abhigyanpatwari/GitNexus · error · SandboxError

required executable is not an executable regular file: {path

Error message

required executable is not an executable regular file: {path}

What it means

Raised by _resolve_executable after locating the candidate path: Path(raw).resolve() either is not a regular file or os.access(path, X_OK) is false. The sandbox will not exec something that is a directory, a broken symlink, a non-executable file, or a file the current user cannot execute.

Source

Thrown at eval/workflow_bench/proposer_sandbox.py:470

    evidence-provenance.mjs's PATH-scan correctly refuses to trust. This
    wrapper is freshly created by the same host process that owns
    home/temp/shell-prefix, so it maps to the sandbox's own trusted uid
    instead, and simply execs the real interpreter through to do the work.
    """

    wrapper = private_root / "python3"
    wrapper.write_text('#!/bin/bash\nset -eu\nexec /usr/bin/python3 "$@"\n')
    wrapper.chmod(0o500)
    return wrapper


def _resolve_executable(executable: Path | str | None, default: str) -> Path:
    raw = os.fspath(executable) if executable is not None else shutil.which(default)
    if not raw:
        raise SandboxError(f"required executable is unavailable: {default}")
    path = Path(raw).expanduser().resolve()
    if not path.is_file() or not os.access(path, os.X_OK):
        raise SandboxError(f"required executable is not an executable regular file: {path}")
    return path


def preflight_bubblewrap(bwrap_bin: Path | str | None = None) -> Path:
    """Prove the required namespaces work; never fall back to host execution."""

    if sys.platform != "linux":
        raise SandboxError(f"Bubblewrap containment is supported only on Linux/WSL2, not {sys.platform}")
    bwrap = _resolve_executable(bwrap_bin, "bwrap")
    command = [
        str(bwrap),
        "--unshare-user",
        "--unshare-pid",
        "--unshare-ipc",
        "--unshare-uts",
        "--die-with-parent",
        "--new-session",
        *_runtime_mount_args(),

View on GitHub (pinned to d540b00184)

Solutions

1. chmod +x the target file if it should be executable.
2. Point at the real binary, not a directory or shim: pass the absolute path to the executable file.
3. Reinstall the tool if its binary was removed/corrupted.
4. Check permissions: ls -l path and ensure an x bit for the current user; fix mount options if noexec.

Example fix

// before
node = _resolve_executable('/opt/claude/nodejs', 'node')  # a directory
// after
node = _resolve_executable('/opt/claude/nodejs/bin/node', 'node')
Path(node).chmod(0o755)

import os
from pathlib import Path

def is_executable_file(p: Path) -> bool:
    return p.is_file() and os.access(p, os.X_OK)

exe = Path(shutil.which('node'))
assert is_executable_file(exe)
_resolve_executable(str(exe), 'node')

import os
from pathlib import Path

def is_executable_regular_file(value: object) -> bool:
    if not isinstance(value, Path):
        return False
    return value.is_file() and os.access(value, os.X_OK)

try:
    path = _resolve_executable(candidate, 'node')
except SandboxError as exc:
    if 'not an executable regular file' in str(exc):
        path.chmod(0o755)
        path = _resolve_executable(candidate, 'node')
    raise

When it happens

Trigger: An explicit executable argument (or a which() result) points to a directory, a file without the executable bit, a symlink whose target is missing/non-executable, or a path the current user cannot execute.

Common situations: Wrapper script created without chmod +x; path points at a directory (e.g. /opt/claude/nodejs instead of the node binary); filesystem mounted noexec; broken symlink returned by a stale which cache; running as a user without execute rights on the binary (permissions 0o644); a pyenv/asdf shim that lost its target after an uninstall.

Related errors

• transcript artifact parent must be owner-only: {current}
• Compound Engineering plugin directory is unreadable: {direct
• sandbox_copy directory is unreadable: {relative}: {exc}
• Could not read ${GITNEXUS_RC_FILENAME}: ${(err as Error).mes
• candidate destination parent must be a real directory: {rela

AI-assisted analysis of abhigyanpatwari/GitNexus@d540b00184 (2026-08-12). Data as JSON: /api/errors/1d1eb09e35f19870. Report an issue: GitHub.