DOC: Add missing API change docs for 1.5.3

tacaswell · tacaswell · commit 7f55b9edc4d6 · 2016-10-11T21:47:49.000-04:00
closes #7218
diff --git a/doc/api/api_changes.rst b/doc/api/api_changes.rst
@@ -11,6 +11,34 @@ sources of the changes you are experiencing.
 For new features that were added to matplotlib, please see
 :ref:`whats-new`.
 
+Changes in 1.5.3
+================
+
+``ax.plot(..., marker=None)`` gives default marker
+--------------------------------------------------
+
+Prior to 1.5.3 kwargs passed to `~matplotlib.Axes.plot` were handled
+in two parts -- default kwargs generated internal to
+`~matplotlib.Axes.plot` (such as the cycled styles) and user supplied
+kwargs.  The internally generated kwargs were passed to the
+`~matplotlib.lines.Line2D.__init__` and the user kwargs were passed to
+``ln.set(**kwargs)`` to update the artist after it was created.  Now
+both sets of kwargs are merged and passed to
+`~matplotlib.lines.Line2D.__init__`.  This change was made to allow `None`
+to be passed in via the user kwargs to mean 'do the default thing'  as
+is the convention through out mpl rather than raising an exception.
+
+Unlike most `~matplotlib.lines.Line2D` setter methods
+`~matplotlib.lines.Line2D.set_marker` did accept `None` as a valid
+input which was mapped to 'no marker'.  Thus, by routing this
+``marker=None`` through ``__init__`` rather than ``set(...)`` the meaning
+of ``ax.plot(..., marker=None)`` changed from 'no markers' to 'default markers
+from rcparams'.
+
+This is change in only evident if ``mpl.rcParams['lines.marker']`` has a value
+other than ``'None'`` (which is string ``'None'`` which means 'no marker').
+
+
 Changes in 1.5.2
 ================
 
