Wardline rules reference¶

Quick-reference for all Wardline rule IDs — canonical pattern rules, supplementary rules, diagnostic signals, and governance findings.

Canonical Rules (Pattern Detection)¶

These nine rules detect structural boundary violations in Python code. All are emitted as Finding objects with taint-gated severity (see Severity Matrix).

PY-WL-001¶

Dict key access with fallback default

Detects: d.get(key, default), d.pop(key, default), d.setdefault(key, default), defaultdict(factory) — patterns that silently fabricate values for missing keys, bypassing validation. schema_default() without a matching overlay boundary also fires here.

Fix: Replace fallback defaults with explicit key access that raises on missing keys; or declare an overlay boundary and use schema_default() inside it.

PY-WL-002¶

Attribute access with fallback default

Detects: Three-argument getattr(obj, name, default) — silently returns a fabricated value when the attribute is absent, masking structural gaps. Two-argument getattr (which raises AttributeError) is not flagged.

Fix: Use two-argument getattr and handle AttributeError explicitly, or access the attribute directly.

PY-WL-003¶

Existence-checking as structural gate

Detects: "key" in d, key not in d, d.get(key) is None, hasattr(obj, name), match/case with MatchMapping or MatchClass — treating presence/absence of a key or attribute as a control-flow branch rather than enforcing known shape up front.

Fix: Validate structure at a declared shape-validation boundary; within the boundary body, direct key/attribute access is permitted.

PY-WL-004¶

Broad exception handler

Detects: Bare except:, except Exception:, except BaseException:, and except* with those broad types — handlers that catch far more than intended, masking unexpected failures.

Fix: Catch specific exception types. If broad handling is required, re-raise after logging or use a governed suppression.

PY-WL-005¶

Silent exception handler

Detects: Exception handlers whose bodies are pass, ..., continue, or break — the exception is caught and completely discarded with no log, re-raise, or side effect.

Fix: Log the exception, re-raise it, or convert it to a domain error with meaningful context.

PY-WL-006¶

Audit-critical write in broad exception handler

Detects: Audit/ledger write calls (e.g. functions decorated @integral_writer / @integrity_critical, calls to audit, record, write_audit, etc.) inside a broad exception handler — if the write itself raises, the handler silently masks the failure and the audit trail loses a record.

Fix: Move audit writes outside broad handlers, or catch only the specific exceptions the write can raise and propagate the rest.

PY-WL-007¶

Runtime type-checking on internal data

Detects: isinstance() and type() == / type() is checks on data that should have a statically known type. Severity is taint-gated: suppressed for EXTERNAL_RAW/UNKNOWN_RAW where type checks are expected; escalated for internal taint states. AST node dispatch, dunder comparison protocol, and frozen-dataclass __post_init__ patterns are structurally suppressed.

Fix: Enforce types at the external boundary with a shape-validation decorator so internal code can rely on the type statically.

PY-WL-008¶

Validation boundary with no rejection path

Detects: A function declared as a validation or restoration boundary (via manifest transition or @validates_shape / @validates_semantic / @validates_external decorator) whose body contains no raised exception or guarded early-return that constitutes a rejection path.

Fix: Add an explicit rejection path — raise a domain exception or return early on invalid input before the function proceeds.

PY-WL-009¶

Semantic validation without prior shape validation

Detects: A function declared as a semantic_validation boundary (or decorated @validates_semantic) that performs semantic checks on data before structural validation has occurred within the same boundary. Combined-validation boundaries are excluded because they satisfy the ordering requirement internally.

Fix: Either precede semantic checks with a call to a shape-validation boundary, or promote the boundary to combined_validation.

Supplementary Rules¶

These rules enforce decorator contracts and cross-cutting structural concerns beyond the nine canonical patterns.

For the full decorator catalogue see Decorators and Supplementary Groups.

Diagnostic Signals¶

These pseudo-rule-IDs appear in SARIF output as informational signals; they are not in implementedRules and cannot be excepted.

Governance Findings¶

Governance findings are emitted by the exception and taint governance subsystems. They record policy events, drift detections, and configuration anomalies. All are pseudo-rule-IDs and cannot themselves be excepted.

For the full governance exception lifecycle see Governance Retention.

Further Reading¶

• Severity Matrix — Taint-state × rule severity matrix
• Decorators — Full wardline decorator catalogue
• Spec §8: Pattern Rules — Semantic boundary enforcement normative requirements
• Semantic Equivalents — Equivalent patterns across languages