generate method
String?
generate(
- LibraryReader library,
- BuildStep? buildStep, {
- Schema? newSchema,
- int? version,
Creates a new migration from the delta between the existing migration and a new schema
Implementation
@override
String? generate(library, BuildStep? buildStep, {Schema? newSchema, int? version}) {
final allMigrations = expandAllMigrations(library);
final oldSchema = Schema.fromMigrations(allMigrations.toSet());
final difference = newSchema == null
? SchemaDifference(emptySchema, oldSchema)
: SchemaDifference(oldSchema, newSchema);
if (!difference.hasDifference || difference.toMigrationCommands().isEmpty) {
return null;
}
final output = Migration.generate(difference.toMigrationCommands(), version!);
return output;
}