update m_characterSet and m_setNamesPayload initialization

Author: okramarenko

src/SingleStoreConnector/Core/ServerSession.cs

@@ -485,10 +485,9 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 				SupportsQueryAttributes = (ServerCapabilities & ProtocolCapabilities.QueryAttributes) != 0;
 				m_supportsSessionTrack = (ServerCapabilities & ProtocolCapabilities.SessionTrack) != 0;
 				var serverSupportsSsl = (ServerCapabilities & ProtocolCapabilities.Ssl) != 0;
-				m_characterSet = S2ServerVersion.Version >= S2Versions.SupportsUtf8Mb4 ? CharacterSet.Utf8Mb4GeneralCaseInsensitive : CharacterSet.Utf8GeneralCaseInsensitive;
-				m_setNamesPayload = S2ServerVersion.Version >= S2Versions.SupportsUtf8Mb4 ?
-					(SupportsQueryAttributes ? s_setNamesUtf8mb4WithAttributesPayload : s_setNamesUtf8mb4NoAttributesPayload) :
-					(SupportsQueryAttributes ? s_setNamesUtf8WithAttributesPayload : s_setNamesUtf8NoAttributesPayload);
+				// Default to plain UTF‑8 until we’ve probed the server’s real version
+				m_characterSet = CharacterSet.Utf8GeneralCaseInsensitive;
+				m_setNamesPayload = SupportsQueryAttributes ? s_setNamesUtf8WithAttributesPayload : s_setNamesUtf8NoAttributesPayload;
 
 				// disable pipelining for SingleStore
 				m_supportsPipelining = false;
@@ -549,10 +548,25 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 			if (m_useCompression)
 				m_payloadHandler = new CompressedPayloadHandler(m_payloadHandler.ByteHandler);
 
-			// set 'collation_connection' to the server default
-			await SendAsync(m_setNamesPayload, ioBehavior, cancellationToken).ConfigureAwait(false);
-			payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
-			OkPayload.Verify(payload.Span, SupportsDeprecateEof, SupportsSessionTrack);
+			// set 'collation_connection' to the server default (probing utf8mb4 support)
+			try
+			{
+				var utf8Mb4Payload = SupportsQueryAttributes
+					? s_setNamesUtf8mb4WithAttributesPayload
+					: s_setNamesUtf8mb4NoAttributesPayload;
+				await SendAsync(utf8Mb4Payload, ioBehavior, cancellationToken).ConfigureAwait(false);
+				payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
+				OkPayload.Verify(payload.Span, SupportsDeprecateEof, SupportsSessionTrack);
+
+				m_characterSet = CharacterSet.Utf8Mb4GeneralCaseInsensitive;
+				m_setNamesPayload = utf8Mb4Payload;
+			}
+			catch (SingleStoreException)
+			{
+				await SendAsync(m_setNamesPayload, ioBehavior, cancellationToken).ConfigureAwait(false);
+				var reply = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
+				OkPayload.Verify(reply.Span, SupportsDeprecateEof, SupportsSessionTrack);
+			}
 
 			await GetRealServerDetailsAsync(ioBehavior, CancellationToken.None).ConfigureAwait(false);