Remove intent to deprecate rcParams["backend_fallback"].

anntzer · anntzer · commit 99a2e462c669 · 2018-09-05T15:29:28.000+02:00
I had left a note intending to deprecate this rcParam back when the
backend-switching API would let the user specify an explicit fallback
list.  As this feature was not accepted, it makes sense to keep the
rcparam.

Also move its actual use next to the place where the backend is set up
in pyplot.py.  Also move the call to install_repl_displayhook after
that, as install_repl_displayhook calls get_backend() so we want the
rcparam to have taken effect already.
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -72,26 +72,6 @@
 _log = logging.getLogger(__name__)
 
 
-## Backend detection ##
-
-
-# FIXME: Deprecate.
-def _backend_selection():
-    """
-    If rcParams['backend_fallback'] is true, we will check (at backend
-    load-time) to see if the current backend is compatible with the current
-    running event loop, and if not switches to a compatible one.
-    """
-    if rcParams["backend_fallback"]:
-        if (dict.__getitem__(rcParams, "backend") in _interactive_bk
-                and _get_running_interactive_framework()):
-            dict.__setitem__(
-                rcParams, "backend", rcsetup._auto_backend_sentinel)
-
-
-_backend_selection()
-
-
 ## Global ##
 
 
@@ -2348,16 +2328,23 @@ def _autogen_docstring(base):
     return lambda func: addendum(docstring.copy_dedent(base)(func))
 
 
-# just to be safe.  Interactive mode can be turned on without
+# If rcParams['backend_fallback'] is true, and an interactive backend is
+# requested, ignore rcParams['backend'] and force selection of a backend that
+# is compatible with the current running interactive framework.
+if (rcParams["backend_fallback"]
+        and dict.__getitem__(rcParams, "backend") in _interactive_bk
+        and _get_running_interactive_framework()):
+    dict.__setitem__(rcParams, "backend", rcsetup._auto_backend_sentinel)
+# Set up the backend.
+switch_backend(rcParams["backend"])
+
+# Just to be safe.  Interactive mode can be turned on without
 # calling `plt.ion()` so register it again here.
 # This is safe because multiple calls to `install_repl_displayhook`
 # are no-ops and the registered function respect `mpl.is_interactive()`
 # to determine if they should trigger a draw.
 install_repl_displayhook()
 
-# Set up the backend.
-switch_backend(rcParams["backend"])
-
 
 ################# REMAINING CONTENT GENERATED BY boilerplate.py ##############
 
