Validation diagnostics¶

Every finding from the scenario validator carries a stable diagnostic code (HTTPCHAINxxx), a severity, a human-readable message and (where meaningful) a location, so tooling can filter, sort and route diagnostics deterministically.

You meet these codes in three places:

pytest-httpchain validate output (and its --format json payload);
pytest collection: error-severity findings fail collection, warnings are emitted as ScenarioValidationWarning in the form [HTTPCHAINxxx] ...;
CI gates: validate --strict exits non-zero on warnings too.

Codes are append-only: a code's meaning never changes, and retired checks do not free their numbers for reuse.

Code reference¶

Code	Severity	Meaning
`HTTPCHAIN000`	error	Schema validation failed (Pydantic `Scenario` model)
`HTTPCHAIN001`	error	Duplicate stage names
`HTTPCHAIN002`	error	Fixture and variable share the same name
`HTTPCHAIN003`	warning	Variable referenced but never defined/saved/fixture (typo)
`HTTPCHAIN004`	warning	Variable referenced before it is saved or defined — saved by a later stage, or defined by a later substitution step (ordering / data-flow)
`HTTPCHAIN005`	warning	Stage has no verify step (no response validation)
`HTTPCHAIN006`	warning	Verify step asserts nothing (no-op)
`HTTPCHAIN007`	error	Body `contains`/`not_contains` list the same substring
`HTTPCHAIN008`	error	Body `matches`/`not_matches` list the same pattern
`HTTPCHAIN009`	warning	Saved variable is shadowed by a scenario-level fixture
`HTTPCHAIN010`	error	File not found
`HTTPCHAIN011`	error	Path is not a file
`HTTPCHAIN012`	error	`$ref` resolution failed
`HTTPCHAIN013`	warning	File extension is not `.json`
`HTTPCHAIN014`	error	Invalid JSON syntax
`HTTPCHAIN015`	error	Failed to parse JSON file
`HTTPCHAIN016`	error	Fixture referenced in a scenario-level template
`HTTPCHAIN017`	error	Scenario-level template references an undefined name
`HTTPCHAIN018`	warning	Verify expression is not a template (`{{ }}`) — asserts nothing
`HTTPCHAIN019`	error	Invalid pytest marker expression (scenario or stage `marks`)
`HTTPCHAIN020`	warning	Referenced file does not exist (deep, opt-in)
`HTTPCHAIN021`	warning	Schema file is not valid JSON / not a valid schema (deep)
`HTTPCHAIN022`	warning	User function cannot be imported (deep)
`HTTPCHAIN023`	warning	Unexpected argument passed to a user function (deep)
`HTTPCHAIN024`	warning	Missing required argument for a user function (deep)
`HTTPCHAIN025`	info	Template parametrize values force collection-time resolution
`HTTPCHAIN026`	warning	`$ref` path matches files under both lookup bases (ambiguous)
`HTTPCHAIN027`	warning	User-defined name shadowed by the reserved `response` namespace
`HTTPCHAIN028`	warning	Scenario directive (`$include`/`$merge`, or file-path `$ref`) inside an inline JSON Schema — not resolved there
`HTTPCHAIN029`	warning	Template expression in a dict key — only values are substituted, so the key is sent literally

Deep (opt-in) checks¶

HTTPCHAIN020–HTTPCHAIN024 come from deep validation (validate --deep), which imports your user modules and touches the filesystem — so it is opt-in and never runs at pytest collection time. Deep findings are always warnings; pair --deep with --strict to fail CI on them.

Filtering collection warnings¶

At collection time, warning-severity findings are emitted as pytest_httpchain.ScenarioValidationWarning (error-severity findings fail collection outright, and info findings — HTTPCHAIN025 — never affect validity, are exempt from --strict, and are not warned about at collection). Standard warning filters apply — e.g. to silence one code project-wide:

# pytest.ini
[pytest]
filterwarnings =
    ignore:.*HTTPCHAIN005.*:pytest_httpchain.ScenarioValidationWarning