fallback: preserve list_hook results with use_list=False

msgpack/fallback.py

@@ -521,10 +521,11 @@ def _unpack(self, execute=EX_CONSTRUCT):
             ret = newlist_hint(n)
             for i in range(n):
                 ret.append(self._unpack(EX_CONSTRUCT))
+            if not self._use_list:
+                ret = tuple(ret)
             if self._list_hook is not None:
                 ret = self._list_hook(ret)
-            # TODO is the interaction between `list_hook` and `use_list` ok?
-            return ret if self._use_list else tuple(ret)
+            return ret
         if typ == TYPE_MAP:
             if execute == EX_SKIP:
                 for i in range(n):

test/test_obj.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python
 
+from io import BytesIO
+
 from pytest import raises
 
-from msgpack import packb, unpackb
+from msgpack import Unpacker, packb, unpackb
 
 
 def _decode_complex(obj):
@@ -74,6 +76,29 @@ def test_array_hook():
     assert unpacked == "123"
 
 
+def test_array_hook_with_use_list_false():
+    seen = []
+
+    def hook(items):
+        seen.append(items)
+        return {"items": items}
+
+    packed = packb([1, 2])
+    expected = {"items": (1, 2)}
+    assert unpackb(packed, use_list=False, list_hook=hook) == expected
+
+    stream = packed + packb(3)
+    unpackers = [
+        Unpacker(use_list=False, list_hook=hook),
+        Unpacker(BytesIO(stream), use_list=False, list_hook=hook),
+    ]
+    unpackers[0].feed(stream)
+    for unpacker in unpackers:
+        assert unpacker.unpack() == expected
+        assert unpacker.unpack() == 3
+    assert seen == [(1, 2)] * 3
+
+
 class DecodeError(Exception):
     pass