From a4f755b4f5ae8cea8e79a1db2a13b5673189f6c4 Mon Sep 17 00:00:00 2001
From: hanjinliu <hanjin.liu@bs.s.u-tokyo.ac.jp>
Date: Mon, 9 May 2022 23:10:56 +0900
Subject: [PATCH] fix ListEdit annotation check

---
 magicgui/widgets/_concrete.py |  3 ++-
 tests/test_widgets.py         | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/magicgui/widgets/_concrete.py b/magicgui/widgets/_concrete.py
index 78a469d29..f787e5396 100644
--- a/magicgui/widgets/_concrete.py
+++ b/magicgui/widgets/_concrete.py
@@ -654,8 +654,9 @@ def __init__(
         self.margins = (0, 0, 0, 0)
 
         if not isinstance(value, _Unset):
+            # check type consistency
             types = {type(a) for a in value}
-            if len(types) == 1:
+            if len(types) <= 1:
                 if self._args_type is None:
                     self._args_type = types.pop()
             else:
diff --git a/tests/test_widgets.py b/tests/test_widgets.py
index 1bb80e800..81f7a80e7 100644
--- a/tests/test_widgets.py
+++ b/tests/test_widgets.py
@@ -862,6 +862,18 @@ def f3(x: List[int] = [0]):
     assert f3.x[0].max == 10
     assert f3.x[0].step == 5
 
+    @magicgui
+    def f4(x: List[int] = ()):  # type: ignore
+        pass
+
+    assert type(f4.x) is widgets.ListEdit
+    assert f4.x.annotation == List[int]
+    assert f4.x._args_type is int
+    assert f4.x.value == []
+    f4.x.btn_plus.changed()
+    assert type(f4.x[0]) is widgets.SpinBox
+    assert f4.x.value == [0]
+
 
 def test_tuple_edit():
     """Test TupleEdit."""