Source code for simvx.editor.error_nav

"""Error-navigation helpers — extract source locations from Python tracebacks."""

import re
from pathlib import Path

__all__ = ["parse_traceback_source"]

_FRAME_RE = re.compile(r'File "([^"]+)", line (\d+)')



def parse_traceback_source(
    tb: str, project_path: Path | str | None = None,
) -> tuple[str, int] | None:
    """Return ``(file_path, line)`` of the last user frame in *tb*, or ``None``.

    When *project_path* is given, the last frame whose path sits inside the
    project wins — this hides engine/site-packages frames that sandwich user
    code in real tracebacks. Falls back to the last ``File "…", line N`` match
    overall if no project-local frame is present.
    """
    frames = _FRAME_RE.findall(tb)
    if not frames:
        return None

    if project_path is not None:
        try:
            root = Path(project_path).resolve()
        except (OSError, ValueError):
            root = None
        if root is not None:
            for path_str, line_str in reversed(frames):
                try:
                    candidate = Path(path_str).resolve()
                except (OSError, ValueError):
                    continue
                try:
                    candidate.relative_to(root)
                except ValueError:
                    continue
                return str(candidate), int(line_str)

    path_str, line_str = frames[-1]
    return path_str, int(line_str)