FIX: Prevent warning when clearing axes with shared non-linear scale

Saumya · Saumya · commit 2321eabc6bcf · 2025-12-09T01:12:30.000+05:30
When clearing an axes (via cla() or clf()) that has a shared axis with a non-linear scale (e.g., log, logit), a warning was incorrectly generated: 'Attempt to set non-positive xlim on a log-scaled axis will be ignored.' This occurred because the clear operation set default limits (0, 1) with emit=True, causing the limits to propagate to shared axes that still had non-linear scales which reject these limits. Fixed by using emit=False when setting default limits during clear, preventing propagation to shared axes. Fixes #9970
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -1419,12 +1419,18 @@ def __clear(self):
             share = getattr(self, f"_share{name}")
             if share is not None:
                 getattr(self, f"share{name}")(share)
+                # Don't set default limits for shared axes - they will be
+                # synchronized from the shared axis and may have non-linear
+                # scales that would reject the (0, 1) default limits.
             else:
                 # Although the scale was set to linear as part of clear,
                 # polar requires that _set_scale is called again
                 if self.name == "polar":
                     axis._set_scale("linear")
-                axis._set_lim(0, 1, auto=True)
+                # Use emit=False to prevent propagating (0, 1) default limits
+                # to shared axes that may have non-linear scales (e.g., 'log')
+                # that would reject these limits and generate a warning.
+                axis._set_lim(0, 1, emit=False, auto=True)
         self._update_transScale()
 
         self.stale = True
