Merge pull request matplotlib#26300 from tacaswell/fix/multiple_tightlayout

Author: jklymak

lib/matplotlib/figure.py

@@ -3522,14 +3522,14 @@ def tight_layout(self, *, pad=1.08, h_pad=None, w_pad=None, rect=None):
         # note that here we do not permanently set the figures engine to
         # tight_layout but rather just perform the layout in place and remove
         # any previous engines.
-        engine = TightLayoutEngine(pad=pad, h_pad=h_pad, w_pad=w_pad,
-                                   rect=rect)
+        engine = TightLayoutEngine(pad=pad, h_pad=h_pad, w_pad=w_pad, rect=rect)
         try:
             previous_engine = self.get_layout_engine()
             self.set_layout_engine(engine)
             engine.execute(self)
-            if not isinstance(previous_engine, TightLayoutEngine) \
-                    and previous_engine is not None:
+            if previous_engine is not None and not isinstance(
+                previous_engine, (TightLayoutEngine, PlaceHolderLayoutEngine)
+            ):
                 _api.warn_external('The figure layout has changed to tight')
         finally:
             self.set_layout_engine('none')

lib/matplotlib/tests/test_figure.py

@@ -701,6 +701,14 @@ def test_layout_change_warning(layout):
         plt.tight_layout()
 
 
+def test_repeated_tightlayout():
+    fig = Figure()
+    fig.tight_layout()
+    # subsequent calls should not warn
+    fig.tight_layout()
+    fig.tight_layout()
+
+
 @check_figures_equal(extensions=["png", "pdf"])
 def test_add_artist(fig_test, fig_ref):
     fig_test.dpi = 100