Merge pull request matplotlib#25870 from turnipseason/bug-fix-for-issue-23770

Adds error handling around install_repl_displayhook

Author: tacaswell

lib/matplotlib/pyplot.py

@@ -520,7 +520,11 @@ def draw_if_interactive() -> None:
     matplotlib.backends.backend = newbackend  # type: ignore[attr-defined]
 
     # Make sure the repl display hook is installed in case we become interactive.
-    install_repl_displayhook()
+    try:
+        install_repl_displayhook()
+    except NotImplementedError as err:
+        _log.warning("Fallback to a different backend")
+        raise ImportError from err
 
 
 def _warn_if_gui_out_of_main_thread() -> None:

lib/matplotlib/tests/test_backends_interactive.py

@@ -629,6 +629,21 @@ def test_blitting_events(env):
     assert 0 < ndraws < 5
 
 
+def _fallback_check():
+    import IPython.core.interactiveshell as ipsh
+    import matplotlib.pyplot
+    ipsh.InteractiveShell.instance()
+    matplotlib.pyplot.figure()
+
+
+def test_fallback_to_different_backend():
+    pytest.importorskip("IPython")
+    # Runs the process that caused the GH issue 23770
+    # making sure that this doesn't crash
+    # since we're supposed to be switching to a different backend instead.
+    response = _run_helper(_fallback_check, timeout=_test_timeout)
+
+
 def _impl_test_interactive_timers():
     # A timer with <1 millisecond gets converted to int and therefore 0
     # milliseconds, which the mac framework interprets as singleshot.