Breaking change not detected when type changes for dictionary value object

[shahakL]

Describe the bug
Comparing the following 2 OpenAPI schemas:

{
  "components": {
    "schemas": {
      "Schema1": {
        "properties": {
          "property1": {
            "title": "Value",
            "type": "integer"
          }
        },
        "type": "object"
      },
      "Schema2": {
        "properties": {
          "composite-property": {
            "additionalProperties": {
              "$ref": "#/components/schemas/Schema1"
            },
            "title": "Composite",
            "type": "object"
          }
        },
        "type": "object"
      }
    }
  },
  "paths": {
    "/value": {
      "get": {
        "operationId": "get_value",
        "responses": {
          "200": {
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Schema2"
                }
              }
            },
            "description": "Successful Response"
          }
        }
      }
    }
  }
}

And:

{
  "components": {
    "schemas": {
      "Schema1": {
        "properties": {
          "property1": {
            "title": "Value",
            "type": "string"
          }
        },
        "type": "object"
      },
      "Schema2": {
        "properties": {
          "composite-property": {
            "additionalProperties": {
              "$ref": "#/components/schemas/Schema1"
            },
            "title": "Composite",
            "type": "object"
          }
        },
        "type": "object"
      }
    }
  },
  "paths": {
    "/value": {
      "get": {
        "operationId": "get_value",
        "responses": {
          "200": {
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Schema2"
                }
              }
            },
            "description": "Successful Response"
          }
        }
      }
    }
  }
}

The only change is for the inner object Schema1, where its property changed from integer to string. This should be considered a breaking change, however oasdiff ignores the change completely.
When changing the return schema from Schema2 to Schema1, the change is detected and reported as breaking as it should.

To Reproduce
Steps to reproduce the behavior:

1. Copy the 2 OpenAPI schemas above to files spec1.json and spec2.json
2. oasdiff breaking spec1.json spec2.json
3. Output is empty

Expected behavior
Correct output should be the same when changing the response schema to schema1:

error   [response-property-type-changed] at spec2.json
        in API GET /value
                the 'property1' response's property type/format changed from 'string'/'' to 'integer'/'' for status '200'

Desktop (please complete the following information):

• OS: macos 14.6.1
• oasdiff version 1.10.23

[reuvenharrison]

This is due to additionalProperties which is used in Schema2.
Oasdiff doesn't currently support breaking changes for additionalProperties.

I am going to change this issue type from a bug to an enhancement to remind myself or another kind contributor to add support for additionalProperties.

[shahakL]

Thank you @reuvenharrison !