make sure types are declared in spec linter

docs/source/_static/rest-api.yml

@@ -1465,6 +1465,7 @@ paths:
         content:
           application/x-www-form-urlencoded:
             schema:
+              type: object
               required:
                 - client_id
                 - client_secret
@@ -1481,6 +1482,8 @@ paths:
                 grant_type:
                   type: string
                   description: The grant type (always 'authorization_code')
+                  enum:
+                    - authorization_code
                 code:
                   type: string
                   description: The code provided by the authorization redirect

redocly.yaml

@@ -7,3 +7,44 @@ apis:
     rules:
       info-license-url: off
       operation-4xx-response: off
+
+# custom rules
+# https://redocly.com/docs/cli/rules/configurable-rules/
+rules:
+  rule/required-items-in-array-schemas:
+    subject:
+      type: Schema
+    assertions:
+      required:
+        - items
+    where:
+      - subject:
+          type: Schema
+          property: type
+        assertions:
+          const: array
+          defined: true
+    message: The 'items' field is required for schemas of array type.
+
+  rule/require-schema-type:
+    subject:
+      type: Schema
+      property: type
+    assertions:
+      defined: true
+    message: schema missing type
+    where:
+      # don't require type on schemas that reference other schemas, which already must specify type
+      - subject:
+          type: Schema
+          property: allOf
+        assertions:
+          defined: false
+
+  rule/require-parameter-schema:
+    subject:
+      type: Parameter
+      property: schema
+    assertions:
+      defined: true
+    message: Parameter missing schema