Align override nullability with the supertype
io.moderne.nullability.AlignOverrideNullabilityWithSupertypeArtifactio.moderne.recipe:rewrite-nullabilityAligns 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.
Add to your build
~/.gradle/gradle.properties
codeGenomeUsername=you@example.com
codeGenomeToken=YOUR_DOWNLOAD_TOKEN
build.gradle.kts
plugins {
id("org.openrewrite.rewrite") version("latest.release")
}
rewrite {
activeRecipe("io.moderne.nullability.AlignOverrideNullabilityWithSupertype")
}
repositories {
mavenCentral()
maven {
url = uri("https://artifacts.codegenomeproject.org/maven")
credentials {
username = providers.gradleProperty("codeGenomeUsername").get()
password = providers.gradleProperty("codeGenomeToken").get()
}
}
}
dependencies {
rewrite("io.moderne.recipe:rewrite-nullability:0.6.0")
}
Then run
./gradlew rewriteRunUsage
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.AlignOverrideNullabilityWithSupertypeIf the recipe isn’t available locally, install it with:
mod config recipes jar install io.moderne.recipe:rewrite-nullability:RELEASEOptions
| Name | Type | Description |
|---|---|---|
annotatedPackages | String | Comma-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