[BUG][kotlin-spring] missing JsonInclude import for optional+nullable-only models when using jsonNullable

[Picazsoo]

fixes #24365

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---

Summary by cubic

Fixes missing com.fasterxml.jackson.annotation.JsonInclude import in Kotlin Spring models whose only field is optional + nullable when jsonNullable is enabled, preventing compile errors from @field:JsonInclude(NON_ABSENT). Also ensures org.openapitools.jackson.nullable.JsonNullable is imported only when nullable fields are present.

• Bug Fixes
  • Kotlin Spring: add JsonInclude to model imports when openApiNullable=true and a property is optional + nullable (including optional+nullable-only models).
  • Spring generators: add JsonNullable import whenever a property is nullable and remove the unconditional import from JavaSpring/model.mustache.
  • Add regression test and minimal spec for the optional-nullable-only case; update petstore YAML and generated samples, removing unused JsonNullable imports.

^{Written for commit ee2e636. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 12 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/OptionalNullableOnlyModel.java">

<violation number="1" location="samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/OptionalNullableOnlyModel.java:10">
P3: Duplicate `JsonNullable` import in the generated Java model. The import `org.openapitools.jackson.nullable.JsonNullable` appears twice (lines 12 and 19). While Java permits duplicate imports without a compilation error, this dead import is unnecessary and suggests the generator's import-dedup logic can produce a double entry when both the main code path and the `JsonInclude`-fix path independently add the same import. Removing the second occurrence keeps the generated code clean.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P3: Duplicate JsonNullable import in the generated Java model. The import org.openapitools.jackson.nullable.JsonNullable appears twice (lines 12 and 19). While Java permits duplicate imports without a compilation error, this dead import is unnecessary and suggests the generator's import-dedup logic can produce a double entry when both the main code path and the JsonInclude-fix path independently add the same import. Removing the second occurrence keeps the generated code clean.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/OptionalNullableOnlyModel.java, line 10:

<comment>Duplicate `JsonNullable` import in the generated Java model. The import `org.openapitools.jackson.nullable.JsonNullable` appears twice (lines 12 and 19). While Java permits duplicate imports without a compilation error, this dead import is unnecessary and suggests the generator's import-dedup logic can produce a double entry when both the main code path and the `JsonInclude`-fix path independently add the same import. Removing the second occurrence keeps the generated code clean.</comment>

<file context>
@@ -0,0 +1,99 @@
+import com.fasterxml.jackson.annotation.JsonCreator;
+import java.util.Arrays;
+import java.util.UUID;
+import org.openapitools.jackson.nullable.JsonNullable;
+import org.springframework.lang.Nullable;
+import java.util.NoSuchElementException;
</file context>

[Picazsoo]

This is existing issue. I will eventually fix it, but I want to focus on the core issue here

[wing328]

for duplicate import, i think we can create a lambda to remove duplicated lines in a text block. not the best approach but i think it should work.

[Picazsoo]

I can fix the root cause in this case. It is just that this very PR fixes very similar oversight where the import was not added at all. I am worried that I might introduce another regression. But I will take a stab at it.

[Picazsoo]

I fixed the issue with the duplicate JsonNullable import. It was removed from A LOT of samples.

[Picazsoo]

So in general @wing328 , I think this can be merged whenever you feel like it.

[cubic-dev-ai]

No issues found across 1560 files

<sub>Note: This PR contains a large number of files. cubic only reviews up to 200 files per PR, so some files may not have been reviewed. cubic prioritizes the most important files to review.

Re-trigger cubic</sub>