Validation

The Gradle plugin defaults to KayanValidationMode.SUBSET. In subset mode, Kayan validates keys declared in the local schema and ignores undeclared keys, which lets several modules consume one shared config file.

The lower-level DefaultConfigResolver API defaults to strict validation unless you pass a KayanValidationMode explicitly. That keeps standalone resolver usage conservative while the Gradle plugin stays friendly to multi-module shared config.

Use KayanValidationMode.STRICT when a module owns the whole config file and unknown keys should fail the build:

kayan {
    validationMode.set(io.kayan.KayanValidationMode.STRICT)
}

Mode	Unknown keys	Best fit
SUBSET	Ignored unless declared in this module’s schema	Shared config files and multi-module builds
STRICT	Fail validation	Single-owner config files

Kayan fails the build when any of the following conditions are detected:

• flavors is missing or not an object — every config file must contain a flavors key with an object value
• Unknown keys in strict mode — a config contains a key not declared in the schema
• Type mismatches — a value does not match the declared schema type
• Unknown custom flavors — the custom config introduces a flavor missing from the base config
• Missing required values — a required key does not resolve for a flavor
• Blocked overrides — a custom config sets a key marked preventOverride

All validation errors include the source file, key path, and flavor name so you can find and fix the issue quickly.

For shared root schemas, see Multi-Module Shared Config.