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Upgrade a lazily-initialized @Nullable field to @MonotonicNonNull

io.moderne.nullability.infer.UpgradeLazilyInitializedFieldToMonotonicNonNull

Upgrades a private, non-final JSpecify @Nullable reference field to the Checker Framework @org.checkerframework.checker.nullness.qual.MonotonicNonNull annotation when it is genuinely a lazily-initialized-non-null field, so NullAway treats reads of it as non-null and the requireNonNull noise a plain @Nullable would force at every read disappears. A field qualifies only if it is private and non-final, its declaration declares exactly one reference-typed variable, there is at least one assignment to it, EVERY assignment has a provably-non-null right-hand side (new, an array creation, a non-null literal, this, or a call to a method whose return is resolved and not @Nullable), at least one assignment is outside a constructor (the lazy signal), and EVERY null-observation of the field (f == null/f != null/f instanceof X) is a lazy-init guard — the condition of an if whose then-branch assigns the field. Conservative and sound by design: private bounds the analysis to the declaring class so it is complete, and the absence of any null-handling use means the upgrade is runtime-NPE-preserving — it only removes the @Nullable signal where null would already crash. Any field whose null is handled gracefully anywhere, or any condition that cannot be proven, leaves the field unchanged. Only Java sources are modified.

Recipe source​

This recipe is only available to users of Moderne.

This recipe is available under the Moderne Proprietary License.

Used by​

This recipe is used as part of the following composite recipes:

Usage​

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 UpgradeLazilyInitializedFieldToMonotonicNonNull

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

mod config recipes jar install io.moderne.recipe:rewrite-nullability:0.1.0

See how this recipe works across multiple open-source repositories​

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Data Tables​

Source files that had results​

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column NameDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA 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 changesIn 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 changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.