Merge pull request #659 from dmitry-ra/fix-issue-638

Fix #638: Parser hangs on stream of `%Y`
aaubry · Jul 13, 2022 · 6e8d6d1 · 6e8d6d1
2 parents 28c32c5 + 898dea8
commit 6e8d6d1
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Showing 2 changed files with 25 additions and 1 deletion.
diff --git a/YamlDotNet.Test/Serialization/SerializationTests.cs b/YamlDotNet.Test/Serialization/SerializationTests.cs
@@ -216,6 +216,23 @@ public void SerializeCircularReference()
             action.ShouldNotThrow();
         }
 
+        [Fact]
+        public void DeserializeIncompleteDirective()
+        {
+            Action action = () => Deserializer.Deserialize<object>(UsingReaderFor("%Y"));
+
+            action.ShouldThrow<SyntaxErrorException>()
+                .WithMessage("While scanning a directive, found unexpected end of stream.");
+        }
+
+        [Fact]
+        public void DeserializeSkippedReservedDirective()
+        {
+            Action action = () => Deserializer.Deserialize<object>(UsingReaderFor("%Y "));
+
+            action.ShouldNotThrow();
+        }
+
         [Fact]
         public void DeserializeCustomTags()
         {

diff --git a/YamlDotNet/Core/Scanner.cs b/YamlDotNet/Core/Scanner.cs
@@ -796,7 +796,7 @@ private void FetchDirective()
 
                 default:
                     // warning: skipping reserved directive line
-                    while (!analyzer.Check('#') && !analyzer.IsBreak())
+                    while (!analyzer.EndOfInput && !analyzer.Check('#') && !analyzer.IsBreak())
                     {
                         Skip();
                     }
@@ -2284,6 +2284,13 @@ private string ScanDirectiveName(in Mark start)
                 throw new SyntaxErrorException(start, cursor.Mark(), "While scanning a directive, could not find expected directive name.");
             }
 
+            // Check for end of stream
+
+            if (analyzer.EndOfInput)
+            {
+                throw new SyntaxErrorException(start, cursor.Mark(), "While scanning a directive, found unexpected end of stream.");
+            }
+
             // Check for an blank character after the name.
 
             if (!analyzer.IsWhiteBreakOrZero())