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Wrap nullable thrown expressions in requireNonNull

Recipe IDio.moderne.nullability.WrapNullableThrownExpressionInRequireNonNull

Artifactio.moderne.recipe:rewrite-nullability

Wraps a provably-nullable throw operand in java.util.Objects.requireNonNull(...) (statically imported), turning throw ex; into throw requireNonNull(ex);. A throw of a null Throwable itself throws NullPointerException (the JVM dereferences the operand to raise it), so inside an annotated scope NullAway flags a nullable thrown value as an error; requireNonNull throws exactly where the bare throw already would, so runtime behavior is unchanged. The operand'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 asserts non-null on a value that is genuinely nullable at the site. Idempotent and conservative; only Java sources are modified.

Single recipeOpenRewriteModerne Proprietary License

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Options

2 parameters

2 optional

Parameter	Example	Type	Required
annotatedPackages	com.example	String	Optional
Comma-separated package prefixes to limit the fix to (matching NullAway's AnnotatedPackages option). When unset, the recipe fixes all packages.
assertionStyle	—	AssertionStyle	Optional
The non-null assertion form to emit at a wrap site. AUTO (the default) inspects the classpath: Guava present (com.google.common) emits Preconditions.checkNotNull, otherwise Objects.requireNonNull. CAST_TO_NON_NULL is explicit-only (it is suppression-like — no runtime throw) and never auto-selected.

Usage

Run this recipe

This recipe has no required configuration options. Users of Moderne can run it via the Moderne CLI.

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell

mod run . --recipe WrapNullableThrownExpressionInRequireNonNull

If the recipe is not available locally, then you can install it using:

mod config recipes jar install io.moderne.recipe:rewrite-nullability:0.3.0

Data tables

Null-safety fixes by rung

io.moderne.nullability.table.NullFixes

Each 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.

Column	Description
Source path	The path of the source file that was fixed.
Recipe name	The name of the recipe that applied the fix.
Rung	The precedence rung that produced the fix (INFER, PLACE, RESTRUCTURE, GRACEFUL_NULL, or ASSERT_NON_NULL). ASSERT_NON_NULL is the last resort; the others are progressively more sophisticated transformations that avoid it.
Rung ordinal	The rung's position in the precedence ladder (0 = most sophisticated, 4 = the last-resort ASSERT_NON_NULL). A numeric sort key for ordering fixes by rung in a BI system.
Behavior changing	Whether the fix alters observable runtime behavior on the null path. True only for GRACEFUL_NULL fixes (which also carry a behavior-change marker); every other rung is behavior-preserving, including the ASSERT_NON_NULL requireNonNull wrap.

Declined null-safety fixes needing review

io.moderne.nullability.table.DeclinedNullFixes

Each 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.

Column	Description
Source path	The path of the source file containing the declined site.
Recipe name	The name of the recipe that declined the fix.
Reason	Why the fix was declined (e.g. EXPLICIT_NULL: the value is explicitly null on some path, so wrapping it would throw rather than assert).
Detail	A human-readable description of the declined site and the design decision it needs.

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column	Description
Source path before the run	The source path of the file before the run. null when a source file was created during the run.
Source path after the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changes	In a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changes	The specific recipe that made a change.
Estimated time saving	An estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
Cycle	The recipe cycle in which the change was made.

Source files that had search results

org.openrewrite.table.SearchResults

Search results that were found during the recipe run.

Column	Description
Source path of search result before the run	The source path of the file with the search result markers present.
Source path of search result after run the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Result	The trimmed printed tree of the LST element that the marker is attached to.
Description	The content of the description of the marker.
Recipe that added the search marker	The specific recipe that added the Search marker.

Source files that errored on a recipe

org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

Column	Description
Source path	The file that failed to parse.
Recipe that made changes	The specific recipe that made a change.
Stack trace	The stack trace of the failure.

Recipe performance

org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

Column	Description
The recipe	The recipe whose stats are being measured both individually and cumulatively.
Source file count	The number of source files the recipe ran over.
Source file changed count	The number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time (ns)	The total time spent across the scanning phase of this recipe.
Max scanning time (ns)	The max time scanning any one source file.
Cumulative edit time (ns)	The total time spent across the editing phase of this recipe.
Max edit time (ns)	The max time editing any one source file.