[Processing] Yet another fix for error message encoding errors (for 2…

….14) (#4042)

* [Processing] Yet another fix for error message encoding errors. Fixes #16102

* [Processing] Follow up 1ede526

python/plugins/processing/core/GeoAlgorithm.py

@@ -213,8 +213,13 @@ def execute(self, progress=None, model=None):
             lines = [self.tr('Uncaught error while executing algorithm')]
             lines.append(traceback.format_exc())
             ProcessingLog.addToLog(ProcessingLog.LOG_ERROR, lines)
+            try:
+                message = unicode(e)
+            except UnicodeDecodeError:
+                # Try with the 'replace' mode (requires e.message instead of e!)
+                message = unicode(e.message, 'utf-8', 'replace')
             raise GeoAlgorithmExecutionException(
-                unicode(e.message, errors='replace') + self.tr(u'\nSee log for more details'))
+                message + self.tr(' \nSee log for more details'), lines, e)
 
     def _checkParameterValuesBeforeExecuting(self):
         for param in self.parameters: