Issue 22784

[kingofdisasterr]

fixes #22784

@cachescrubber @welshm @MelleD @atextor @manedev79 @javisst @borsch @banlevente @Zomzog @martin-mfg

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Summary by cubic

Generate optional arrays with minItems > 0 as null in Java models instead of defaulting to empty lists. This prevents empty arrays that violate minItems and aligns the Java/Spring codegen with the OpenAPI spec. Fixes #22784.

• Bug Fixes
  • Optional array properties with minItems > 0 now generate as uninitialized (@nullable List) rather than new ArrayList<>().
  • Added OpenAPI 3.1 sample and SpringCodegen test to verify the behavior.
  • Updated petstore sample (AnyTypeTest) to remove default empty list initialization.

^{Written for commit 92c4bc0. Summary will update on new commits.}

[kingofdisasterr]

@wing328 i had to open a new PR since i messed up with this one: #22794

[cubic-dev-ai]

No issues found across 5 files

[cubic-dev-ai]

No issues found across 5 files

[Chrimle]

Separate to a new if below. With the inlined comment. (Potentially also the Issue-Id #?)

[MelleD]

You cannot change the default for everyone. Some people do not have nulls in their projects. That is why you need to consider the containerDefaultToNull property.

Furthermore, I am convinced that you can easily implement your plan with a change in the open API spec.

You either have to use minItems with a required property (which makes more sense in my opinion) or you have to set minItems and nullable: true, then a null array should also be generated.

The last and simplest option is to use containerDefaultToNull and if something doesn't work there, fix this.

Optional arrays do NOT have to be null.
Depending on how you set up your ObjectMapper, empty arrays are also optional values. Perhaps this is also an option for you. There are many good descriptions of why null arrays and empty arrays have the same semantic meaning in REST API. Normally, you don't need more than 2 states in REST API (except for patch).