mempalace/tests/test_hooks_shell.py

"""
Integration tests for the legacy ``.sh`` hook scripts.

The shell hooks do their own Python resolution (unlike the Python
``hooks_cli.py`` which uses ``sys.executable`` — trivially correct).
GUI-launched harnesses on macOS provide a minimal PATH that often lacks
the Python where ``mempalace`` is installed, so the shell path needs to:

  1. honour ``$MEMPAL_PYTHON`` as an explicit user override;
  2. fall back to ``$(command -v python3)`` / bare ``python3``;
  3. *never* crash the hook when the resolved interpreter can't import
     mempalace — log and skip the auto-ingest instead, so Claude Code
     doesn't see a non-zero exit from its Stop hook.

These regressions matter because every failure mode they catch produced
silent breakage in production — the user's hook appeared to "not fire"
but was actually crashing deep in a PATH-resolution edge case.
"""

from __future__ import annotations

import json
import os
import stat
import subprocess
import sys
from pathlib import Path

import pytest

REPO_ROOT = Path(__file__).resolve().parent.parent
SAVE_HOOK = REPO_ROOT / "hooks" / "mempal_save_hook.sh"
PRECOMPACT_HOOK = REPO_ROOT / "hooks" / "mempal_precompact_hook.sh"


pytestmark = pytest.mark.skipif(os.name == "nt", reason="bash hook scripts are POSIX-only")


# ── helpers ───────────────────────────────────────────────────────────────


def _write_fake_python(
    path: Path, *, can_import_mempalace: bool = False, marker_file: Path | None = None
) -> Path:
    """Create a python3 shim that proxies to the real interpreter so
    the hook's JSON-parsing calls still work, but fails ``-c 'import
    mempalace'`` / ``-m mempalace`` when ``can_import_mempalace`` is
    False.

    Every invocation appends the shim name to ``marker_file`` so tests
    can prove which interpreter the hook invoked — using a file because
    the hook pipes some python calls to ``2>/dev/null``, so stderr
    markers are unreliable."""
    real_python = sys.executable
    marker = str(marker_file) if marker_file is not None else ""
    shim_src = f"""#!/bin/bash
# Fake python3 shim: proxy to the real interpreter, drop a marker,
# and simulate a missing mempalace install when configured that way.
MARKER_FILE="{marker}"
if [ -n "$MARKER_FILE" ]; then
    echo "{path.name}" >> "$MARKER_FILE"
fi
CAN_IMPORT={"1" if can_import_mempalace else "0"}
# Simulate the "mempalace is not installed in this interpreter" case.
if [ "$CAN_IMPORT" = "0" ]; then
    if [ "$1" = "-c" ] && echo "$2" | grep -q "import mempalace"; then
        exit 1
    fi
    if [ "$1" = "-m" ] && [ "$2" = "mempalace" ]; then
        exit 1
    fi
fi
# Everything else — JSON parsing, heredoc stdin, etc — delegate to real python.
exec "{real_python}" "$@"
"""
    path.write_text(shim_src)
    path.chmod(path.stat().st_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH)
    return path


def _run_hook(
    script: Path,
    stdin_json: dict,
    *,
    env_overrides: dict | None = None,
    path_prefix: list[Path] | None = None,
) -> subprocess.CompletedProcess:
    """Invoke a shell hook with a minimal controlled environment."""
    env = {
        # Give the hook a clean slate — no inherited MEMPAL_* vars.
        "HOME": os.environ.get("HOME", "/tmp"),
        "PATH": os.environ.get("PATH", "/usr/bin:/bin"),
    }
    if path_prefix:
        env["PATH"] = os.pathsep.join(str(p) for p in path_prefix) + os.pathsep + env["PATH"]
    if env_overrides:
        env.update(env_overrides)
    return subprocess.run(
        ["bash", str(script)],
        input=json.dumps(stdin_json),
        capture_output=True,
        text=True,
        env=env,
        timeout=30,
    )


# ── MEMPAL_PYTHON resolution contract ────────────────────────────────────


class TestMempalPythonOverride:
    def test_explicit_override_wins_over_path(self, tmp_path):
        """If MEMPAL_PYTHON is set and executable, the hook must use it
        in preference to whatever is on PATH."""
        marker = tmp_path / "markers.log"
        fake = _write_fake_python(
            tmp_path / "override_python",
            can_import_mempalace=True,
            marker_file=marker,
        )
        result = _run_hook(
            SAVE_HOOK,
            {"session_id": "abc", "stop_hook_active": False, "transcript_path": ""},
            env_overrides={"MEMPAL_PYTHON": str(fake), "HOME": str(tmp_path)},
        )
        assert (
            result.returncode == 0
        ), f"hook exited non-zero: stderr={result.stderr!r} stdout={result.stdout!r}"
        invocations = marker.read_text().splitlines() if marker.exists() else []
        assert (
            "override_python" in invocations
        ), f"MEMPAL_PYTHON override was not used. Marker log: {invocations!r}"

    def test_ignores_override_when_not_executable(self, tmp_path):
        """If MEMPAL_PYTHON is set but the file isn't executable, the
        hook must fall back to PATH rather than blow up with a
        'permission denied'."""
        bogus = tmp_path / "not_executable"
        bogus.write_text("# not a python")
        # Do NOT chmod +x — the hook should notice and skip.
        result = _run_hook(
            SAVE_HOOK,
            {"session_id": "abc", "stop_hook_active": False, "transcript_path": ""},
            env_overrides={"MEMPAL_PYTHON": str(bogus), "HOME": str(tmp_path)},
        )
        assert (
            result.returncode == 0
        ), f"hook crashed on non-executable MEMPAL_PYTHON: {result.stderr!r}"

    def test_falls_back_to_path_when_unset(self, tmp_path):
        """With MEMPAL_PYTHON unset, the hook uses whatever ``python3``
        is found on PATH. Prove this by putting a marker-emitting shim
        first on PATH."""
        marker = tmp_path / "markers.log"
        fake = _write_fake_python(
            tmp_path / "python3",
            can_import_mempalace=True,
            marker_file=marker,
        )
        result = _run_hook(
            SAVE_HOOK,
            {"session_id": "abc", "stop_hook_active": False, "transcript_path": ""},
            env_overrides={"MEMPAL_PYTHON": "", "HOME": str(tmp_path)},
            path_prefix=[fake.parent],
        )
        assert result.returncode == 0
        invocations = marker.read_text().splitlines() if marker.exists() else []
        assert (
            "python3" in invocations
        ), f"fallback-to-PATH did not use the shimmed python3. Marker log: {invocations!r}"