Fix FunctionGui behavior as a class method

magicgui/widgets/_function_gui.py

@@ -184,6 +184,7 @@ def __init__(
         self._param_options = param_options
         self._result_name = ""
         self._call_count: int = 0
+        self._bound_instances: dict[int, FunctionGui] = {}
 
         # a deque of Progressbars to be created by (possibly nested) tqdm_mgui iterators
         self._tqdm_pbars: Deque[ProgressBar] = deque()
@@ -373,8 +374,6 @@ def copy(self) -> FunctionGui:
             app=None,
         )
 
-    _bound_instances: dict[int, FunctionGui] = {}
-
     def __get__(self, obj, objtype=None) -> FunctionGui:
         """Provide descriptor protocol.
 

tests/test_magicgui.py

@@ -508,6 +508,26 @@ def method(self, sigma: float = 1):
     assert b.method() == ("b", 5)
 
 
+def test_function_binding_multiple():
+    class MyObject:
+        def __init__(self):
+            pass
+
+        @magicgui
+        def method_0(self, sigma: float = 1):
+            pass
+
+        @magicgui
+        def method_1(self, sigma: float = 2):
+            pass
+
+    a = MyObject()
+    assert MyObject.method_0 is not a.method_0
+    assert a.method_0 is not a.method_1
+    assert a.method_0.sigma.value == 1
+    assert a.method_1.sigma.value == 2
+
+
 def test_call_count():
     """Test that a function gui remembers how many times it's been called."""