Fix ArtistInspector.get_aliases.

anntzer · anntzer · commit e74a74326ebc · 2018-09-06T11:28:17.000+02:00
The docstring parsing in get_aliases was brittle and didn't handle the final dot that cbook._define_aliases added to the docstring, so as of master it would return the keys with an additional dot. Instead, use a regex which will loudly error out if the format is incorrect. Also replace {key: None, ...} mapping simulating a set to, well, a set. (The use of sets instead of lists was added in ed9c2b5 apparently to handle the case where the same alias is added twice.) (Yes, the whole alias machinery could now be simplified e.g. by adding an `is_mpl_alias` attribute on the aliases instead.)
diff --git a/doc/users/next_whats_new/2018-09-06-AL.rst b/doc/users/next_whats_new/2018-09-06-AL.rst
@@ -0,0 +1,10 @@
+Return type of ArtistInspector.get_aliases changed
+``````````````````````````````````````````````````
+
+`ArtistInspector.get_aliases` previously returned the set of aliases as
+``{fullname: {alias1: None, alias2: None, ...}}``.  The dict-to-None mapping
+was used to simulate a set in earlier versions of Python.  It has now been
+replaced by a set, i.e. ``{fullname: {alias1, alias2, ...}}``.
+
+This value is also stored in `ArtistInspector.aliasd`, which has likewise
+changed.
diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
@@ -1189,15 +1189,14 @@ def __init__(self, o):
 
     def get_aliases(self):
         """
-        Get a dict mapping *fullname* -> *alias* for each *alias* in
-        the :class:`~matplotlib.artist.ArtistInspector`.
+        Get a dict mapping property fullnames to sets of aliases for each alias
+        in the :class:`~matplotlib.artist.ArtistInspector`.
 
         e.g., for lines::
 
-          {'markerfacecolor': 'mfc',
-           'linewidth'      : 'lw',
+          {'markerfacecolor': {'mfc'},
+           'linewidth'      : {'lw'},
           }
-
         """
         names = [name for name in dir(self.o)
                  if name.startswith(('set_', 'get_'))
@@ -1207,9 +1206,9 @@ def get_aliases(self):
             func = getattr(self.o, name)
             if not self.is_alias(func):
                 continue
-            docstring = func.__doc__
-            fullname = docstring.replace('`', '')[10:]
-            aliases.setdefault(fullname[4:], {})[name[4:]] = None
+            propname = re.search("`({}.*)`".format(name[:4]),  # get_.*/set_.*
+                                 func.__doc__).group(1)
+            aliases.setdefault(propname, set()).add(name[4:])
         return aliases
 
     _get_valid_values_regex = re.compile(
diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
@@ -30,7 +30,7 @@
 # allows all Line2D kwargs.
 _line_AI = artist.ArtistInspector(mlines.Line2D)
 _line_param_names = _line_AI.get_setters()
-_line_param_aliases = [list(d.keys())[0] for d in _line_AI.aliasd.values()]
+_line_param_aliases = [list(d)[0] for d in _line_AI.aliasd.values()]
 _gridline_param_names = ['grid_' + name
                          for name in _line_param_names + _line_param_aliases]
 
