liblldb cannot find python installation

[danobi]

Describe the bug

When bpftrace is linked against liblldb and tries to initialize it, we get the error:

Python path configuration:
  PYTHONHOME = (not set)
  PYTHONPATH = (not set)
  program name = 'python3'
  isolated = 0
  environment = 1
  user site = 1
  safe_path = 0
  import site = 1
  is in build tree = 0
  stdlib dir = '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9/lib/python3.11'
  sys._base_executable = '/usr/bin/python3'
  sys.base_prefix = '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9'
  sys.base_exec_prefix = '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9'
  sys.platlibdir = 'lib'
  sys.executable = '/usr/bin/python3'
  sys.prefix = '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9'
  sys.exec_prefix = '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9'
  sys.path = [
    '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9/lib/python311.zip',
    '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9/lib/python3.11',
    '/nix/store/7hnr99nxrd2aw6lghybqdmkckq60j6l9-python3-3.11.9/lib/python3.11/lib-dynload',
  ]
Fatal Python error: init_fs_encoding: failed to get the Python codec of the filesystem encoding
Python runtime state: core initialized
LookupError: no codec search functions registered: can't find encoding

Current thread 0x000072dd680c07c0 (most recent call first):
  <no Python frame>

Steps To Reproduce

Steps to reproduce the behavior:

1. clone bpftrace repo (https://github.com/bpftrace/bpftrace)
2. nix build .#appimage
3. echo "int main() {return 0;}" | gcc -g -x c -
4. sudo ./result -e 'uprobe:./a.out:main { @ = count(); }'

Expected behavior

Not to get this error

Additional context

When I set PYTHONPATH to my host stdlib location it seems to work better (but still has odd errors):

$ sudo PYTHONPATH=/usr/lib/python3.12 ./result -e 'uprobe:./a.out:main { @ = count(); }'
Could not find platform independent libraries <prefix>
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'lldb.embedded_interpreter'
Attaching 1 probe...
^C

@: 0

Maybe it's an issue with PYTHONPATH? I see some magic is being done for the lldb executable here:

nixpkgs/pkgs/development/compilers/llvm/common/lldb.nix

Line 162 in 63d37cc

wrapProgram $out/bin/lldb --prefix PYTHONPATH : $lib/${python3.sitePackages}/

Alternatively would it make sense to provide a build option to not build with language support?

Notify maintainers

@dtzWill
@Ericson2314
@lovek323
@qyliss
@RossComputerGuy
@rrbutani
@sternenseemann

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.8.7-arch1-2, Arch Linux, noversion, rolling`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.17.0`
 - nixpkgs: `/home/dxu/.nix-defexpr/channels/nixpkgs`

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[danobi]

Nevermind, turns out we're stripping python files out of the appimage. Sorry for the noise

[baiwfg2]

@danobi Hi, I met with this problem today. What does that mean ? How to solve it ?

[danobi]

Hi @baiwfg2 , this was fixed on bpftrace side in bpftrace/bpftrace@0e71958 . Please check that your build contains that commit