nexu-io/open-design · error · SystemExit

running-left mirror output must be decoded/running-left.png

Error message

running-left mirror output must be decoded/running-left.png

What it means

Raised by validate_mirror_hash when the running-left job's output_path does not point at decoded/running-left.png. The finalize stage consumes the decoded/ sibling, so the manifest's output location is contract-locked to that exact filename and parent.

Source

Thrown at skills/hatch-pet/scripts/finalize_pet_run.py:106

        raise SystemExit(
            "running-left mirror job is missing an approved mirror_decision; "
            "use derive_running_left_from_running_right.py after visual review"
        )

    expected_source_hash = job.get("source_sha256")
    expected_output_hash = job.get("output_sha256")
    if not isinstance(expected_source_hash, str) or not expected_source_hash:
        raise SystemExit("running-left mirror job is missing source_sha256")
    if not isinstance(expected_output_hash, str) or not expected_output_hash:
        raise SystemExit("running-left mirror job is missing output_sha256")
    if not source.is_file():
        raise SystemExit(f"running-left mirror source image no longer exists: {source}")
    if not output.is_file():
        raise SystemExit(f"running-left mirrored output is missing: {output}")
    if source.name != "running-right.png" or source.parent.name != "decoded":
        raise SystemExit("running-left mirror source must be decoded/running-right.png")
    if output.name != "running-left.png" or output.parent.name != "decoded":
        raise SystemExit("running-left mirror output must be decoded/running-left.png")
    if file_sha256(source) != expected_source_hash:
        raise SystemExit("running-left mirror source hash does not match imagegen-jobs.json")
    if file_sha256(output) != expected_output_hash:
        raise SystemExit(
            "running-left mirrored output hash does not match imagegen-jobs.json; "
            "rerun derive_running_left_from_running_right.py"
        )
    with Image.open(source) as source_image, Image.open(output) as output_image:
        expected = ImageOps.mirror(source_image.convert("RGBA"))
        actual = output_image.convert("RGBA")
        if expected.size != actual.size or expected.tobytes() != actual.tobytes():
            raise SystemExit(
                "running-left mirrored output is not an exact horizontal mirror of running-right"
            )


def validate_completed_job_source(
    job: dict[str, object],

View on GitHub (pinned to 5be4028344)

Solutions

  1. Update the running-left job's output_path in imagegen-jobs.json to decoded/running-left.png.
  2. Re-run derive_running_left_from_running_right.py so it writes the file and records the canonical output_path.
  3. Verify the file actually exists at the corrected location before re-running finalize.

Example fix

// before (imagegen-jobs.json)
"output_path": "raw/running-left.png"
// after
"output_path": "decoded/running-left.png"
Defensive patterns

Strategy: validation

Validate before calling

output = (run_dir / job['output_path']).resolve()
if output.name != 'running-left.png' or output.parent.name != 'decoded':
    raise ValueError('mirror output must be decoded/running-left.png')

Prevention

When it happens

Trigger: job['output_path'] resolves to a path whose .name != 'running-left.png' or whose parent .name != 'decoded'. Caused by manifest edits or a derive script that wrote to the wrong directory.

Common situations: Manually correcting imagegen-jobs.json after moving files; output_path left pointing at raw/running-left.png from an intermediate step.

Related errors

AI-assisted analysis of nexu-io/open-design@5be4028344 (2026-08-12). Data as JSON: /api/errors/8ccb99e43a7a744e. Report an issue: GitHub.