Rules reference¶

dddlint emits two families of findings: code rules against your source, and config rules against dddlint.yaml itself. Every finding has a rule name, a severity, and a message.

Code rules¶

Checked against the definition names (classes, functions, methods, structs, interfaces, enums, traits, variables, constants) extracted from your source.

forbidden¶

Severity: error. A definition name contains a banned term from forbidden.

Names are tokenised on case and separator boundaries before matching, so OrderManager contains the token manager.

from pathlib import Path

from dddlint.check import check
from dddlint.config import Config
from dddlint.extract import Definition

config = Config(forbidden=["manager"])
defs = [Definition("OrderManager", "Class", Path("orders.py"), 1)]

findings = check(defs, config)

assert findings[0].rule == "forbidden"
assert "manager" in findings[0].message

alias¶

Severity: warning. A definition uses a non-canonical synonym. The finding carries a fix — the name rewritten to the canonical term with case preserved. Emitted only when enforce_canonical is true.

from pathlib import Path

from dddlint.check import check
from dddlint.config import Config, SynonymGroup
from dddlint.extract import Definition

config = Config(synonyms=[SynonymGroup(canonical="customer", aliases=["client"])])
defs = [Definition("ClientRepository", "Class", Path("repo.py"), 1)]

alias = next(f for f in check(defs, config) if f.rule == "alias")

assert alias.fix == "CustomerRepository"
assert "customer" in alias.message

drift¶

Severity: info. The same concept is spelled several different ways across the codebase. Two names drift together when they tokenise to the same set of tokens, regardless of order or casing.

from pathlib import Path

from dddlint.check import check
from dddlint.config import Config
from dddlint.extract import Definition

defs = [
    Definition("get_user_by_id", "Function", Path("a.py"), 1),
    Definition("getUserById", "Function", Path("b.py"), 1),
]

rules = {f.rule for f in check(defs, Config())}

assert "drift" in rules

Config rules¶

Checked against dddlint.yaml on every run so a broken vocabulary is caught before it hides real findings.

Rule	Severity	Description
`config:forbidden-canonical-clash`	error	A term is both `forbidden` and a canonical synonym
`config:alias-conflict`	warning	The same alias maps to different canonicals in different scopes
`config:duplicate-name`	info	Two domains or contexts have names more similar than `similarity_threshold`

from pathlib import Path

from dddlint.config import Config, SynonymGroup
from dddlint.config_check import check_config

config = Config(
    forbidden=["order"],
    synonyms=[SynonymGroup(canonical="order", aliases=["purchase"])],
)

findings = check_config(config, Path("dddlint.yaml"))
rules = {f.rule for f in findings}

assert "config:forbidden-canonical-clash" in rules