FIX: catplot with redundant hue assignment creates empty legend with …

…title #3537

seaborn/categorical.py

@@ -409,12 +409,10 @@ def _invert_scale(self, ax, data, vars=("x", "y")):
                     data[col] = inv(data[col])
 
     def _configure_legend(self, ax, func, common_kws=None, semantic_kws=None):
-
         if self.legend == "auto":
             show_legend = not self._redundant_hue and self.input_format != "wide"
         else:
             show_legend = bool(self.legend)
-
         if show_legend:
             self.add_legend_data(ax, func, common_kws, semantic_kws=semantic_kws)
             handles, _ = ax.get_legend_handles_labels()
@@ -3095,21 +3093,12 @@ def catplot(
         g._update_legend_data(ax)
         ax.legend_ = None
 
-    if legend and "hue" in p.variables and p.input_format == "long":
-        # Obtaining the column names for hue, x, and y.
-        hue_value = p.variables.get("hue")
-        x_value = p.variables.get("x")
-        y_value = p.variables.get("y")
-        # Obtaining the datatype of hue
-        hue_type = p.var_types.get("hue")
-        if legend == 'auto' and hue_value in {x_value, y_value} \
-                and hue_type != 'numeric':
-            # Setting the title of hue to None if hue matches "x" or
-            # "y", or if the data type of "hue" is numeric.
-            title_hue = None
-        else:
-            title_hue = hue_value
-        g.add_legend(title=title_hue, label_order=hue_order)
+    if legend == "auto":
+        show_legend = not p._redundant_hue and p.input_format != "wide"
+    else:
+        show_legend = bool(legend)
+    if show_legend:
+        g.add_legend(title=p.variables.get("hue"), label_order=hue_order)
 
     if data is not None:
         # Replace the dataframe on the FacetGrid for any subsequent maps