Fixes previous_key_sequences: make a copy of key_sequences before calling the handler + initialize to an empty list.

2 files changed, 44 insertions, 2 deletions

diff --git a/prompt_toolkit/key_binding/input_processor.py b/prompt_toolkit/key_binding/input_processor.py
index a57e3aa3..51a31108 100644
--- a/prompt_toolkit/key_binding/input_processor.py
+++ b/prompt_toolkit/key_binding/input_processor.py
@@ -93,7 +93,7 @@ class InputProcessor(object):
         self.reset()
 
     def reset(self):
-        self._previous_key_sequence = None
+        self._previous_key_sequence = []
         self._previous_handler = None
 
         self._process_coroutine = self._process()
@@ -173,7 +173,7 @@ class InputProcessor(object):
 
                 # Exact matches found, call handler.
                 if not is_prefix_of_longer_match and matches:
-                    self._call_handler(matches[-1], key_sequence=buffer)
+                    self._call_handler(matches[-1], key_sequence=buffer[:])
                     del buffer[:]  # Keep reference.
 
                 # No match found.
diff --git a/tests/test_key_binding.py b/tests/test_key_binding.py
index 04f6b5f8..d706c444 100644
--- a/tests/test_key_binding.py
+++ b/tests/test_key_binding.py
@@ -96,3 +96,45 @@ def test_common_prefix(processor, handlers):
     processor.process_keys()
 
     assert handlers.called == ['control_x', 'control_d']
+
+
+def test_previous_key_sequence(processor, handlers):
+    """
+    test whether we receive the correct previous_key_sequence.
+    """
+    events = []
+    def handler(event):
+        events.append(event)
+
+    # Build registry.
+    registry = Registry()
+    registry.add_binding('a', 'a')(handler)
+    registry.add_binding('b', 'b')(handler)
+    processor = InputProcessor(registry, lambda: None)
+
+    # Create processor and feed keys.
+    processor.feed(KeyPress('a', 'a'))
+    processor.feed(KeyPress('a', 'a'))
+    processor.feed(KeyPress('b', 'b'))
+    processor.feed(KeyPress('b', 'b'))
+    processor.process_keys()
+
+    # Test.
+    assert len(events) == 2
+    assert len(events[0].key_sequence) == 2
+    assert events[0].key_sequence[0].key == 'a'
+    assert events[0].key_sequence[0].data == 'a'
+    assert events[0].key_sequence[1].key == 'a'
+    assert events[0].key_sequence[1].data == 'a'
+    assert events[0].previous_key_sequence == []
+
+    assert len(events[1].key_sequence) == 2
+    assert events[1].key_sequence[0].key == 'b'
+    assert events[1].key_sequence[0].data == 'b'
+    assert events[1].key_sequence[1].key == 'b'
+    assert events[1].key_sequence[1].data == 'b'
+    assert len(events[1].previous_key_sequence) == 2
+    assert events[1].previous_key_sequence[0].key == 'a'
+    assert events[1].previous_key_sequence[0].data == 'a'
+    assert events[1].previous_key_sequence[1].key == 'a'
+    assert events[1].previous_key_sequence[1].data == 'a'