Merge pull request matplotlib#25810 from QuLogic/fix-default-collection-style

Fix default return of Collection.get_{cap,join}style

Author: greglucas

lib/matplotlib/collections.py

@@ -641,8 +641,16 @@ def set_capstyle(self, cs):
         """
         self._capstyle = CapStyle(cs)
 
+    @_docstring.interpd
     def get_capstyle(self):
-        return self._capstyle.name
+        """
+        Return the cap style for the collection (for all its elements).
+
+        Returns
+        -------
+        %(CapStyle)s or None
+        """
+        return self._capstyle.name if self._capstyle else None
 
     @_docstring.interpd
     def set_joinstyle(self, js):
@@ -655,8 +663,16 @@ def set_joinstyle(self, js):
         """
         self._joinstyle = JoinStyle(js)
 
+    @_docstring.interpd
     def get_joinstyle(self):
-        return self._joinstyle.name
+        """
+        Return the join style for the collection (for all its elements).
+
+        Returns
+        -------
+        %(JoinStyle)s or None
+        """
+        return self._joinstyle.name if self._joinstyle else None
 
     @staticmethod
     def _bcast_lwls(linewidths, dashes):

lib/matplotlib/collections.pyi

@@ -51,9 +51,9 @@ class Collection(artist.Artist, cm.ScalarMappable):
     def set_linewidth(self, lw: float | Sequence[float]) -> None: ...
     def set_linestyle(self, ls: LineStyleType | Sequence[LineStyleType]) -> None: ...
     def set_capstyle(self, cs: CapStyleType) -> None: ...
-    def get_capstyle(self) -> Literal["butt", "projecting", "round"]: ...
+    def get_capstyle(self) -> Literal["butt", "projecting", "round"] | None: ...
     def set_joinstyle(self, js: JoinStyleType) -> None: ...
-    def get_joinstyle(self) -> Literal["miter", "round", "bevel"]: ...
+    def get_joinstyle(self) -> Literal["miter", "round", "bevel"] | None: ...
     def set_antialiased(self, aa: bool | Sequence[bool]) -> None: ...
     def get_antialiased(self) -> NDArray[np.bool_]: ...
     def set_color(self, c: ColorType | Sequence[ColorType]) -> None: ...

lib/matplotlib/tests/test_collections.py

@@ -625,6 +625,8 @@ def test_set_wrong_linestyle():
 
 @mpl.style.context('default')
 def test_capstyle():
+    col = mcollections.PathCollection([])
+    assert col.get_capstyle() is None
     col = mcollections.PathCollection([], capstyle='round')
     assert col.get_capstyle() == 'round'
     col.set_capstyle('butt')
@@ -633,6 +635,8 @@ def test_capstyle():
 
 @mpl.style.context('default')
 def test_joinstyle():
+    col = mcollections.PathCollection([])
+    assert col.get_joinstyle() is None
     col = mcollections.PathCollection([], joinstyle='round')
     assert col.get_joinstyle() == 'round'
     col.set_joinstyle('miter')