changes method
Declares how this project's changes should be ranked. See ChangesConfig.
Refused twice rather than merged or overwritten. Two calls would be a config with two answers, and either resolution loses one of them silently — which is the failure mode that killed the standalone package list.
Implementation
void changes(ChangesConfig config) {
if (_changes != null) {
throw StateError(
'fw.changes was called twice. Declare one ChangesConfig with every '
'pattern in it.',
);
}
_changes = config;
}