From 3b0c9eafa4eb75c6257ec5cd08cf6d25c31119a6 Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Fri, 9 Oct 2020 19:32:25 +0300
Subject: [PATCH] Bugfix: incorrect logic in the parsing of comments fails to
 detect EOF properly

---
 json_serialization/lexer.nim | 12 +++++++-----
 tests/test_serialization.nim | 10 ++++++++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/json_serialization/lexer.nim b/json_serialization/lexer.nim
index 50d4a5e..15cbfdb 100644
--- a/json_serialization/lexer.nim
+++ b/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':
diff --git a/tests/test_serialization.nim b/tests/test_serialization.nim
index 3dbd100..e267782 100644
--- a/tests/test_serialization.nim
+++ b/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
+