Moderne licensed

Remove a provably-dead `if (x == null)` guard

Recipe IDio.moderne.nullability.RemoveProvablyDeadNullGuardArtifactio.moderne.recipe:rewrite-nullability

Removes an if (x == null) { ... } guard whose then-branch the flow engine proves unreachable because x is already non-null at that point (e.g. after an earlier assertion, guard, or assignment). Such a guard is dead code: the x == null test can never be true, so its then-branch never executes and deleting it — while keeping any else body, the only live path — preserves behavior. To match the aggressiveness Airbnb endorses and no further, the removal fires only when the path-sensitive flow analysis decisively proves x non-null at the guard, and never on a parameter of a public method (the service-edge / untrusted-input validation point NullAway guidance explicitly excludes). The condition must be a bare x == null / null == x on a simple local or parameter; a compound condition, a field, or anything not flow-proven is left untouched. Behavior-preserving (it removes only unreachable code), idempotent, and conservative; only Java sources are modified.

Single recipeProprietary

Add to your build

Get a download tokenThis recipe is Moderne licensed, so the token must belong to a Moderne customer. It replaces YOUR_DOWNLOAD_TOKEN below.

~/.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.RemoveProvablyDeadNullGuard")
}

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 rewriteRun

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.RemoveProvablyDeadNullGuard

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

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

Options

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