Add "$ref" for subschemas to meta-schemas.

This ensures that subschemas are either "normal" JSON Schema
objects according to the declared vocabulary, or references.

The separate definitions of jsonReference and notJsonReference
ensure that objects with a "$ref" property that is not a URI
reference fail validation.  If we just negated the jsonReference
defintion, then {"$ref": 4} would validate as a non-reference
schema which is incorrect.

Author: handrews

draft-05/hyper-schema

@@ -5,7 +5,7 @@
     "definitions": {
         "schemaArray": {
             "type": "array",
-            "items": { "$ref": "#" }
+            "items": { "$ref": "#/definitions/subSchema" }
         },
         "linkDescription": {
             "title": "Link Description Object",
@@ -26,7 +26,7 @@
                 },
                 "targetSchema": {
                     "description": "JSON Schema describing the link target",
-                    "allOf": [ { "$ref": "#" } ]
+                    "allOf": [ { "$ref": "#/definitions/subSchema" } ]
                 },
                 "mediaType": {
                     "description": "media type (as defined by RFC 2046) describing the link target",
@@ -43,52 +43,64 @@
                 },
                 "schema": {
                     "description": "Schema describing the data to submit along with the request",
-                    "allOf": [ { "$ref": "#" } ]
+                    "allOf": [ { "$ref": "#/definitions/subSchema" } ]
                 }
             }
+        },
+        "subSchema": {
+            "oneOf": [
+                {
+                    "allOf": [
+                        { "$ref": "#" },
+                        { "$ref": "http://json-schema.org/draft-05/schema#/definitions/notJsonReference" }
+                    ]
+                },
+                { "$ref": "http://json-schema.org/draft-05/schema#/definitions/notJsonReference#/definitions/jsonReference" }
+            ]
         }
     },
+
     "allOf": [ { "$ref": "http://json-schema.org/draft-05/schema#" } ],
     "properties": {
         "additionalItems": {
             "anyOf": [
                 { "type": "boolean" },
-                { "$ref": "#" }
+                { "$ref": "#/definitions/subSchema" }
             ]
         },
         "additionalProperties": {
             "anyOf": [
                 { "type": "boolean" },
-                { "$ref": "#" }
+                { "$ref": "#/definitions/subSchema" }
             ]
         },
         "dependencies": {
             "additionalProperties": {
                 "anyOf": [
-                    { "$ref": "#" },
+                    { "$ref": "#/definitions/subSchema" },
                     { "type": "array" }
                 ]
             }
         },
         "items": {
             "anyOf": [
-                { "$ref": "#" },
+                { "$ref": "#/definitions/subSchema" },
                 { "$ref": "#/definitions/schemaArray" }
             ]
         },
         "definitions": {
-            "additionalProperties": { "$ref": "#" }
+            "additionalProperties": { "$ref": "#/definitions/subSchema" }
         },
         "patternProperties": {
-            "additionalProperties": { "$ref": "#" }
+            "additionalProperties": { "$ref": "#/definitions/subSchema" }
         },
         "properties": {
-            "additionalProperties": { "$ref": "#" }
+            "additionalProperties": { "$ref": "#/definitions/subSchema" }
         },
         "allOf": { "$ref": "#/definitions/schemaArray" },
         "anyOf": { "$ref": "#/definitions/schemaArray" },
         "oneOf": { "$ref": "#/definitions/schemaArray" },
-        "not": { "$ref": "#" },
+        "not": { "$ref": "#/definitions/subSchema" },
 
         "base": {
             "description": "URI Template resolved as for the 'href' keyword in the Link Description Object.  The resulting URI Reference is resolved against the current URI base and sets the new URI base for URI references within the instance.",

draft-05/schema

@@ -3,10 +3,25 @@
     "id": "http://json-schema.org/draft-05/schema#",
     "title": "Core schema meta-schema",
     "definitions": {
+        "jsonReferece": {
+            "type": "object",
+            "properties": {
+                "$ref": {
+                    "type": "string",
+                    "format": "uriref"
+                }
+            },
+            "required": [ "$ref" ]
+        },
+        "notJsonReference": {
+            "not": {
+                "required": [ "$ref" ]
+            }
+        },
         "schemaArray": {
             "type": "array",
             "minItems": 1,
-            "items": { "$ref": "#" }
+            "items": { "$ref": "#/definitions/subSchema" }
         },
         "positiveInteger": {
             "type": "integer",
@@ -34,6 +49,17 @@
             "items": { "type": "string" },
             "minItems": 1,
             "uniqueItems": true
+        },
+        "subSchema": {
+            "oneOf": [
+                {
+                    "allOf": [
+                        { "$ref": "#" },
+                        { "$ref": "#/definitions/notJsonReference" }
+                    ]
+                },
+                { "$ref": "#/definitions/jsonReference" }
+            ]
         }
     },
     "type": "object",
@@ -81,13 +107,13 @@
         "additionalItems": {
             "anyOf": [
                 { "type": "boolean" },
-                { "$ref": "#" }
+                { "$ref": "#/definitions/subSchema" }
             ],
             "default": {}
         },
         "items": {
             "anyOf": [
-                { "$ref": "#" },
+                { "$ref": "#/definitions/subSchema" },
                 { "$ref": "#/definitions/schemaArray" }
             ],
             "default": {}
@@ -104,30 +130,30 @@
         "additionalProperties": {
             "anyOf": [
                 { "type": "boolean" },
-                { "$ref": "#" }
+                { "$ref": "#/definitions/subSchema" }
             ],
             "default": {}
         },
         "definitions": {
             "type": "object",
-            "additionalProperties": { "$ref": "#" },
+            "additionalProperties": { "$ref": "#/definitions/subSchema" },
             "default": {}
         },
         "properties": {
             "type": "object",
-            "additionalProperties": { "$ref": "#" },
+            "additionalProperties": { "$ref": "#/definitions/subSchema" },
             "default": {}
         },
         "patternProperties": {
             "type": "object",
-            "additionalProperties": { "$ref": "#" },
+            "additionalProperties": { "$ref": "#/definitions/subSchema" },
             "default": {}
         },
         "dependencies": {
             "type": "object",
             "additionalProperties": {
                 "anyOf": [
-                    { "$ref": "#" },
+                    { "$ref": "#/definitions/subSchema" },
                     { "$ref": "#/definitions/stringArray" }
                 ]
             }
@@ -152,7 +178,7 @@
         "allOf": { "$ref": "#/definitions/schemaArray" },
         "anyOf": { "$ref": "#/definitions/schemaArray" },
         "oneOf": { "$ref": "#/definitions/schemaArray" },
-        "not": { "$ref": "#" }
+        "not": { "$ref": "#/definitions/subSchema" }
     },
     "dependencies": {
         "exclusiveMaximum": [ "maximum" ],