Description disappears from the generated json after upgrade to 3.0.3

[petergphillips]

Describe the bug
After the upgrade from springdoc 3.0.2 to 3.0.3 we've noticed that

  @field:Schema(description = "The object of the person to greet")
  val objectName: SomeObject? = null,

gets generated as

          "objectName" : {
            "oneOf" : [ {
              "$ref" : "#/components/schemas/SomeObject"
            }, {
              "type" : "null"
            } ]
          }

and the description is then not set at all.

Under springdoc 3.0.2 the same code generated:

          "objectName" : {
            "$ref" : "#/components/schemas/SomeObject",
            "description" : "The object of the person to greet"
          }

To Reproduce

• What version of spring-boot you are using? 4.0.5
• What version of kotlin are you using? 2.3.20
• What modules and versions of springdoc-openapi are you using? 3.0.3
• What is the actual and the expected result using OpenAPI Description (yml or json)? See above for actual and also the generated code in 3.0.2. I would expect the description to be still set.
• Provide with a sample code (HelloController) or Test that reproduces the problem

@RestController
class IssuesController {
  @GetMapping("/")
  fun greet(greeting: Greeting): String = greeting.objectName?.toString() ?: "Hello World"
}

data class Greeting(
  @field:Schema(description = "The object of the person to greet")
  val objectName: SomeObject? = null,
)
data class SomeObject(val someProperty: String)

Expected behavior
The description is generated and not missing.

Note that if the field is defined as

  val stringName: String? = null,

then the generated code is

          "stringName" : {
            "type" : [ "string", "null" ],
            "description" : "The name of the person to greet"
          },

[petergphillips]

See https://github.com/petergphillips/springdoc-issues/blob/pgp-springdoc-3274/README.md for a sample project and test demonstrating the issue.

[petergphillips]

Also just discovered that deprecated disappears as well. So:

  @Deprecated("Use stringName instead")
  val objectName: SomeObject? = null,

used to generate

          "objectName" : {
            "$ref" : "#/components/schemas/SomeObject",
            "deprecated" : true,
          }

and now just generates

          "objectName" : {
            "oneOf" : [ {
              "$ref" : "#/components/schemas/SomeObject"
            }, {
              "type" : "null"
            } ]
          }

[Mattias-Sehlstedt]

Most likely that #3256 forgot to consider sibling properties. The change will be reverted #3276.