Use default base URI for exclusive refs

In drafts 7 and earlier, all keywords except `definitions` are ignored
when `$ref` is present. This includes `$id`, which means refs are
resolved using the schema's inherited base URI (default or parent).
Currently, when `$id` is present, the inherited base URI isn't being
registered as a ref resolution resource (with `ID_KEYWORD_CLASS.new`),
which causes JSON pointer ref resolution to fail. The fix here is to add
the exclusive ref case for the `ID_KEYWORD_CLASS.new` call.

The rest of the changes are from if/else cleanup.

Closes: #146

Author: davishmcclurg

lib/json_schemer/schema.rb

@@ -329,28 +329,27 @@ def parse
         VOCABULARY_KEYWORD_CLASS.new(vocabulary, self, '$vocabulary')
       end
 
-      if root == self && (!value.is_a?(Hash) || !value.key?(meta_schema.id_keyword))
+      keywords = meta_schema.keywords
+      exclusive_ref = value.is_a?(Hash) && value.key?('$ref') && keywords.fetch('$ref').exclusive?
+
+      if root == self && (!value.is_a?(Hash) || !value.key?(meta_schema.id_keyword) || exclusive_ref)
         ID_KEYWORD_CLASS.new(base_uri, self, meta_schema.id_keyword)
       end
 
-      if value.is_a?(Hash)
-        keywords = meta_schema.keywords
-
-        if value.key?('$ref') && keywords.fetch('$ref').exclusive?
-          @parsed['$ref'] = keywords.fetch('$ref').new(value.fetch('$ref'), self, '$ref')
-          defs_keyword = meta_schema.defs_keyword
-          if value.key?(defs_keyword) && keywords.key?(defs_keyword)
-            @parsed[defs_keyword] = keywords.fetch(defs_keyword).new(value.fetch(defs_keyword), self, defs_keyword)
-          end
-        else
-          keyword_order = meta_schema.keyword_order
-          last = keywords.size
-
-          value.sort do |(keyword_a, _value_a), (keyword_b, _value_b)|
-            keyword_order.fetch(keyword_a, last) <=> keyword_order.fetch(keyword_b, last)
-          end.each do |keyword, value|
-            @parsed[keyword] ||= keywords.fetch(keyword, UNKNOWN_KEYWORD_CLASS).new(value, self, keyword)
-          end
+      if exclusive_ref
+        @parsed['$ref'] = keywords.fetch('$ref').new(value.fetch('$ref'), self, '$ref')
+        defs_keyword = meta_schema.defs_keyword
+        if value.key?(defs_keyword) && keywords.key?(defs_keyword)
+          @parsed[defs_keyword] = keywords.fetch(defs_keyword).new(value.fetch(defs_keyword), self, defs_keyword)
+        end
+      elsif value.is_a?(Hash)
+        keyword_order = meta_schema.keyword_order
+        last = keywords.size
+
+        value.sort do |(keyword_a, _value_a), (keyword_b, _value_b)|
+          keyword_order.fetch(keyword_a, last) <=> keyword_order.fetch(keyword_b, last)
+        end.each do |keyword, value|
+          @parsed[keyword] ||= keywords.fetch(keyword, UNKNOWN_KEYWORD_CLASS).new(value, self, keyword)
         end
       end
 

test/ref_test.rb

@@ -379,4 +379,20 @@ def test_exclusive_ref_supports_definitions
     assert(schema.valid?(1))
     refute(schema.valid?('1'))
   end
+
+  def test_exclusive_ref_supports_definitions_with_id_and_json_pointer
+    schema = JSONSchemer.schema({
+      '$schema' => 'http://json-schema.org/draft-07/schema#',
+      '$id' => 'https://example.com/schema',
+      '$ref' => '#/definitions/yah',
+      'definitions' => {
+        'yah' => {
+          '$id' => '#yah',
+          'type' => 'integer'
+        }
+      }
+    })
+    assert(schema.valid?(1))
+    refute(schema.valid?('1'))
+  end
 end