Configuration Precedence

This page defines the exact precedence used by ArgDigest.

Resolution order

ArgDigest resolves configuration from most specific to most general. Decorator arguments in @arg_digest(...) have highest priority. Then comes an explicit config= module/object, then environment configuration through ARGDIGEST_CONFIG, followed by auto-discovery of <root_package>._argdigest when no explicit config is provided. If none of that is available, ArgDigest uses global defaults from argdigest.config.set_defaults(...), and finally built-in defaults.

Practical examples

Example A: decorator override wins

@arg_digest(config="mylib._argdigest", strictness="error")
def get(...):
    ...

If mylib._argdigest sets STRICTNESS = "warn", the effective value is error.

Example B: explicit config beats auto-discovery

@arg_digest(config="mylib.custom_argdigest")
def get(...):
    ...

ArgDigest does not use <root_package>._argdigest for this function.

Example C: no explicit config

@arg_digest()
def get(...):
    ...

ArgDigest first checks ARGDIGEST_CONFIG, then tries <root_package>._argdigest. If unavailable, global defaults apply.

Recommendation

In production libraries, a good default is to keep most functions on @arg_digest(config="mylib._argdigest") and reserve decorator-level overrides for exceptional endpoints. Too many local overrides make behavior harder to reason about and slower to review.

Next

Continue with Digestion Styles.