Fix special ansi sequences not ignored and producing wrong colors

colorama/ansitowin32.py

@@ -222,13 +222,27 @@ def extract_params(self, command, paramstring):
 
     def call_win32(self, command, params):
         if command == 'm':
+            # Ansi sequences started by specific param may need to be ignored, see #217
+            skip, skip_count = False, None
             for param in params:
+                if skip:
+                    if skip_count is not None:
+                        skip_count -= 1
+                        continue
+                    if param in (2, 5):
+                        skip_count = 1 if param == 5 else 3
+                        continue
+                    skip = False
+                    skip_count = False
                 if param in self.win32_calls:
                     func_args = self.win32_calls[param]
                     func = func_args[0]
                     args = func_args[1:]
                     kwargs = dict(on_stderr=self.on_stderr)
                     func(*args, **kwargs)
+                elif param in (38, 48):
+                    skip = True
+
         elif command in 'J':
             winterm.erase_screen(params[0], on_stderr=self.on_stderr)
         elif command in 'K':

colorama/tests/ansitowin32_test.py

@@ -227,6 +227,30 @@ def test_osc_codes(self):
             for code in data:
                 stream.write(code)
             self.assertEqual(winterm.set_title.call_count, 2)
+
+    def testInvalidSequencesAreSkipped(self):
+        sequences = [
+            (38, 5, 46),
+            (38, 2, 120, 33, 255),
+            (48, 5, 31),
+            (48, 2, 166, 226, 46),
+            (38, 48, 5, 46),
+        ]
+        for sequence in sequences:
+            listener = Mock()
+            stream = AnsiToWin32(listener)
+            stream.win32_calls = {
+                2: (lambda *_, **__: listener(2),),
+                5: (lambda *_, **__: listener(5),),
+                33: (lambda *_, **__: listener(33),),
+                46: (lambda *_, **__: listener(46),),
+                166: (lambda *_, **__: listener(166),),
+                226: (lambda *_, **__: listener(226),),
+                255: (lambda *_, **__: listener(255),),
+            }
+            stream.call_win32('m', sequence)
+            self.assertFalse(listener.called)
+
 
 if __name__ == '__main__':
     main()