Same spec renders differently between this repos demo directory and a fresh install

[omonk]

Describe the bug

A developer raised an issue where a spec was rendering incorrectly. After debugging it I copied the same structure over to the demo repo and found that it renders as expected.

Wanting to ensure that our documentation repo wasn't the issue I created a fresh docusaurus project and added the docusaurus-plugin-openapi-docs package and recreated the setup from the docs repo

Reproduction repo - https://github.com/omonk/openapi-complex-test

Repo	Working
docusaurus-plugin-openapi-docs	🟢
Test repo	🔴
My work repo	🔴

Expected behavior

The schema has a oneOf where each property is an object marked as required.

When selecting the oneOf schemas tabs, all properties should visible and remain static, the only difference is that the required flag should move between them.

Screenshots below are my custom spec rendered in the tests directory of the demo repo. Note that required flag moves between identifier and bankIdentifier

Current behavior

With the same schema rendered in a fresh install you can see the properties are duplicated and when selecting the different tabs the top property differs. Note that identifier and bankIdentifier and duplicated in the schema

Possible solution

Unsure

Steps to reproduce

Reproduce on this demo repo

1. Copy complex.yam into demo/examples/tests/complex.yml
2. yarn build && yarn clean-api-docs tests && yarn gen-api-docs tests
3. yarn start
4. Navigate to http://localhost:3000/tests/complex-one-of

Reproduce on provided repo

1. Clone repo https://github.com/omonk/openapi-complex-test
2. npm i && npm run re-gen && npm run start
3. Navigate to http://localhost:3000/docs/complex/complex-one-of
4. Click between tabs, see that this is different

Screenshots

See above

Context

This incorrectly renders schemas to our users

Your Environment

• Version used: 5.0.2
• Environment name and version (e.g. Chrome 59, node.js 5.4, python 3.7.3): Chrome 148, node 24.14.1
• Operating System and version (desktop or mobile): macOS
• Link to your project: https://github.com/omonk/openapi-complex-test

[sserrata]

Thanks for the detailed report and reproducer — the matrix was the clue.

Root cause: when an object schema has oneOf and sibling properties, v5.0.2's renderer emits the sibling properties block once at the top and also emits each branch's properties inside its tab. For your spec, identifier and bankIdentifier exist both at the parent level and inside each oneOf branch, so they render twice.

Why the repo's demo/ works but a fresh v5.0.2 install doesn't: the fix already landed on main in c33fb913 (originally for #1218). It adds a foldSiblingsIntoBranches() step that merges the parent siblings into each branch via allOf-merge before rendering, so each tab shows the full property set once with only the required flag flipping — exactly what your "expected" screenshots show. The demo/ runs against main, so it picks up the fix; a fresh npm i docusaurus-plugin-openapi-docs@5.0.2 does not.

Verify ahead of the next release: the latest canary on npm includes the fix. You can try it with:

npm i docusaurus-plugin-openapi-docs@canary docusaurus-theme-openapi-docs@canary

(currently resolves to 0.0.0-1295, which is post-fix.)

I'd suggest closing this as resolved by #1457 once you've confirmed against the canary — happy to leave it open until then.