kspDeclarationSnapshot

Whether the test source set's KSP run reads a declarations-only snapshot of the main classes — and of the other modules of this build it depends on — instead of the classes themselves. On by default. Applies to JVM targets.

The registry depends on the fixtures and on what their declarations say, never on a function body. KSP cannot tell the two apart: it re-runs on any change to a class on its classpath, and with Compose that is almost every edit — the compiler records each composable's source offsets in @FunctionKeyMeta, so retyping one string literal changes every composable after it in the file. The snapshot drops bodies, debug information and those offsets, and is rewritten only when a declaration changes, so editing a component no longer re-runs KSP over every fixture. A module that holds only fixtures and draws components from sibling modules gets the same through an artifact transform over those modules' jars and class directories.

Measured on a module of 1000 fixtures: editing a component and recording one golden went from ~4.1 s to ~3.0 s, of which KSP had been ~0.8 s. Turn it off if a processor in the same KSP run needs to see main classes as they are rather than their declarations — none of viddik's does.