[Bug]: Incorrect PATCH request schema

[markcowl]

Describe the bug

The OpenAPI3 emitter will put readOnly properties into the PATCH request schema, provided all properties are optional as in this playground

However, it does create separate schema omitting the read-only property as expected, if this (or any) property is marked required as in this playground

Reproduction

Playground showing read-only property in patch input schema

Playground showing a required property creatign a new schema removing the read-only property

Checklist

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.

[markcowl]

This is by design - readOnly properties can be safely shared between input and output schema, and we correctly treat "create", "read" visibility in this case.