Replace nullable x.toString() with String.valueOf(x)
io.moderne.nullability.ReplaceNullableToStringWithStringValueOfio.moderne.recipe:rewrite-nullabilityRewrites x.toString() to String.valueOf(x) when the receiver x is provably nullable at that site. x.toString() dereferences x and throws NullPointerException when x is null, which NullAway flags inside an annotated scope; String.valueOf(x) returns the string "null" instead. This is a behavior change on the null path (NullPointerException becomes the string "null"), so every rewritten call is marked for review — it is not behavior-preserving. Only the no-arg toString() whose receiver is a reference value is rewritten; a primitive receiver, a type or package qualifier, a .class literal, and this/super are never touched, and a receiver already asserted non-null is skipped. The receiver's nullness is resolved by attribution from the nullability model and a path-sensitive flow analysis (a value already null-checked on the path is not flagged). The fix never rewrites a call whose receiver is genuinely non-null at the site. Conservative; only Java sources are modified.
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.ReplaceNullableToStringWithStringValueOfIf the recipe isn’t available locally, install it with:
mod config recipes jar install io.moderne.recipe:rewrite-nullability:0.3.1Options
| 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