Fix spacing issue in _spacing function

seaborn/_core/plot.py

@@ -1450,7 +1450,10 @@ def get_order(var):
                         view_width = view_df["width"]
                     else:
                         view_width = 0.8  # TODO what default?
-                    spacing = scales[orient]._spacing(view_df.loc[view_idx, orient])
+                    spacing = scales[orient]._spacing(
+                        view_df.loc[view_idx, orient],
+                        groupby=view_df["group"]  
+                    )
                     width.loc[view_idx] = view_width * spacing
                 df["width"] = width
 

seaborn/_core/scales.py

@@ -95,13 +95,16 @@ def set_default_locators_and_formatters(self, axis):
 
         return InternalScale(name, (forward, inverse))
 
-    def _spacing(self, x: Series) -> float:
-        space = self._spacer(x)
-        if np.isnan(space):
-            # This happens when there is no variance in the orient coordinate data
-            # Not exactly clear what the right default is, but 1 seems reasonable?
-            return 1
-        return space
+    def _spacing(self, x: Series, groupby: Optional[Series] = None) -> float:
+        if groupby is not None:
+            grouped = x.groupby(groupby)
+            spaces = grouped.apply(lambda group: self._spacer(group))
+            return spaces.min() 
+        else:
+            space = self._spacer(x)
+            if np.isnan(space):
+                return 1
+            return space
 
     def _setup(
         self, data: Series, prop: Property, axis: Axis | None = None,