Fix bug in ModelUtils.getParentName resulting in wrong inner Models for oneOf-composed schemas

[fkellner]

The ModelUtils.getParentName function description states:

If there are multiple elements in the composed schema and it is not clear which one should be the parent, return null.

It returned the first parent candidate instead. This resulted in a weird bug where generated client models did not contain all fields of their subschemas mentioned in oneOf (fixes #21773 , in particular this affects at least Java Microprofile and Vertx generators).

This PR contains some new tests:

• one regression test for the fixed function (in ModelUtilsTest)
• one test case with the (simplified) spec that discovered the bug in JavaCodegenTest (and also in DefaultCodegenTest to narrow it down)

Also, the oneOf-Test was changed to contain three schemas, because at first I thought the issue was with the number of schemas and in general it is probably better to test something accepting a list with three instead of two elements.

Running the scripts to update samples and docs did not change anything (as was to be expected).

Please tell me if I should

• rebase this onto latest master
• squash the commits
• rename the example yaml to something different

Also, since I found this mostly via debugging and am not proficient with the terminology and edge cases of this project, my fix follows the philosophy to touch/change as little as possible, however, somebody with more experience than me might want to clean up that function since there seems to be some unreachable/unused code according to my IDE.

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@bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608 @martin-mfg

[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/OpenAPITools/openapi-generator/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/OpenAPITools/openapi-generator/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account

[fkellner]

Thank you very much, adding the email address fixed it!

[fkellner]

since there was a failing check that is probably due to the branch being based on an outdated master, I synced the branch.

[wing328]

please

• merge the latest master into your branch and resolve the merge conflicts
• update the samples

then i will try to test your fix before merging

[wing328]

https://github.com/OpenAPITools/openapi-generator/actions/runs/17371620947/job/49309557740?pr=21799

please run the command to update the samples one more time

[wing328]

did a test locally and all tests passed

#21859

[wing328]

we will later revise the test instead if it still occurs after merging into master

thanks for the PR to fix the bug

[wing328]

update: merged #21865 to disable the tests (which only failed in Windows but not Linux)