UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 16800744: invalid start byte

[butterflyhigh]

Describe the bug When I try to run meson setup while chrooted into a minimal Linux system, it fails due to the unicode error in the title. It does not fail on the host system.

The output of meson setup from chroot:

The Meson build system
Version: 1.5.0
Source dir: /home/portage
Build dir: /home/portage/build
Build type: native build
Project name: portage
Project version: 3.0.65
C compiler for the host machine: clang (clang 18.1.8 "clang version 18.1.8")
C linker for the host machine: clang ld.bfd 2.42.0
Host machine cpu family: x86_64
Host machine cpu: x86_64
Program python3 found: YES (/usr/bin/python)
Program sed found: YES (/usr/bin/sed)
Configuring const.py using configuration
Configuring installation.py using configuration
Configuring __init__.py using configuration
Configuring AbstractEbuildProcess.py using configuration
Configuring create_depgraph_params.py using configuration
Found pkg-config: YES (/usr/bin/pkg-config) 2.1.1
Run-time dependency python found: YES 3.12
Configuring METADATA using configuration
Program patch found: YES (/usr/bin/patch)
Configuring make.conf.example with command
Program sphinx-apidoc found: NO
Program sphinx-build found: NO
Configuring version using configuration
Program xmlto found: NO
Configuring color.map.5 using configuration
Configuring dispatch-conf.1 using configuration
Configuring ebuild.1 using configuration
Configuring ebuild.5 using configuration
Configuring egencache.1 using configuration
Configuring emaint.1 using configuration
Configuring emerge.1 using configuration
Configuring emirrordist.1 using configuration
Configuring env-update.1 using configuration
Configuring etc-update.1 using configuration
Configuring fixpackages.1 using configuration
Configuring glsa-check.1 using configuration
Configuring make.conf.5 using configuration
Configuring portage.5 using configuration
Configuring quickpkg.1 using configuration
Configuring xpak.5 using configuration
Configuring color.map.5 using configuration
Configuring dispatch-conf.1 using configuration
Configuring ebuild.1 using configuration
Configuring env-update.1 using configuration
Configuring etc-update.1 using configuration
Configuring fixpackages.1 using configuration
Build targets in project: 1

Found ninja-1.12.1 at /usr/bin/ninja
Traceback (most recent call last):                                                                                                                                                                                
  File "/usr/lib/python3.12/site-packages/mesonbuild/mesonmain.py", line 188, in run
    return options.run_func(options)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/msetup.py", line 364, in run
    app.generate()
  File "/usr/lib/python3.12/site-packages/mesonbuild/msetup.py", line 187, in generate
    return self._generate(env, capture, vslite_ctx)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/msetup.py", line 252, in _generate
    captured_compile_args = intr.backend.generate(capture, vslite_ctx)
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/backend/ninjabackend.py", line 648, in generate
    self.generate_target(t)
  File "/usr/lib/python3.12/site-packages/mesonbuild/backend/ninjabackend.py", line 1048, in generate_target
    o, s = self.generate_single_compile(target, src, False, [],
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/backend/ninjabackend.py", line 2984, in generate_single_compile
    self.create_target_source_introspection(target, compiler, commands, [src], [], unity_sources)
  File "/usr/lib/python3.12/site-packages/mesonbuild/backend/ninjabackend.py", line 822, in create_target_source_introspection
    parameters = parameters.to_native(copy=True)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/compilers/mixins/clike.py", line 92, in to_native
    default_dirs = self.compiler.get_default_include_dirs()
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/compilers/mixins/gnu.py", line 402, in get_default_include_dirs
    return gnulike_default_include_dirs(tuple(self.get_exelist(ccache=False)), self.language).copy()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/compilers/mixins/gnu.py", line 327, in gnulike_default_include_dirs
    _, stdout, _ = mesonlib.Popen_safe(cmd, stderr=subprocess.STDOUT, env=env)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/mesonbuild/utils/universal.py", line 1554, in Popen_safe
    o, e = p.communicate(write)
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/subprocess.py", line 1196, in communicate
    stdout = self.stdout.read()
             ^^^^^^^^^^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 16800744: invalid start byte

ERROR: Unhandled python exception

    This is a Meson bug and should be reported!

The output of meson setup from the host system (Arch Linux):

The Meson build system
Version: 1.5.0
Source dir: /home/coolkid/portage
Build dir: /home/coolkid/portage/build
Build type: native build
Project name: portage
Project version: 3.0.65
C compiler for the host machine: ccache cc (gcc 14.1.1 "cc (GCC) 14.1.1 20240522")
C linker for the host machine: cc ld.bfd 2.42.0
Host machine cpu family: x86_64
Host machine cpu: x86_64
Program python3 found: YES (/usr/bin/python)
Program sed found: YES (/usr/bin/sed)
Configuring const.py using configuration
Configuring installation.py using configuration
Configuring __init__.py using configuration
Configuring AbstractEbuildProcess.py using configuration
Configuring create_depgraph_params.py using configuration
Found pkg-config: YES (/usr/bin/pkg-config) 2.1.1
Run-time dependency python found: YES 3.12
Configuring METADATA using configuration
Program patch found: YES (/usr/bin/patch)
Configuring make.conf.example with command
Program sphinx-apidoc found: NO
Program sphinx-build found: NO
Configuring version using configuration
Program xmlto found: NO
Configuring color.map.5 using configuration
Configuring dispatch-conf.1 using configuration
Configuring ebuild.1 using configuration
Configuring ebuild.5 using configuration
Configuring egencache.1 using configuration
Configuring emaint.1 using configuration
Configuring emerge.1 using configuration
Configuring emirrordist.1 using configuration
Configuring env-update.1 using configuration
Configuring etc-update.1 using configuration
Configuring fixpackages.1 using configuration
Configuring glsa-check.1 using configuration
Configuring make.conf.5 using configuration
Configuring portage.5 using configuration
Configuring quickpkg.1 using configuration
Configuring xpak.5 using configuration
Configuring color.map.5 using configuration
Configuring dispatch-conf.1 using configuration
Configuring ebuild.1 using configuration
Configuring env-update.1 using configuration
Configuring etc-update.1 using configuration
Configuring fixpackages.1 using configuration
Build targets in project: 1

Found ninja-1.12.1 at /usr/bin/ninja

To Reproduce The repository being built

Expected behavior I expected it to build successfully.

system parameters

• Is this a cross build or just a plain native build (for the same computer)? No, it is on a different drive but sharing the same CPU
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.)? The problematic system was created by pacstraping the Linux kernel and several useful programs, but without pacman or other arch-specific programs. uname -srm outputs Linux 6.9.9-arch1-1 x86_64
• what Python version are you using e.g. 3.8.0? Python 3.12.4
• what meson --version? 1.5.0
• what ninja --version if it's a Ninja build? 1.12.1

[eli-schwartz]

The error message comes from here: https://github.com/mesonbuild/meson/blob/864919973f73ec2c6ae6ca01be7fe5e8b950df12/mesonbuild/compilers/mixins/gnu.py#L320-L327

Inside the chroot, you have clang 18, and it attempts to:

• export LC_ALL=C into the subprocess
• fork and run: clang -xc -E -v -
• close stdin and read stdout+stderr

This apparently fails because the combination of stdout and stderr for clang when told to use the C locale, is... not utf-8? This does not seem like a thing that should happen.