fix histogram marginal/facet rule order

Author: nicolaskruchten

packages/python/plotly/plotly/express/_core.py

@@ -924,13 +924,6 @@ def apply_default_cascade(args):
                 "longdashdot",
             ]
 
-    # If both marginals and faceting are specified, faceting wins
-    if args.get("facet_col", None) is not None and args.get("marginal_y", None):
-        args["marginal_y"] = None
-
-    if args.get("facet_row", None) is not None and args.get("marginal_x", None):
-        args["marginal_x"] = None
-
 
 def _check_name_not_reserved(field_name, reserved_names):
     if field_name not in reserved_names:
@@ -1775,6 +1768,14 @@ def infer_config(args, constructor, trace_patch, layout_patch):
         args[position] = args["marginal"]
         args[other_position] = None
 
+    # If both marginals and faceting are specified, faceting wins
+    if args.get("facet_col", None) is not None and args.get("marginal_y", None):
+        args["marginal_y"] = None
+
+    if args.get("facet_row", None) is not None and args.get("marginal_x", None):
+        args["marginal_x"] = None
+
+    # facet_col_wrap only works if no marginals or row faceting is used
     if (
         args.get("marginal_x", None) is not None
         or args.get("marginal_y", None) is not None

packages/python/plotly/plotly/tests/test_core/test_px/test_facets.py

@@ -51,8 +51,13 @@ def test_facets_with_marginals():
 
     fig = px.histogram(df, x="total_bill", facet_col="sex", marginal="rug")
     assert len(fig.data) == 4
-    # fig = px.histogram(df, x="total_bill", facet_row="sex", marginal="rug")
-    # assert len(fig.data) == 2 buggy
+    fig = px.histogram(df, x="total_bill", facet_row="sex", marginal="rug")
+    assert len(fig.data) == 2
+
+    fig = px.histogram(df, y="total_bill", facet_col="sex", marginal="rug")
+    assert len(fig.data) == 2
+    fig = px.histogram(df, y="total_bill", facet_row="sex", marginal="rug")
+    assert len(fig.data) == 4
 
     fig = px.scatter(df, x="total_bill", y="tip", facet_col="sex", marginal_x="rug")
     assert len(fig.data) == 4