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Add @Nullable to method parameters that can receive null

io.moderne.nullability.infer.AddNullableToParameterCrossFile

Adds the JSpecify @Nullable annotation to a Java method parameter when some call site anywhere in the project provably passes a nullable argument in that position: the null literal (directly, through a cast or parentheses, or via either branch of a ternary), or a call to a method whose return is itself nullable. Nullability therefore propagates from the call site to the callee's declaration across the whole project. This prepares the code for NullAway. Conservative by design: it skips primitive parameters, parameters that already carry a nullability annotation, varargs parameters, and @Override methods (where widening a parameter would break override consistency). Kotlin and Groovy express parameter nullability in the type system (T?), which the compiler already enforces, so those sources are generally left unchanged.

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​
class Test {
    void use(String name) {
    }

    void caller() {
        use(null);
    }
}
After​
import org.jspecify.annotations.Nullable;

class Test {
    void use(@Nullable String name) {
    }

    void caller() {
        use(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 AddNullableToParameterCrossFile

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.