Hmbown/CodeWhale · error · PersistenceBacklogError

budget fixture. must remain

Error message

budget fixture.{field} must remain {expected!r}

What it means

After the key-set check, validate_budget compares each fixture field's type and value against the script's frozen FIXTURE constants. If any fixture field was changed (e.g. requests_attempted bumped from 128 to 256), the budget describes a different workload than the one the ceilings were calibrated for, so the check fails with this field-specific message naming the expected value.

Solutions

1. Revert the edited fixture field to the exact frozen value reported in the error message
2. Regenerate the budget from the current measurement pipeline
3. If the workload must change, update FIXTURE in the script first and recalibrate ceilings and baseline_observation in the same commit

Example fix

// before
"requests_attempted": 256
// after
"requests_attempted": 128

from check_persistence_backlog_budget import FIXTURE
fixture = budget.get("fixture", {})
for field, expected in FIXTURE.items():
    assert type(fixture.get(field)) is type(expected) and fixture.get(field) == expected, f"fixture.{field} must remain {expected!r}"

def fixture_matches(doc):
    f = doc.get("fixture") if isinstance(doc, dict) else None
    return isinstance(f, dict) and all(type(f.get(k)) is type(v) and f.get(k) == v for k, v in FIXTURE.items())

try:
    validate_budget(budget)
except PersistenceBacklogError as e:
    if ".must remain" in str(e) and "fixture" in str(e):
        print("restore the frozen fixture value named in the message")
    raise

When it happens

Trigger: compare calls validate_budget and any fixture field differs in type (strict type() check, so true vs 1 fails) or value from FIXTURE, e.g. content_bytes_per_request changed or expected_applied_version edited.

Common situations: Tuning the workload numbers by hand in the budget JSON to make a failing ceiling pass; editing fixture values with a different numeric type (float 128.0 instead of int 128); stale budget from a pre-existing fixture revision.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• baseline_observation.accepted_requests must equal…
• budget fixture no longer matches the frozen workload
• applied_version is not the final sent version
• baseline_observation.
• budget baseline_receipt path changed

AI-assisted analysis of Hmbown/CodeWhale@433685b202 (2026-09-15). Data as JSON: /api/errors/11edfe07c17b67e4. Report an issue: GitHub.

Appendix: source

Thrown at scripts/check-persistence-backlog-budget.py:252

        if receipt["rss_after_delta_bytes"] != max(
            0, receipt["rss_after_bytes"] - before
        ):
            raise PersistenceBacklogError("rss_after_delta_bytes is inconsistent")
    elif any(receipt[field] is not None for field in rss_fields):
        raise PersistenceBacklogError("unsupported RSS fields must be null")


def validate_budget(budget: dict[str, Any]) -> None:
    if budget.get("document_kind") != BUDGET_KIND:
        raise PersistenceBacklogError(f"budget document_kind must be {BUDGET_KIND}")
    if budget.get("schema_version") != SCHEMA_VERSION:
        raise PersistenceBacklogError("budget schema_version changed")
    fixture = budget.get("fixture")
    if not isinstance(fixture, dict) or set(fixture) != set(FIXTURE):
        raise PersistenceBacklogError("budget fixture no longer matches the frozen workload")
    for field, expected in FIXTURE.items():
        if type(fixture[field]) is not type(expected) or fixture[field] != expected:
            raise PersistenceBacklogError(
                f"budget fixture.{field} must remain {expected!r}"
            )
    if budget.get("baseline_receipt") != BASELINE_RECEIPT_REFERENCE:
        raise PersistenceBacklogError("budget baseline_receipt path changed")
    ceilings = budget.get("ceilings")
    baseline = budget.get("baseline_observation")
    if not isinstance(ceilings, dict) or not isinstance(baseline, dict):
        raise PersistenceBacklogError("budget needs ceilings and baseline_observation objects")
    for field in CEILING_FIELDS:
        ceiling = non_negative_integer(ceilings.get(field), f"ceilings.{field}")
        observed = non_negative_integer(
            baseline.get(field), f"baseline_observation.{field}"
        )
        if observed > ceiling:
            raise PersistenceBacklogError(
                f"baseline_observation.{field} exceeds its ceiling"
            )
    baseline_accepted = non_negative_integer(

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