Hmbown/CodeWhale · error · PersistenceBacklogError

baseline provenance platform must be macos

Error message

baseline provenance platform must be macos

What it means

Baseline provenance must record platform == "macos" because the persisted backlog budget was calibrated on macOS; comparing measurements from another platform would be apples-to-oranges. The checker raises when the recorded platform differs.

Solutions

  1. Regenerate the baseline on a macOS machine.
  2. If the platform policy intentionally changes, update the checker's expectation and the budget together — don't just edit the JSON.
  3. Verify provenance.platform is exactly "macos" (lowercase) after generation.

Example fix

// before
"provenance": { "platform": "linux", ... }
// after
"provenance": { "platform": "macos", ... }
Defensive patterns

Strategy: validation

Validate before calling

if budget.get("baseline_observation", {}).get("provenance", {}).get("platform") != "macos":
    raise ValueError("baseline must be generated on macOS")

Try / catch

try:
    compare(budget, baseline_receipt)
except PersistenceBacklogError as e:
    if "platform must be macos" in str(e): regenerate on macOS host

Prevention

When it happens

Trigger: `compare` with a baseline generated on linux or windows, or with a typo'd/missing platform string in provenance.

Common situations: Regenerating the baseline on a CI Linux runner or a different developer machine, then committing it over the macos baseline.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@433685b202 (2026-09-15). Data as JSON: /api/errors/5df0d6d3d727e376. Report an issue: GitHub.

Appendix: source

Thrown at scripts/check-persistence-backlog-budget.py:302

    baseline_retained = baseline["retained_queued_requests"]
    baseline_payload = baseline["estimated_retained_payload_bytes"]
    if baseline_retained == 0 or baseline_payload == 0:
        raise PersistenceBacklogError(
            "baseline_observation must retain the final request and payload"
        )
    if baseline_retained > baseline_accepted:
        raise PersistenceBacklogError(
            "baseline_observation.retained_queued_requests exceeds accepted_requests"
        )
    if baseline_payload < baseline_retained * FIXTURE["content_bytes_per_request"]:
        raise PersistenceBacklogError(
            "baseline_observation payload is smaller than frozen retained content"
        )
    provenance = baseline.get("provenance")
    if not isinstance(provenance, dict):
        raise PersistenceBacklogError("baseline_observation needs provenance")
    if provenance.get("platform") != "macos":
        raise PersistenceBacklogError("baseline provenance platform must be macos")
    if not isinstance(provenance.get("source_sha"), str) or not SOURCE_SHA_PATTERN.fullmatch(
        provenance["source_sha"]
    ):
        raise PersistenceBacklogError("baseline provenance needs an exact source SHA")
    if provenance.get("source_dirty") is not False:
        raise PersistenceBacklogError("baseline provenance must identify a clean source tree")
    for field, prefix in (("rustc_version", "rustc "), ("cargo_version", "cargo ")):
        if not isinstance(provenance.get(field), str) or not provenance[field].startswith(prefix):
            raise PersistenceBacklogError(f"baseline provenance needs {field}")
    if provenance.get("build_profile") != "test" or not (
        type(provenance.get("sample_count")) is int
        and provenance["sample_count"] == 1
    ):
        raise PersistenceBacklogError("baseline provenance build profile/sample count changed")


def validate_baseline_receipt(
    budget: dict[str, Any], baseline_receipt: dict[str, Any]

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