Bugfix: incorrect logic in the parsing of comments fails to detect EOF properly

json_serialization/lexer.nim

@@ -225,19 +225,21 @@ proc skipWhitespace(lexer: var JsonLexer) =
       checkForUnexpectedEof()
       case lexer.stream.peek()
       of '/':
+        advance lexer.stream
         while true:
-          advance lexer.stream
           if not lexer.stream.readable: return
           case lexer.stream.peek()
           of '\r':
             handleCR()
+            break
           of '\n':
             lexer.handleLF()
+            break
           else:
-            discard
+            advance lexer.stream
       of '*':
+        advance lexer.stream
         while true:
-          advance lexer.stream
           if not lexer.stream.readable: return
           case lexer.stream.peek()
           of '\r':
@@ -249,9 +251,9 @@ proc skipWhitespace(lexer: var JsonLexer) =
             checkForUnexpectedEof()
             if lexer.stream.peek() == '/':
               advance lexer.stream
-              return
+              break
           else:
-            discard
+            advance lexer.stream
       else:
         error errCommentExpected
     of ' ', '\t':

tests/test_serialization.nim

@@ -261,3 +261,13 @@ suite "toJson tests":
   test "Holders of JsonNode":
     testJsonHolders HasJsonNode
 
+  test "Json with comments":
+    const jsonContent = staticRead "./cases/comments.json"
+
+    try:
+      let decoded = Json.decode(jsonContent, JsonNode)
+      check decoded["tasks"][0]["label"] == newJString("nim-beacon-chain build")
+    except SerializationError as err:
+      checkpoint err.formatMsg("./cases/comments.json")
+      fail
+