raise ParseError for nil in Parser.parse

Author: gfx

lib/graphql/language/parser.rb

@@ -434,6 +434,7 @@ end
 ---- inner ----
 
 def initialize(query_string, filename:, tracer: Tracing::NullTracer)
+  raise GraphQL::ParseError.new("No query string was present", nil, nil, query_string) if query_string.nil?
   @query_string = query_string
   @filename = filename
   @tracer = tracer

lib/graphql/language/parser.y

@@ -129,6 +129,14 @@
     assert_equal schema_string, document.to_query_string
   end
 
+  describe "parse errors" do
+    it "raises parse errors for nil" do
+      assert_raises(GraphQL::ParseError) {
+        GraphQL.parse(nil)
+      }
+    end
+  end
+
   describe ".parse_file" do
     it "assigns filename to all nodes" do
       example_filename = "spec/support/parser/filename_example.graphql"