Deprecate more rc validators.

anntzer · anntzer · commit 37c762059209 · 2020-02-29T15:03:01.000+01:00
- validate_bool_maybe_none is now unused; if we really need it back
  we'd make it private and I'd anyways rather add machinery so that
  one can just specify it as `[bool, None]` (or `Optional[bool]`) in
  _prop_validators.
- validate_hinting will become a plain list after the deprecation
  period.
- validate_movie_writer makes it impossible to set movie.writer to
  a third-party animation writer, because that third-party module
  will necessarily first import matplotlib before being able to
  register its writer, and thus the matplotlibrc file will be parsed
  before the writer is registered.  In any case,
  `MovieWriterRegistry.__getitem__` also raises an informative error
  on unknown writer names, which should be enough, so let's just
  accept any string.
diff --git a/doc/api/next_api_changes/deprecations.rst b/doc/api/next_api_changes/deprecations.rst
@@ -220,9 +220,11 @@ The following validators, defined in `.rcsetup`, are deprecated:
 ``validate_movie_frame_fmt``, ``validate_axis_locator``,
 ``validate_movie_html_fmt``, ``validate_grid_axis``,
 ``validate_axes_titlelocation``, ``validate_toolbar``,
-``validate_ps_papersize``, ``validate_legend_log``.  To test whether an rcParam
-value would be acceptable, one can test e.g. ``rc = RcParams(); rc[k] = v``
-raises an exception.
+``validate_ps_papersize``, ``validate_legend_loc``,
+``validate_bool_maybe_none``, ``validate_hinting``,
+``validate_movie_writers``.
+To test whether an rcParam value would be acceptable, one can test e.g. ``rc =
+RcParams(); rc[k] = v`` raises an exception.
 
 Toggling axes navigation from the keyboard using "a" and digit keys
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -140,6 +140,7 @@ def validate_bool(b):
         raise ValueError('Could not convert "%s" to bool' % b)
 
 
+@cbook.deprecated("3.3")
 def validate_bool_maybe_none(b):
     """Convert b to ``bool`` or raise, passing through *None*."""
     if isinstance(b, str):
@@ -646,7 +647,13 @@ def validate_markevery(s):
     'svg.fonttype', ['none', 'path'], _deprecated_since="3.3")
 
 
+@cbook.deprecated("3.3")
 def validate_hinting(s):
+    return _validate_hinting(s)
+
+
+# Replace by plain list in _prop_validators after deprecation period.
+def _validate_hinting(s):
     if s in (True, False):
         cbook.warn_deprecated(
             "3.2", message="Support for setting the text.hinting rcParam to "
@@ -663,6 +670,7 @@ def validate_hinting(s):
     _deprecated_since="3.3")
 
 
+@cbook.deprecated("3.3")
 def validate_movie_writer(s):
     # writers.list() would only list actually available writers, but
     # FFMpeg.isAvailable is slow and not worth paying for at every import.
@@ -1133,7 +1141,7 @@ def _convert_validator_spec(key, conv):
     'text.usetex':         [False, validate_bool],
     'text.latex.preamble': ['', _validate_tex_preamble],
     'text.latex.preview':  [False, validate_bool],
-    'text.hinting':        ['auto', validate_hinting],
+    'text.hinting':        ['auto', _validate_hinting],
     'text.hinting_factor': [8, validate_int],
     'text.kerning_factor': [0, validate_int],
     'text.antialiased':    [True, validate_bool],
@@ -1452,7 +1460,7 @@ def _convert_validator_spec(key, conv):
     # Limit, in MB, of size of base64 encoded animation in HTML
     # (i.e. IPython notebook)
     'animation.embed_limit':  [20, validate_float],
-    'animation.writer':       ['ffmpeg', validate_movie_writer],
+    'animation.writer':       ['ffmpeg', validate_string],
     'animation.codec':        ['h264', validate_string],
     'animation.bitrate':      [-1, validate_int],
     # Controls image format when frames are written to disk
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -125,9 +125,8 @@ def test_Bug_2543():
         # real test is that this does not raise
         assert validate_bool_maybe_none(None) is None
         assert validate_bool_maybe_none("none") is None
-
-    with pytest.raises(ValueError):
-        validate_bool_maybe_none("blah")
+        with pytest.raises(ValueError):
+            validate_bool_maybe_none("blah")
     with pytest.raises(ValueError):
         validate_bool(None)
     with pytest.raises(ValueError):
