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Align override nullability with the supertype

Recipe IDio.moderne.nullability.AlignOverrideNullabilityWithSupertype
Artifactio.moderne.recipe:rewrite-nullability

Aligns a method or lambda parameter whose declared nullability is inconsistent with the supertype member it overrides, a contract violation under NullAway. An override that restricts a @Nullable supertype parameter to non-null has JSpecify @Nullable added to that parameter (parameters are contravariant); an override that widens a non-null supertype return to @Nullable has the erroneous @Nullable removed from its return type and its @Nullable returns wrapped in java.util.Objects.requireNonNull(...) (return types are covariant), which leaves runtime behavior unchanged. Conservative: a supertype's annotations are trusted only when the supertype is itself in an annotated scope, a return null and a null-guarded return are never wrapped, and nothing is changed when a participating type cannot be resolved. Idempotent; Java sources only.

Single recipeProprietary

Usage

This recipe has no required configuration options. You’ll need the Moderne CLI configured before running the command below.

mod run . --recipe io.moderne.nullability.AlignOverrideNullabilityWithSupertype

If the recipe isn’t available locally, install it with:

mod config recipes jar install io.moderne.recipe:rewrite-nullability:0.3.1

Options

NameTypeDescription
annotatedPackagesStringComma-separated package prefixes to limit the fix to (matching NullAway's AnnotatedPackages option). When unset, the recipe fixes all packages.
e.g. com.example

Data tables

Structured output this recipe can produce.

  • Null-safety fixes by rungEach residual null-safety fix applied, tagged with the precedence rung that produced it, so the share bottoming out at a last-resort `requireNonNull` assertion can be tracked.io.moderne.nullability.table.NullFixes
  • Declined null-safety fixes needing reviewEach site the recipe declined to auto-fix because the fix is a design decision (the value is explicitly `null` on some path, so the slot likely should be `@Nullable`), for human triage.io.moderne.nullability.table.DeclinedNullFixes
  • Source files that had resultsSource files that were modified by the recipe run.org.openrewrite.table.SourcesFileResults
  • Source files that had search resultsSearch results that were found during the recipe run.org.openrewrite.table.SearchResults
  • Source files that errored on a recipeThe details of all errors produced by a recipe run.org.openrewrite.table.SourcesFileErrors
  • Recipe performanceStatistics used in analyzing the performance of recipes.org.openrewrite.table.RecipeRunStats