transcription/tests/test_error_message_safety.py

"""AST guards for user-facing error safety and UI failure-detail rendering."""

from __future__ import annotations

import ast
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[1]
SOURCE_DIR = PROJECT_ROOT / "src" / "transcription"
UI_DIR = SOURCE_DIR / "ui"

_RAW_DETAIL_ATTRIBUTES = frozenset({"error_detail", "latest_error_detail"})
_SUSPICIOUS_FORMATTED_NAMES = frozenset({"path", "root", "dir", "exc", "err", "e"})


def _python_files(root: Path) -> list[Path]:
    return sorted(root.rglob("*.py"))


def _parent_map(tree: ast.AST) -> dict[ast.AST, ast.AST]:
    parents: dict[ast.AST, ast.AST] = {}
    for node in ast.walk(tree):
        for child in ast.iter_child_nodes(node):
            parents[child] = node
    return parents


def _is_wrapped_in_display_failure_detail(node: ast.AST, parents: dict[ast.AST, ast.AST]) -> bool:
    current = node
    while current in parents:
        current = parents[current]
        if not isinstance(current, ast.Call):
            continue
        func = current.func
        if isinstance(func, ast.Name) and func.id == "display_failure_detail":
            return True
    return False


def _ui_raw_detail_reads() -> dict[str, list[int]]:
    violations: dict[str, list[int]] = {}
    for path in _python_files(UI_DIR):
        tree = ast.parse(path.read_text(encoding="utf-8"))
        parents = _parent_map(tree)
        found = sorted(
            node.lineno
            for node in ast.walk(tree)
            if isinstance(node, ast.Attribute)
            and node.attr in _RAW_DETAIL_ATTRIBUTES
            and not _is_wrapped_in_display_failure_detail(node, parents)
        )
        if found:
            violations[str(path.relative_to(PROJECT_ROOT)).replace("\\", "/")] = found
    return violations


def _class_bases_by_name() -> dict[str, set[str]]:
    bases: dict[str, set[str]] = {}
    for path in _python_files(SOURCE_DIR):
        tree = ast.parse(path.read_text(encoding="utf-8"))
        for node in tree.body:
            if not isinstance(node, ast.ClassDef):
                continue
            inherited = set()
            for base in node.bases:
                if isinstance(base, ast.Name):
                    inherited.add(base.id)
                elif isinstance(base, ast.Attribute):
                    inherited.add(base.attr)
            bases[node.name] = inherited
    return bases


def _app_error_subclasses() -> set[str]:
    bases = _class_bases_by_name()
    subclasses = {"AppError"}
    changed = True
    while changed:
        changed = False
        for name, inherited in bases.items():
            if name in subclasses:
                continue
            if inherited & subclasses:
                subclasses.add(name)
                changed = True
    subclasses.remove("AppError")
    return subclasses


def _formatted_name_ids(node: ast.AST) -> set[str]:
    return {child.id for child in ast.walk(node) if isinstance(child, ast.Name)}


def _is_safe_basename_projection(node: ast.AST) -> bool:
    return isinstance(node, ast.Attribute) and node.attr == "name"


def _is_suspicious_name(name: str) -> bool:
    if name in _SUSPICIOUS_FORMATTED_NAMES:
        return True
    return any(name.endswith(f"_{suffix}") for suffix in _SUSPICIOUS_FORMATTED_NAMES - {"e"})


def _user_message_interpolation_violations() -> dict[str, list[str]]:
    violations: dict[str, list[str]] = {}
    error_types = _app_error_subclasses()
    for path in _python_files(SOURCE_DIR):
        tree = ast.parse(path.read_text(encoding="utf-8"))
        found: list[str] = []
        for node in ast.walk(tree):
            if not isinstance(node, ast.Raise):
                continue
            if not isinstance(node.exc, ast.Call):
                continue
            func = node.exc.func
            if not isinstance(func, ast.Name) or func.id not in error_types:
                continue
            if not node.exc.args:
                continue
            message = node.exc.args[0]
            if not isinstance(message, ast.JoinedStr):
                continue
            formatted_names = {
                name
                for value in message.values
                if isinstance(value, ast.FormattedValue)
                if not _is_safe_basename_projection(value.value)
                for name in _formatted_name_ids(value.value)
            }
            suspicious = sorted(name for name in formatted_names if _is_suspicious_name(name))
            if suspicious:
                found.append(f"L{node.lineno}: {', '.join(suspicious)}")
        if found:
            violations[str(path.relative_to(PROJECT_ROOT)).replace("\\", "/")] = found
    return violations


def test_ui_modules_only_render_failure_detail_through_projection():
    """HIGH-01: UI must sanitize persisted failure detail before rendering it."""
    assert _ui_raw_detail_reads() == {}


def test_user_facing_app_error_messages_do_not_interpolate_paths_or_exceptions():
    """HIGH-02 / MED-07: keep paths and exception text out of AppError.message."""
    assert _user_message_interpolation_violations() == {}