feat: create opt-out setting "ForceUnicode", for sessions which shall not force Unicode communication

https://www.heidisql.com/forum.php?t=45113

Author: ansgarbecker

source/apphelpers.pas

@@ -188,7 +188,7 @@   TWinControlHelper = class helper for TWinControl
     asWrapLongLines, asCodeFolding, asDisplayBLOBsAsText, asSingleQueries, asMemoEditorWidth, asMemoEditorHeight, asMemoEditorMaximized,
     asMemoEditorWrap, asMemoEditorHighlighter, asMemoEditorAlwaysFormatCode, asDelimiter, asSQLHelpWindowLeft, asSQLHelpWindowTop, asSQLHelpWindowWidth,
     asSQLHelpWindowHeight, asSQLHelpPnlLeftWidth, asSQLHelpPnlRightTopHeight, asHost,
-    asUser, asPassword, asCleartextPluginEnabled, asWindowsAuth, asLoginPrompt, asPort, asLibrary, asAllProviders,
+    asUser, asPassword, asCleartextPluginEnabled, asForceUnicode, asWindowsAuth, asLoginPrompt, asPort, asLibrary, asAllProviders,
     asSSHtunnelActive, asPlinkExecutable, asSshExecutable, asSSHtunnelHost, asSSHtunnelHostPort, asSSHtunnelPort, asSSHtunnelUser,
     asSSHtunnelPassword, asSSHtunnelTimeout, asSSHtunnelPrivateKey, asSSLActive, asSSLKey,
     asSSLCert, asSSLCA, asSSLCipher, asSSLVerification, asSSLWarnUnused, asNetType, asCompressed, asLocalTimeZone, asQueryTimeout, asKeepAlive,
@@ -3911,6 +3911,7 @@ constructor TAppSettings.Create;
   InitSetting(asUser,                             'User',                                  0, False, '', True);
   InitSetting(asPassword,                         'Password',                              0, False, '', True);
   InitSetting(asCleartextPluginEnabled,           'CleartextPluginEnabled',                0, False, '', True);
+  InitSetting(asForceUnicode,                     'ForceUnicode',                          0, True, '', True);
   InitSetting(asWindowsAuth,                      'WindowsAuth',                           0, False, '', True);
   InitSetting(asLoginPrompt,                      'LoginPrompt',                           0, False, '', True);
   InitSetting(asPort,                             'Port',                                  0, False, '', True);

source/dbconnection.pas

@@ -310,7 +310,7 @@   TConnectionParameters = class(TObject)
       FIgnoreDatabasePattern: String;
       FPort, FSSHPort, FSSHLocalPort, FSSHTimeout, FCounter, FQueryTimeout, FKeepAlive, FSSLVerification: Integer;
       FSSHActive, FLoginPrompt, FCompressed, FLocalTimeZone, FFullTableStatus,
-      FWindowsAuth, FWantSSL, FIsFolder, FCleartextPluginEnabled: Boolean;
+      FWindowsAuth, FWantSSL, FIsFolder, FCleartextPluginEnabled, FForceUnicode: Boolean;
       FSessionColor: TColor;
       FLastConnect: TDateTime;
       FLogFileDdl: Boolean;
@@ -375,6 +375,7 @@   TConnectionParameters = class(TObject)
       property LoginPrompt: Boolean read FLoginPrompt write FLoginPrompt;
       property WindowsAuth: Boolean read FWindowsAuth write FWindowsAuth;
       property CleartextPluginEnabled: Boolean read FCleartextPluginEnabled write FCleartextPluginEnabled;
+      property ForceUnicode: Boolean read FForceUnicode write FForceUnicode;
       property AllDatabasesStr: String read FAllDatabases write FAllDatabases;
       property AllDatabasesList: TStringList read GetAllDatabasesList;
       property LibraryOrProvider: String read FLibraryOrProvider write FLibraryOrProvider;
@@ -1405,6 +1406,7 @@ constructor TConnectionParameters.Create;
   FLoginPrompt := AppSettings.GetDefaultBool(asLoginPrompt);
   FWindowsAuth := AppSettings.GetDefaultBool(asWindowsAuth);
   FCleartextPluginEnabled := AppSettings.GetDefaultBool(asCleartextPluginEnabled);
+  FForceUnicode := AppSettings.GetDefaultBool(asForceUnicode);
   FUsername := DefaultUsername;
   FPassword := AppSettings.GetDefaultString(asPassword);
   FPort := DefaultPort;
@@ -1479,6 +1481,7 @@ constructor TConnectionParameters.Create(SessionRegPath: String);
     FLoginPrompt := AppSettings.ReadBool(asLoginPrompt);
     FWindowsAuth := AppSettings.ReadBool(asWindowsAuth);
     FCleartextPluginEnabled := AppSettings.ReadBool(asCleartextPluginEnabled);
+    FForceUnicode := AppSettings.ReadBool(asForceUnicode);
     FPort := MakeInt(AppSettings.ReadString(asPort));
     FCompressed := AppSettings.ReadBool(asCompressed);
     FAllDatabases := AppSettings.ReadString(asDatabases);
@@ -1555,6 +1558,7 @@ procedure TConnectionParameters.SaveToRegistry;
     AppSettings.WriteString(asHost, FHostname);
     AppSettings.WriteBool(asWindowsAuth, FWindowsAuth);
     AppSettings.WriteBool(asCleartextPluginEnabled, FCleartextPluginEnabled);
+    AppSettings.WriteBool(asForceUnicode, FForceUnicode);
     AppSettings.WriteString(asUser, FUsername);
     AppSettings.WriteString(asPassword, encrypt(FPassword));
     AppSettings.WriteBool(asLoginPrompt, FLoginPrompt);
@@ -4611,10 +4615,14 @@ procedure TMySQLConnection.SetCharacterSet(CharsetName: String);
   FStatementNum := 0;
   Log(lcInfo, 'Changing character set from '+CharacterSet+' to '+CharsetName);
   Return := FLib.mysql_set_character_set(FHandle, PAnsiChar(Utf8Encode(CharsetName)));
+  // Return value never seems to be <> 0, not even on v3.23 servers, we check it anyway:
   if Return <> 0 then
-    raise EDbError.Create(LastErrorMsg)
-  else
-    FIsUnicode := CharsetName.StartsWith('utf', True);
+    raise EDbError.Create(LastErrorMsg);
+  // Check opt-out setting: if disabled, align the internal IsUnicode flag to the connection charset
+  if not FParameters.ForceUnicode then begin
+    FIsUnicode := CharacterSet.StartsWith('utf', True);
+    Log(lcInfo, 'ForceUnicode disabled in settings. Internal IsUnicode flag is now: ' + FIsUnicode.ToInteger.ToString)
+  end;
 end;