The RESP3 null case can skip the initial TryReadUnsignedLengthHeader detection, so we better check after the call. If we do that check, we might as well delete the previous check.

Author: prvyk

libs/common/RespReadUtils.cs

@@ -316,17 +316,14 @@ public static bool TryReadUnsignedLengthHeader(out int length, ref byte* ptr, by
             if (ptr + 3 > end)
                 return false;
 
-            var readHead = ptr + 1;
-            var negative = *readHead == '-';
+            if (!TryReadSignedLengthHeader(out length, ref ptr, end, expectedSigil))
+                return false;
 
-            if (negative)
+            if (length < 0)
             {
                 RespParsingException.ThrowInvalidStringLength(length);
             }
 
-            if (!TryReadSignedLengthHeader(out length, ref ptr, end, expectedSigil))
-                return false;
-
             return true;
         }
 
@@ -924,7 +921,7 @@ public static bool TryReadStringResponseWithLengthHeader(out string result, ref
         /// <exception cref="RespParsingException">Thrown if unexpected token is read.</exception>
         /// <exception cref="RespParsingException">Thrown if integer overflow occurs.</exception>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static bool TryReadPtrWithSignedLengthHeader(ref byte* stringPtr, ref int length, ref byte* ptr, byte* end)
+        static bool TryReadPtrWithSignedLengthHeader(ref byte* stringPtr, ref int length, ref byte* ptr, byte* end)
         {
             // Parse RESP string header
             if (!TryReadSignedLengthHeader(out length, ref ptr, end))