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Propagate @Nullable across override relationships

io.moderne.nullability.infer.PropagateNullableAcrossOverrides

Enforces NullAway override consistency by propagating existing JSpecify @Nullable annotations through @Override relationships. Because return types are covariant, a @Nullable return on an overriding method is propagated up to the supertype method it overrides. Because parameters are contravariant, a @Nullable parameter on a supertype method is propagated down to the corresponding parameter of every overriding method. Methods are matched across files by their erased signature name(paramTypes) plus a declaring-type subtype relationship. Conservative by design: it never widens a legal covariant return narrowing (a @Nullable supertype return overridden by a non-null return is left alone), skips primitive and void returns and already-annotated positions, and does nothing when a participating type cannot be resolved. Multi-hop hierarchies converge over successive recipe cycles. Only Java sources are modified; Kotlin and Groovy express nullability in the type system, which their compilers already enforce.

Recipe source​

This recipe is only available to users of Moderne.

This recipe is available under the Moderne Proprietary License.

Used by​

This recipe is used as part of the following composite recipes:

Example​

Before​
interface Service {
    String find();
}
After​
import org.jspecify.annotations.Nullable;

interface Service {
    @Nullable
    String find();
}
Unchanged​
import org.jspecify.annotations.Nullable;

class ServiceImpl implements Service {
    @Override
    public @Nullable String find() {
        return null;
    }
}

Usage​

This recipe has no required configuration options. Users of Moderne can run it via the Moderne CLI.

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell
mod run . --recipe PropagateNullableAcrossOverrides

If the recipe is not available locally, then you can install it using:

mod config recipes jar install io.moderne.recipe:rewrite-nullability:0.1.0

See how this recipe works across multiple open-source repositories​

Run this recipe on OSS repos at scale with the Moderne SaaS.

The community edition of the Moderne platform enables you to easily run recipes across thousands of open-source repositories.

Please contact Moderne for more information about safely running the recipes on your own codebase in a private SaaS.

Data Tables​

Source files that had results​

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column NameDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changesIn a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.