$ ./pants --version
23:01:10.36 [INFO] Initializing scheduler...
23:01:10.52 [INFO] Scheduler initialized.
2.6.0rc0

./project-app/BUILD ./project-app/pyproject.toml ./project-app/src/app.py

poetry_requirements()

pex_binary(
    name="project-app-pex",
    entry_point="src/app.py",
    zip_safe=False,
)


python_tests(
    name="tests",
    sources=["test_*.py"],
    timeout=120,
)

$ ./pants run project-app:project-app-pex -lerror
23:03:12.60 [ERROR] Exception caught: (pants.engine.internals.scheduler.ExecutionError)
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/bin/local_pants_runner.py", line 234, in _run_inner
    return self._perform_run(goals)
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/bin/local_pants_runner.py", line 173, in _perform_run
    return self._perform_run_body(goals, poll=False)
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/bin/local_pants_runner.py", line 190, in _perform_run_body
    return self.graph_session.run_goal_rules(
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/init/engine_initializer.py", line 135, in run_goal_rules
    exit_code = self.scheduler_session.run_goal_rule(
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/engine/internals/scheduler.py", line 533, in run_goal_rule
    self._raise_on_error([t for _, t in throws])
  File "/home/ehiggs/.cache/pants/setup/bootstrap-Linux-x86_64/2.6.0rc0_py39/lib/python3.9/site-packages/pants/engine/internals/scheduler.py", line 501, in _raise_on_error
    raise ExecutionError(

Exception message: 1 Exception encountered:

  MappingError: Failed to parse project-app/BUILD:
Name 'poetry_requirements' is not defined.

If you expect to see more symbols activated in the below list, refer to (<https://www.pantsbuild.org/v2.6/docs/enabling-backends>) for all available backends to activate.

All registered symbols: ['_python_requirements_file', 'archive', 'files', 'pants_requirement', 'pex_binary', 'pipenv_requirements', 'python_artifact', 'python_distribution', 'python_library', 'python_requirement_library', 'python_requirements', 'python_tests', 'relocated_files', 'resources', 'setup_py', 'target']