Fix partial autorange when range contains None elements

plotly/basedatatypes.py

@@ -1447,10 +1447,12 @@ def _select_layout_subplots_by_prefix(
 
         layout_keys_filters = [
             lambda k: k.startswith(prefix) and self.layout[k] is not None,
-            lambda k: row is None
-            or container_to_row_col.get(k, (None, None, None))[0] == row,
-            lambda k: col is None
-            or container_to_row_col.get(k, (None, None, None))[1] == col,
+            lambda k: (
+                row is None or container_to_row_col.get(k, (None, None, None))[0] == row
+            ),
+            lambda k: (
+                col is None or container_to_row_col.get(k, (None, None, None))[1] == col
+            ),
             lambda k: (
                 secondary_y is None
                 or container_to_row_col.get(k, (None, None, None))[2] == secondary_y
@@ -3991,6 +3993,32 @@ def _perform_update(plotly_obj, update_obj, overwrite=False):
                     # Assign non-compound value
                     plotly_obj[key] = val
 
+            # Handle partial autorange for axis range with None elements
+            # -----------------------------------------------------------
+            # When 'range' is set with None elements on an axis object that
+            # has 'autorange', set autorange to the appropriate value so
+            # that plotly.js partial autoranging works correctly.
+            # Without this, plotly.js impliedEdits sets autorange=false when
+            # range is specified, preventing partial autorange behavior.
+            if "range" in update_obj and "autorange" in plotly_obj._valid_props:
+                if "autorange" in update_obj:
+                    # User explicitly provided autorange in the same update.
+                    # Re-apply it to ensure it takes precedence over any
+                    # implicit autorange set by the __setitem__ handler
+                    # for 'range'.
+                    plotly_obj["autorange"] = update_obj["autorange"]
+                else:
+                    range_val = update_obj["range"]
+                    if isinstance(range_val, (list, tuple)) and len(range_val) == 2:
+                        has_null_lower = range_val[0] is None
+                        has_null_upper = range_val[1] is None
+                        if has_null_lower and has_null_upper:
+                            plotly_obj["autorange"] = True
+                        elif has_null_lower:
+                            plotly_obj["autorange"] = "min"
+                        elif has_null_upper:
+                            plotly_obj["autorange"] = "max"
+
         elif isinstance(plotly_obj, tuple):
             if len(update_obj) == 0:
                 # Nothing to do
@@ -4930,6 +4958,23 @@ def __setitem__(self, prop, value):
                 # ### Handle simple property ###
                 else:
                     self._set_prop(prop, value)
+
+                # Handle partial autorange when 'range' is set directly
+                # with None elements on an axis object.
+                # When range contains a None (null) element, plotly.js
+                # should use partial autoranging, but its impliedEdits
+                # mechanism sets autorange=false when range is specified.
+                # We counteract this by explicitly setting autorange.
+                if prop == "range" and "autorange" in self._valid_props:
+                    if isinstance(value, (list, tuple)) and len(value) == 2:
+                        has_null_lower = value[0] is None
+                        has_null_upper = value[1] is None
+                        if has_null_lower and has_null_upper:
+                            self._set_prop("autorange", True)
+                        elif has_null_lower:
+                            self._set_prop("autorange", "min")
+                        elif has_null_upper:
+                            self._set_prop("autorange", "max")
             else:
                 # Make sure properties dict is initialized
                 self._init_props()

tests/test_core/test_update_objects/test_update_subplots.py

@@ -599,3 +599,69 @@ def test_update_subplot_overwrite(self):
             fig.layout.xaxis.to_plotly_json(),
             {"title": {"font": {"family": "Courier"}}},
         )
+
+
+class TestPartialAutorange(TestCase):
+    """Tests for automatic autorange setting when range contains None.
+
+    When a user sets range=[value, None] or range=[None, value], plotly.js
+    should use partial autoranging. However, plotly.js impliedEdits sets
+    autorange=false when range is specified. We counteract this by
+    explicitly setting autorange to the appropriate value.
+
+    See: https://github.com/plotly/plotly.py/issues/5536
+    """
+
+    def test_range_upper_none_sets_autorange_max(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(range=[0, None])
+        self.assertEqual(fig.layout.yaxis.autorange, "max")
+
+    def test_range_lower_none_sets_autorange_min(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(range=[None, 5])
+        self.assertEqual(fig.layout.yaxis.autorange, "min")
+
+    def test_range_both_none_sets_autorange_true(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(range=[None, None])
+        self.assertEqual(fig.layout.yaxis.autorange, True)
+
+    def test_range_no_none_does_not_set_autorange(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(range=[0, 10])
+        self.assertIsNone(fig.layout.yaxis.autorange)
+
+    def test_xaxis_range_with_none(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_xaxes(range=[None, 5])
+        self.assertEqual(fig.layout.xaxis.autorange, "min")
+
+    def test_explicit_autorange_overrides_implicit(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(range=[0, None], autorange="max reversed")
+        self.assertEqual(fig.layout.yaxis.autorange, "max reversed")
+
+    def test_explicit_autorange_dict_order_preserved(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_yaxes(**{"autorange": "max reversed", "range": [0, None]})
+        self.assertEqual(fig.layout.yaxis.autorange, "max reversed")
+
+    def test_direct_property_assignment(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.layout.yaxis.range = [0, None]
+        self.assertEqual(fig.layout.yaxis.autorange, "max")
+
+    def test_update_layout_yaxis_range(self):
+        fig = go.Figure()
+        fig.add_trace(go.Scatter(y=[0, 6]))
+        fig.update_layout(yaxis_range=[None, 5])
+        self.assertEqual(fig.layout.yaxis.autorange, "min")