oracle/graal · error · ValueError

Environment variable 'ROOTFS' points to '{rootfs}' which is

Error message

Environment variable 'ROOTFS' points to '{rootfs}' which is not a directory!

What it means

Same _resolve_rootfs resolver, but ROOTFS is set and resolves to something that is not a directory (file, nonexistent path, broken symlink). Since the harness will write staged files and create temp directories inside it, it validates is_dir() and raises ValueError with the resolved path.

Source

Thrown at sdk/mx.sdk/mx_sdk_benchmark.py:2254

    def _resolve_graalos_build_dir() -> Path:
        """Verifies that the GRAALOS_BUILD env var is set and points to a directory. Returns the directory path."""
        graalos_build_env_var = os.getenv("GRAALOS_BUILD")
        if graalos_build_env_var is None:
            raise ValueError("Environment variable 'GRAALOS_BUILD' is unset! It must point to the GraalOS build directory!")
        build_dir = Path(graalos_build_env_var).resolve()
        if not build_dir.is_dir():
            raise ValueError(f"Environment variable 'GRAALOS_BUILD' points to '{build_dir}' which is not a directory!")
        return build_dir

    @staticmethod
    def _resolve_rootfs() -> Path:
        """Verifies that the ROOTFS env var is set and points to a directory. Returns the directory path."""
        rootfs_env_var = os.getenv("ROOTFS")
        if rootfs_env_var is None:
            raise ValueError("Environment variable 'ROOTFS' is unset! It must point to the CPython file-system root!")
        rootfs = Path(rootfs_env_var).resolve()
        if not rootfs.is_dir():
            raise ValueError(f"Environment variable 'ROOTFS' points to '{rootfs}' which is not a directory!")
        return rootfs

    @staticmethod
    def _require_executable(path: Path, description: str) -> Path:
        if not path.is_file():
            raise ValueError(f"{description} '{path}' does not exist!")
        if not os.access(path, os.X_OK):
            raise ValueError(f"{description} '{path}' is not executable!")
        return path

    @staticmethod
    def _resolve_graalhost_binary(build_dir: Path) -> Path:
        """Resolve the GraalHost binary from the GraalOS build directory."""
        return GraalHostPolyBenchStagingVm._require_executable(build_dir / "graalhost" / "graalhost", "GraalHost binary")

    @staticmethod
    def _resolve_graalos_config_util() -> Path:
        """Resolve the graalos-config-util CLI from PATH."""

View on GitHub (pinned to a66e9ccd1d)

Solutions

Extract/prepare the CPython root directory and export its absolute path as ROOTFS.
Verify with 'test -d "$ROOTFS" && ls "$ROOTFS"/tmp'.
Re-create rootfs/tmp if it was cleaned.

Example fix

# before
export ROOTFS=$HOME/downloads/cpython-rootfs.tar.gz

# after
export ROOTFS=$HOME/graalos/roots/cpython-rootfs

Defensive patterns

Strategy: validation

Validate before calling

r = Path(os.environ['ROOTFS']).resolve()
assert r.is_dir(), f'ROOTFS={r} is not a directory; extract the CPython rootfs and export its path'

Try / catch

try/except ValueError; print the resolved path plus whether its parent exists to distinguish typos from missing mounts.

Prevention

Export the extracted root directory, never the tarball.
Check mounts (noexec/NFS availability) before runs.

When it happens

Trigger: ROOTFS pointing at a tarball instead of the extracted root, a removed directory, or a typo. Path.resolve() absolutizes, so relative paths that made sense in another cwd fail here.

Common situations: ROOTFS set to the .tar.gz artifact name by mistake; build cleaned between runs; NFS/symlink to an unmounted share.

Related errors

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/d0bc2a57f820b360. Report an issue: GitHub.