Deprecate the backend.qt{4,5} rcParams.

anntzer · anntzer · commit 188a4af7a9b7 · 2018-01-21T22:07:17.000-08:00
1) For the rcParams rewrite (MEP32), they may make it tricky to
transform rcParams into a nested dictionary type of object, as "backend"
is already the name of another (more important) rcParam.  This specific
issue could be solved with deprecation + renaming, but also...

2) The use of these rcParams can easily be replaced by a) first
importing one of the bindings (qt_compat will ensure that the already
imported binding gets used, as importing multiple bindings in the same
process is a bad idea anyways), or b) setting the QT_API environment
variable appropriately.
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
@@ -1116,8 +1116,10 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
         return config_from_file
 
     iter_params = six.iteritems(defaultParams)
-    config = RcParams([(key, default) for key, (default, _) in iter_params
-                                      if key not in _all_deprecated])
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", mplDeprecation)
+        config = RcParams([(key, default) for key, (default, _) in iter_params
+                           if key not in _all_deprecated])
     config.update(config_from_file)
 
     if config['datapath'] is None:
@@ -1155,9 +1157,11 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
 
 rcParamsOrig = rcParams.copy()
 
-rcParamsDefault = RcParams([(key, default) for key, (default, converter) in
-                            six.iteritems(defaultParams)
-                            if key not in _all_deprecated])
+with warnings.catch_warnings():
+    warnings.simplefilter("ignore", mplDeprecation)
+    rcParamsDefault = RcParams([(key, default) for key, (default, converter) in
+                                six.iteritems(defaultParams)
+                                if key not in _all_deprecated])
 
 rcParams['ps.usedistiller'] = checkdep_ps_distiller(
                       rcParams['ps.usedistiller'])
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -266,8 +266,20 @@ def validate_backend(s):
         return _validate_standard_backends(s)
 
 
-validate_qt4 = ValidateInStrings('backend.qt4', ['PyQt4', 'PySide', 'PyQt4v2'])
-validate_qt5 = ValidateInStrings('backend.qt5', ['PyQt5', 'PySide2'])
+@deprecated("2.2",
+            "The backend.qt4 rcParam was deprecated in version 2.2.  In order "
+            "to force the use of a specific Qt4 binding, either import that "
+            "binding first, or set the QT_API environment variable.")
+def validate_qt4(s):
+    return ValidateInStrings("backend.qt4", ['PyQt4', 'PySide', 'PyQt4v2'])(s)
+
+
+@deprecated("2.2",
+            "The backend.qt5 rcParam was deprecated in version 2.2.  In order "
+            "to force the use of a specific Qt5 binding, either import that "
+            "binding first, or set the QT_API environment variable.")
+def validate_qt5(s):
+    return ValidateInStrings("backend.qt5", ['PyQt5', 'PySide2'])(s)
 
 
 def validate_toolbar(s):
