Don't make replacements in block strings

Author: rmosolgo

lib/graphql/language/lexer.rb

@@ -114,23 +114,20 @@ def string_value
         is_block = str.start_with?('"""')
         if is_block
           str.gsub!(/\A"""|"""\z/, '')
+          return Language::BlockString.trim_whitespace(str)
         else
           str.gsub!(/\A"|"\z/, '')
-        end
 
-        if is_block
-          str = Language::BlockString.trim_whitespace(str)
-        end
-
-        if !str.valid_encoding? || !str.match?(VALID_STRING)
-          raise_parse_error("Bad unicode escape in #{str.inspect}")
-        else
-          Lexer.replace_escaped_characters_in_place(str)
-
-          if !str.valid_encoding?
+          if !str.valid_encoding? || !str.match?(VALID_STRING)
             raise_parse_error("Bad unicode escape in #{str.inspect}")
           else
-            str
+            Lexer.replace_escaped_characters_in_place(str)
+
+            if !str.valid_encoding?
+              raise_parse_error("Bad unicode escape in #{str.inspect}")
+            else
+              str
+            end
           end
         end
       end

spec/fixtures/unicode_escapes/query1.graphql

@@ -0,0 +1,6 @@
+{
+  example1: getString(string: "\u0064") # should return "d"
+  example2: getString(string: "\\u0064") # should return "\\u0064"
+  # example3: getString(string: "\u006") # validation error
+  example4: getString(string: "\\u006") # should return "\\u006"
+}

spec/fixtures/unicode_escapes/query2.graphql

@@ -0,0 +1,6 @@
+query bug2 {
+  example1: getString(string: """\a""") # should be "\\a"
+  example2: getString(string: """\u006""") # should be "\\u006"
+  example3: getString(string: """\n""") # should be "\\n"
+  example4: getString(string: """\u0064""") # should be "\\u0064"
+}

spec/graphql/types/string_spec.rb

@@ -129,5 +129,15 @@ def get_string(string:)
       res2 = UnicodeEscapeSchema.execute(error_query_str)
       assert_equal ["Expected string or block string, but it was malformed"], res2["errors"].map { |err| err["message"] }
     end
+
+    it "parses escapes properly in triple-quoted strings" do
+      query_str = File.read("./spec/fixtures/unicode_escapes/query2.graphql")
+      res = UnicodeEscapeSchema.execute(query_str)
+      # No replacing in block strings:
+      assert_equal "\\a", res["data"]["example1"]
+      assert_equal "\\u006", res["data"]["example2"]
+      assert_equal "\\n", res["data"]["example3"]
+      assert_equal "\\u0064", res["data"]["example4"]
+    end
   end
 end