Wrong-shape JSON from a candidate aborts discovery #197

#!/usr/bin/env python3
import shutil
import subprocess
import tempfile
from pathlib import Path


def find_python311_with_first_on_path(candidate):
    """Run the embedder with `candidate` as the first python3.11 on PATH; the real /usr/bin/python3.11 comes after it."""
    with tempfile.TemporaryDirectory() as scratch:
        fake_python = Path(scratch, "bin", "python3.11")
        fake_python.parent.mkdir()
        shutil.copy(f"/tmp/repro.d/{candidate}", fake_python)
        fake_python.chmod(0o755)  # repro.d is mounted without exec bits

        embedder = subprocess.run(
            [
                "/opt/venv/bin/python",
                "/tmp/repro.d/find_python311.py",
                f"{fake_python.parent}:/usr/bin",
                f"{scratch}/cache",
            ],
            capture_output=True,
            text=True,
            timeout=60,
        )

        print(f"--- first python3.11 on PATH is {candidate}")
        print("it was probed as:")
        print(Path(f"{fake_python}.argv").read_text(), end="")
        print("get_interpreter() returned:", embedder.stdout.strip() or "nothing")
        print("embedder stderr, last lines:")
        print("\n".join(embedder.stderr.strip().splitlines()[-4:]))
        print()
        return embedder


# control: output that is not JSON is a failed probe; the candidate is skipped and /usr/bin/python3.11 is found
not_json = find_python311_with_first_on_path("candidate_not_json.sh")

# trigger: output that is valid JSON, but not the object _py_info_collect.py prints
empty_object = find_python311_with_first_on_path("candidate_empty_object.sh")
version_info_only = find_python311_with_first_on_path("candidate_version_info_only.sh")

# check: a JSON candidate must be skipped like the control, not end discovery with an exception
control_skipped = "exe=/usr/bin/python3.11," in not_json.stdout
empty_object_escaped = empty_object.stderr.rstrip().endswith("KeyError: 'version_info'")
version_info_only_escaped = version_info_only.stderr.rstrip().endswith(
    "AttributeError: 'PathPythonInfo' object has no attribute 'original_executable'"
)
print("BUG" if control_skipped and (empty_object_escaped or version_info_only_escaped) else "OK")

"""An embedder such as virtualenv or tox: ask python-discovery for python3.11 on a given PATH and print what it chose."""

import sys
from pathlib import Path

from python_discovery import DiskCache, get_interpreter

search_path, cache_dir = sys.argv[1], sys.argv[2]
# HOME points at nothing so that only PATH is searched, not a uv store
interpreter = get_interpreter(
    "python3.11",
    cache=DiskCache(Path(cache_dir)),
    env={"PATH": search_path, "HOME": "/nonexistent"},
)
print(interpreter)