Handle exclusive bounds on Param widgets (#8165)

* Handle exclusive bounds on Param widgets

* Small refactor

Author: philippjfr

panel/param.py

@@ -488,17 +488,24 @@ def widget(self_or_cls, p_name: str, parameterized: param.Parameterized | None =
             kw['options'] = options
         if hasattr(p_obj, 'get_soft_bounds'):
             bounds = p_obj.get_soft_bounds()
-            if bounds[0] is not None:
-                kw['start'] = bounds[0]
-            if bounds[1] is not None:
-                kw['end'] = bounds[1]
+            is_int = isinstance(p_obj, param.Integer)
+            start, end = bounds
+            istart, iend = getattr(p_obj, 'inclusive_bounds', (True, True))
+            if is_int and not istart:
+                start += 1
+            if start is not None:
+                kw['start'] = start
+            if is_int and not iend:
+                end -= 1
+            if end is not None:
+                kw['end'] = end
             if (('start' not in kw or 'end' not in kw) and
                 not isinstance(p_obj, (param.Date, param.CalendarDate))):
                 # Do not change widget class if mapping was overridden
                 if not widget_class_overridden:
                     if isinstance(p_obj, param.Number):
                         widget_class = self_or_cls.input_widgets[float]
-                        if isinstance(p_obj, param.Integer):
+                        if is_int:
                             widget_class = self_or_cls.input_widgets[int]
                     elif not issubclass(widget_class, LiteralInput):
                         widget_class = self_or_cls.input_widgets['literal']
@@ -543,11 +550,27 @@ def link_widget(change):
             p_key = p_name if config.nthreads is None else (threading.get_ident(), p_name)
             if p_key in updating:
                 return
+            new = change.new
+            reset = False
+            if isinstance(p_obj, param.Number) and not isinstance(p_obj, param.Integer):
+                istart, iend = getattr(p_obj, 'inclusive_bounds', (True, True))
+                bounds = p_obj.get_soft_bounds()
+                if (not istart and new == bounds[0]) or (not iend and new == bounds[1]):
+                    new = change.old
+                    reset = True
+            elif isinstance(p_obj, param.Range):
+                istart, iend = getattr(p_obj, 'inclusive_bounds', (True, True))
+                bounds = p_obj.get_soft_bounds()
+                if (not istart and new[0] == bounds[0]) or (not iend and new[1] == bounds[1]):
+                    new = change.old
+                    reset = True
             try:
                 updating.append(p_key)
-                parameterized.param.update(**{p_name: change.new})
+                parameterized.param.update(**{p_name: new})
             finally:
                 updating.remove(p_key)
+                if reset:
+                    widget.value = new
 
         if hasattr(param, 'Event') and isinstance(p_obj, param.Event):
             def event(change):

panel/tests/test_param.py

@@ -431,6 +431,69 @@ class Test(param.Parameterized):
     assert select.disabled == False
 
 
+def test_integer_param_exclusive_bounds(document, comm):
+    class Test(param.Parameterized):
+        a = param.Integer(default=1, bounds=(0, 10), inclusive_bounds=(False, False))
+
+    test = Test()
+    test_pane = Param(test)
+    model = test_pane.get_root(document, comm=comm)
+
+    widget = model.children[1]
+    assert isinstance(widget, Slider)
+    assert widget.start == 1
+    assert widget.end == 9
+    assert widget.value == 1
+    assert widget.disabled == False
+
+def test_number_param_exclusive_bounds(document, comm):
+    class Test(param.Parameterized):
+        a = param.Number(default=1, bounds=(0, 10), inclusive_bounds=(False, False))
+
+    test = Test()
+    test_pane = Param(test)
+    model = test_pane.get_root(document, comm=comm)
+
+    widget = model.children[1]
+    assert isinstance(widget, Slider)
+    assert widget.start == 0
+    assert widget.end == 10
+    assert widget.value == 1
+    assert widget.disabled == False
+
+    widget.value = 0.1
+    assert test.a == 0.1
+
+    widget.value = 0
+    assert widget.value == 0.1
+
+    widget.value = 10
+    assert widget.value == 0.1
+
+def test_range_param_exclusive_bounds(document, comm):
+    class Test(param.Parameterized):
+        a = param.Range(default=(1, 9), bounds=(0, 10), inclusive_bounds=(False, False))
+
+    test = Test()
+    test_pane = Param(test)
+    model = test_pane.get_root(document, comm=comm)
+
+    widget = model.children[1]
+    assert isinstance(widget, BkRangeSlider)
+    assert widget.start == 0
+    assert widget.end == 10
+    assert widget.value == (1, 9)
+    assert widget.disabled == False
+
+    widget.value = (0.1, 9.9)
+    assert test.a == (0.1, 9.9)
+
+    widget.value = (0, 9.9)
+    assert widget.value == (0.1, 9.9)
+
+    widget.value = (0.1, 10)
+    assert widget.value == (0.1, 9.9)
+
 def test_number_input_none_support():
     class Test(param.Parameterized) :
         number = param.Number(default=0, allow_None=True)