Emit xlim_changed on shared axes.

anntzer · anntzer · commit 9887650e5a4e · 2023-05-30T15:45:44.000+02:00
diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
@@ -2,6 +2,7 @@
 Classes for the ticks and x- and y-axis.
 """
 
+import dataclasses
 import datetime
 import functools
 import logging
@@ -32,6 +33,8 @@
 _gridline_param_names = ['grid_' + name
                          for name in _line_param_names + _line_param_aliases]
 
+_NoRecursionMarker = dataclasses.make_dataclass("_NoRecursionMarker", ["event_src"])
+
 
 class Tick(martist.Artist):
     """
@@ -1225,13 +1228,17 @@ def _set_lim(self, v0, v1, *, emit=True, auto):
         if auto is not None:
             self._set_autoscale_on(bool(auto))
 
-        if emit:
+        # Undocumented internal feature: emit can be set to _NoRecursionMarker(self),
+        # which is treated as True but avoids infinite recursion.
+        if emit and emit != _NoRecursionMarker(self):
             self.axes.callbacks.process(f"{name}lim_changed", self.axes)
             # Call all of the other axes that are shared with this one
             for other in self._get_shared_axes():
                 if other is not self.axes:
+                    if not isinstance(emit, _NoRecursionMarker):
+                        emit = _NoRecursionMarker(self)
                     other._axis_map[name]._set_lim(
-                        v0, v1, emit=False, auto=auto)
+                        v0, v1, emit=emit, auto=auto)
                     if other.figure != self.figure:
                         other.figure.canvas.draw_idle()
 
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -8704,3 +8704,12 @@ def test_tick_param_labelfont():
     plt.title('Title in sans-serif')
     for text in ax.get_xticklabels():
         assert text.get_fontfamily()[0] == 'monospace'
+
+
+def test_xylim_changed_shared():
+    fig, axs = plt.subplots(2, sharex=True, sharey=True)
+    events = []
+    axs[1].callbacks.connect("xlim_changed", events.append)
+    axs[1].callbacks.connect("ylim_changed", events.append)
+    axs[0].set(xlim=[1, 3], ylim=[2, 4])
+    assert events == [axs[1], axs[1]]
