v0.21.0

MINOR: before 1.0.0, a breaking change increases MINOR. typeFromSchema gives a narrower type for a schema with more than one of type, anyOf and oneOf. check finds more type issues. No export goes.

Changes of behavior

• typeFromSchema gives the meet of the keywords of a schema (D123). In 0.20.1, a schema with more than one of type, anyOf and oneOf gave the type of the first keyword, with an issue. This rule came from D28. In 0.21.0, the type is the meet of all the keywords. For example, {type:"number", anyOf:[{type:"string"}]} was number, and in 0.21.0 it is never. Each reading only narrows, and each reading stays sound.
• A step that reaches nothing in each run is a type issue (D120). In 0.20.1, some steps gave the type unknown with no issue. They are a field step on a kernel base type, a step on a function, and an unknown step on a list. In 0.21.0, check gives the issue of a missing field, as for a closed record (TYPE.NO-STEP).
• The reason of a missing field names a step document by its kind (D121). In 0.20.1, the reason showed [object Object] for a step document. In 0.21.0, it shows the kind in parentheses.

New features

• typeFromSchema reads local references and allOf (D123). A $ref to #/$defs/<name> or #/definitions/<name> reads that definition of the root schema. A reference to another file, a missing definition and a cycle of references read as unknown. The parts of allOf add their keywords to the schema.
• Collection attributes and a registry of names (D122). A declaration collect: { unit, combine } combines the contributions of a subtree. A kind contributes through its equation in tree.contributes. The form collect: "names" gives a registry from the header name of each node to its node. The new standard step tree.named reads the registry. Two nodes with one name give #VALUE! at the read of the registry. The new exports are CollectDeclaration, CollectRule and collectOf.
• A walker holds the type rule of its step (D121). A walker can hold an optional rule in its field type. The check then knows the type of what the walker reaches. A plain function stays a walker. The new export is WalkTypeInput.
• A kind declares the parts that its runner drives (D119). KindFacts gets the optional field drives. In a check of a run, a part that drives names gets no wait.
• The hook facts gives the effects of a code (D118). KindFacts gets the optional field effects. For the verb eval, the answer of the hook for the code wins over the contract. effectsOf, check and factsOf use that one declaration.

Tests and CI

These changes are not in the package. The margin and the noise cap of each case family of the bench come from the A/A records of CI (D117).