:603: make NO_LIBPYTHON=1
| Makefile.config:604:
| Makefile.config:605: *** . Stop.
| Makefile.perf:205: recipe for target 'sub-make' failed
| make[1]: *** [sub-make] Error 2
| Makefile:68: recipe for target 'all' failed
| make: *** [all] Error 2
| make: Leaving directory '/home/yocto/poseidon-build/tmp/work/imx6dl_poseidon_revb-poseidon-linux-gnueabi/perf/1.0-r9/perf-1.0/tools/perf'
| WARNING: exit code 1 from a shell command.
|
ERROR: Task (/home/yocto/sources/poky/meta/recipes-kernel/perf/perf.bb:do_compile) failed with exit code '1'
NOTE: Tasks Summary: Attempted 1947 tasks of which 1946 didn't need to be rerun and 1 failed.
Looking at the recipe, libpython seems to be set?:
PACKAGECONFIG ??= "scripting tui libunwind"
PACKAGECONFIG[dwarf] = ",NO_DWARF=1"
PACKAGECONFIG[scripting] = ",NO_LIBPERL=1 NO_LIBPYTHON=1,perl python3"
# gui support was added with kernel 3.6.35
# since 3.10 libnewt was replaced by slang
# to cover a wide range of kernel we add both dependencies
PACKAGECONFIG[tui] = ",NO_NEWT=1,libnewt slang"
PACKAGECONFIG[libunwind] = ",NO_LIBUNWIND=1 NO_LIBDW_DWARF_UNWIND=1,libunwind"
PACKAGECONFIG[libnuma] = ",NO_LIBNUMA=1"
PACKAGECONFIG[systemtap] = ",NO_SDT=1,systemtap"
PACKAGECONFIG[jvmti] = ",NO_JVMTI=1"
# libaudit support would need scripting to be enabled
PACKAGECONFIG[audit] = ",NO_LIBAUDIT=1,audit"
PACKAGECONFIG[manpages] = ",,xmlto-native asciidoc-native"
Why does it not pick up the flag?

Answer 1

PACKAGECONFIG has scripting in it by default.
PACKAGECONFIG options are defined as following:
PACKAGECONFIG[f1] = "--with-f1, \
--without-f1, \
build-deps-for-f1, \
runtime-deps-for-f1, \
runtime-recommends-for-f1, \
packageconfig-conflicts-for-f1 \
"
PACKAGECONFIG[scripting] is set to ",NO_LIBPERL=1 NO_LIBPYTHON=1,perl python3". See the first comma here? It means that what is defined after is when scripting is not selected.
So if you do not want python dependency to be pulled, just set PACKAGECONFIG to a value without scripting in it.
Though I'm actually surprised the default does not build, that's definitely something that is tested by autobuilders. There's probably something else going on?
c.f.: https://www.yoctoproject.org/docs/latest/mega-manual/mega-manual.html#var-PACKAGECONFIG