Properties that are propagated to subschemas attached by composition should not be displayed

[pspot2]

Consider the following schema:

Click to expand

{
    "$id": "file:///home/eub-user/schema_test1.json",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "title": "root",
    "description": "Root-level schema",
    "type": "object",
    "required": [
        "test_property01"
    ],
    "properties": {
        "test_property01": {
            "description": "Test property 01",
            "enum": [
                "myvalue1",
                "myvalue2"
            ]
        }
    },
    "allOf": [
        {
            "if": {
                "properties": {
                    "test_property01": {
                        "const": "myvalue1"
                    }
                },
                "required": [
                    "test_property01"
                ]
            },
            "then": {
                "description": "TBD",
                "required": [
                    "test_propertyA"
                ],
                "additionalProperties": false,
                "properties": {
                    "test_property01": true,
                    "test_propertyA": {
                        "description": "Test property A",
                        "type": "string"
                    }
                }
            }
        },
        {
            "if": {
                "properties": {
                    "test_property01": {
                        "const": "myvalue2"
                    }
                },
                "required": [
                    "test_property01"
                ]
            },
            "then": {
                "description": "TBD",
                "required": [
                    "test_propertyB"
                ],
                "additionalProperties": false,
                "properties": {
                    "test_property01": true,
                    "test_propertyB": {
                        "description": "Test property B",
                        "type": "string"
                    }
                }
            }
        }
    ]
}

This schema defines one fixed property (test_property01) and then another property using conditional schema composition. The additional property depends on the value of test_property01:

• if test_property01 = "myvalue1", then the additional property test_propertyA is added
• if test_property01 = "myvalue2", then the additional property test_propertyB is added

Important additional constraint: no other properties are allowed in the whole schema. In other words, this schema will validate an instance in one of the following cases:

1. If test_property01 = "myvalue1", the instance contains only

   test_property01
test_propertyA

   and no other properties.

2. If test_property01 = "myvalue2", the instance contains only

   test_property01
test_propertyB

   and no other properties.

The constraint "no other properties" is achieved by adding additionalProperties: false to every conditional branch. In order for this to work, however, the existing property test_property01 must be "propagated" to every branch by adding it to the properties block of every branch as "test_property01": true.

Expectation: the property test_property01 is displayed only once in the rendered document. It is omitted from the list of properties in every allOf branch because it is already defined in the parent schema and is merely propagated from it.

Actual result: the rendered document displays the property test_property01 three times: once in the root schema and once in every allOf branch.

Click to expand

root

• Property root > allOf > item 0
  • If (test_property01 = "myvalue1")
    • Property root > allOf > item 0 > then > test_property01
    • Property root > allOf > item 0 > then > test_propertyA
• Property root > allOf > item 1
  • If (test_property01 = "myvalue2")
    • Property root > allOf > item 1 > then > test_property01
    • Property root > allOf > item 1 > then > test_propertyB
• Property root > test_property01

Title: root

Type	combining
Additional properties

Description: Root-level schema

Property	Pattern	Type	Deprecated	Definition	Title/Description
+ test_property01	No	enum (of string)	No	-	Test property 01

All of(Requirement)
item 0
item 1

Property root > allOf > item 0

Type	object
Additional properties

If (test_property01 = "myvalue1")

Type	object
Additional properties

Description: TBD

Property	Pattern	Type	Deprecated	Definition	Title/Description
- test_property01	No	object	No	-	-
+ test_propertyA	No	string	No	-	Test property A

Property root > allOf > item 0 > then > test_property01

Type	object
Additional properties

Property root > allOf > item 0 > then > test_propertyA

Type	string

Description: Test property A

Property root > allOf > item 1

Type	object
Additional properties

If (test_property01 = "myvalue2")

Type	object
Additional properties

Description: TBD

Property	Pattern	Type	Deprecated	Definition	Title/Description
- test_property01	No	object	No	-	-
+ test_propertyB	No	string	No	-	Test property B

Property root > allOf > item 1 > then > test_property01

Type	object
Additional properties

Property root > allOf > item 1 > then > test_propertyB

Type	string

Description: Test property B

Property root > test_property01

Type	enum (of string)

Description: Test property 01

Must be one of:

• "myvalue1"
• "myvalue2"

---

Generated using json-schema-for-humans on 2022-10-27 at 22:37:55 +0000

Note: the not-yet-supported unevaluatedProperties: false removes the need to propagate properties. However, in many cases the older construct presented above is more preferable because validators produce cleaner error messages (without any cascaded secondary errors).