avro schema compatibility derived

{
  "input": {
    "body": {
      "after": {
        "name": "Order",
        "type": "record",
        "fields": [
          {
            "name": "order_id",
            "type": "string"
          },
          {
            "name": "total_cents",
            "type": "int"
          },
          {
            "name": "status",
            "type": {
              "name": "Status",
              "type": "enum",
              "symbols": [
                "OPEN"
              ]
            }
          },
          {
            "name": "note",
            "type": [
              "null",
              "string"
            ],
            "default": null
          },
          {
            "name": "channel",
            "type": "string"
          }
        ],
        "namespace": "shop.v1"
      },
      "before": {
        "name": "Order",
        "type": "record",
        "fields": [
          {
            "name": "order_id",
            "type": "string"
          },
          {
            "name": "total_cents",
            "type": "long"
          },
          {
            "name": "status",
            "type": {
              "name": "Status",
              "type": "enum",
              "symbols": [
                "OPEN",
                "CLOSED"
              ]
            }
          },
          {
            "name": "note",
            "type": [
              "null",
              "string"
            ],
            "default": null
          }
        ],
        "namespace": "shop.v1"
      }
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "limits": {
        "maxFindings": 500,
        "maxSdlBytes": 262144,
        "maxVersions": 25,
        "maxAvroBytes": 262144,
        "maxConsumers": 50,
        "maxProtoBytes": 262144,
        "maxPathsPerConsumer": 200
      },
      "passed": false,
      "complete": true,
      "findings": [
        {
          "code": "TYPE_NOT_PROMOTABLE",
          "detail": "Reading old data with the new schema: The writer writes long and the reader expects int, which is not a permitted promotion.",
          "location": ".total_cents",
          "direction": "backward"
        },
        {
          "code": "ENUM_SYMBOL_NOT_READABLE",
          "detail": "Reading old data with the new schema: The writer may write CLOSED and the reader has no such symbol and no enum default to fall back to.",
          "location": ".status",
          "direction": "backward"
        },
        {
          "code": "READER_FIELD_HAS_NO_DEFAULT",
          "detail": "Reading old data with the new schema: The reader expects channel, the writer does not write it, and it declares no default, so the reader cannot fill it.",
          "location": "(root).channel",
          "direction": "backward"
        }
      ],
      "after_root": "record shop.v1.Order",
      "compatible": false,
      "request_id": "example-request",
      "service_id": "avro_schema_compatibility",
      "assumptions": [
        "Backward means a reader on the new schema can read data already written with the old one. Forward means a reader still on the old schema can read data written with the new one. Both are reported, beca...",
        "Resolution follows the Avro rules rather than a structural comparison: fields match by name with the reader aliases consulted, int promotes to long, float and double one way only, a reader field absen...",
        "Nothing is fetched. No registry is consulted, so a subject name, a registered version or a registry-level compatibility setting plays no part."
      ],
      "before_root": "record shop.v1.Order",
      "limitations": [
        "Whether the resolution rules permit the pair of schemas supplied. Whether application code handles a defaulted field sensibly is outside this.",
        "compatible is true only when both directions resolve cleanly. The two directional flags are published separately so a caller enforcing only one can read it."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "finding_count": 3,
      "service_version": "1.0.0",
      "after_node_count": 8,
      "findings_by_code": {
        "TYPE_NOT_PROMOTABLE": 1,
        "ENUM_SYMBOL_NOT_READABLE": 1,
        "READER_FIELD_HAS_NO_DEFAULT": 1
      },
      "before_node_count": 7,
      "forward_compatible": true,
      "backward_compatible": false,
      "forward_finding_count": 0,
      "backward_finding_count": 3
    }
  }
}