Make a codebase null-safe

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.NullSafety

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

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

Options

Definition

This recipe runs the following recipes in order.

• Migrate @NonNullApi/ParametersAreNonnullByDefault to JSpecify @NullMarkedio.moderne.nullability.MigrateNonNullApiToNullMarked
• Add @NullMarked to every packageio.moderne.nullability.AddNullMarkedToAllPackages
• Compose JSpecify best practices (intra-body nullability inference)io.moderne.nullability.ComposeJSpecifyBestPractices
• Add @Nullable to methods that can return nullio.moderne.nullability.AddNullableToReturnType
• Add @Nullable to method parameters that can receive nullio.moderne.nullability.AddNullableToParameterCrossFile
• Add @Nullable to fields that can hold nullio.moderne.nullability.AddNullableToField
• Propagate @Nullable across override relationshipsio.moderne.nullability.PropagateNullableAcrossOverrides
• Add @Nullable to Java returns from Kotlin call sitesio.moderne.nullability.AddNullableFromKotlinCallSites
• Add @Nullable to array element types that can hold nullio.moderne.nullability.AddNullableToArrayElementType
• Add @Nullable to collection and map type arguments that hold null elementsio.moderne.nullability.AddNullableToTypeArgument
• Add a @Nullable upper bound to a pass-through type parameter fed a null-returning lambdaio.moderne.nullability.AddNullableBoundToPassthroughTypeParameter
• Add @Nullable to a functional-interface return type argument fed a null-returning lambdaio.moderne.nullability.AddNullableToFunctionalReturnArgument
• Remove a redundant declaration-position @Nullable on a method returnio.moderne.nullability.RemoveRedundantNullableOnMethodReturn
• Remove a redundant @NonNull annotation under @NullMarkedio.moderne.nullability.RemoveRedundantNonNullAnnotation
• Relocate a misplaced leading @Nullable on a primitive array to the array referenceio.moderne.nullability.RelocateNullableToArrayReference
• Move a leading @Nullable to the type-use positionio.moderne.nullability.MoveNullableToTypeUsePosition
• Replace @Nullable with @MonotonicNonNull on a lazily-initialized fieldio.moderne.nullability.ReplaceNullableWithMonotonicNonNullOnLazyField
• Hoist a guarded @Nullable field read into a local variableio.moderne.nullability.HoistNullableFieldReadIntoLocal
• Remove a provably-dead if (x == null) guardio.moderne.nullability.RemoveProvablyDeadNullGuard
• Add a @Contract nullness contract to a validation helperio.moderne.nullability.AddNullnessContractToValidationHelper
• Route a guarded raw accessor through its present Optionalio.moderne.nullability.CollapseOptionalPresentGuardToGet
• Extract a repeated @Nullable invocation into a local variableio.moderne.nullability.ExtractRepeatedNullableInvocationToLocal
• Replace nullable x.toString() with String.valueOf(x)io.moderne.nullability.ReplaceNullableToStringWithStringValueOf
• Make a nullable Boolean condition null-safe with Boolean.TRUE.equals(...)io.moderne.nullability.SafeNullableBooleanCondition
• Return an empty collection instead of nullio.moderne.nullability.ReturnEmptyCollectionInsteadOfNull
• Relax Optional.of to Optional.ofNullable on nullable valuesio.moderne.nullability.RelaxOptionalOfToOfNullable
• Add @MonotonicNonNull to an uninitialized fieldio.moderne.nullability.AddMonotonicNonNullToUninitializedField
• Align override nullability with the supertypeio.moderne.nullability.AlignOverrideNullabilityWithSupertype
• Wrap nullable arguments passed to non-null parameters in requireNonNullio.moderne.nullability.WrapNullableArgumentInRequireNonNull
• Wrap nullable dereferenced values in requireNonNullio.moderne.nullability.WrapNullableDereferenceInRequireNonNull
• Wrap nullable values that are auto-unboxed in requireNonNullio.moderne.nullability.WrapNullableUnboxingInRequireNonNull
• Wrap nullable switch selectors in requireNonNullio.moderne.nullability.WrapNullableSwitchSelectorInRequireNonNull
• Wrap a nullable for-each iterable in requireNonNullio.moderne.nullability.WrapNullableForEachIterableInRequireNonNull
• Wrap nullable thrown expressions in requireNonNullio.moderne.nullability.WrapNullableThrownExpressionInRequireNonNull
• Add @Nullable to a method that can return nullio.moderne.nullability.AddNullableToNullReturningMethod
• Add @Nullable to a field assigned a nullable valueio.moderne.nullability.AddNullableToNullAssignedField
• Add @Nullable to a mismatched generic type argumentio.moderne.nullability.AddNullableToMismatchedTypeArgument
• Move a leading @Nullable to the type-use positionio.moderne.nullability.MoveNullableToTypeUsePosition

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