matplotlib · ksunden · Sep 27, 2023 · Sep 26, 2023 · ksunden · Sep 26, 2023
diff --git a/doc/api/next_api_changes/behavior/26902-RP.rst b/doc/api/next_api_changes/behavior/26902-RP.rst
@@ -0,0 +1,5 @@
+``Line2D``
+~~~~~~~~~~
+
+When creating a Line2D or using `.Line2D.set_xdata` and `.Line2D.set_ydata`,
+passing x/y data as non sequence is now an error.
-passing x/y data as non sequence is now an error.
+passing x/y data as non sequence is now an error.
+
-passing x/y data as non sequence is now an error.
+passing x/y data as non sequence is now an error.
+
diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
@@ -1276,14 +1276,7 @@ def set_xdata(self, x):
         x : 1D array
         """
         if not np.iterable(x):
-            # When deprecation cycle is completed
-            # raise RuntimeError('x must be a sequence')
-            _api.warn_deprecated(
-                since="3.7",
-                message="Setting data with a non sequence type "
-                "is deprecated since %(since)s and will be "
-                "remove %(removal)s")
-            x = [x, ]
+            raise RuntimeError('x must be a sequence')
         self._xorig = copy.copy(x)
         self._invalidx = True
         self.stale = True
@@ -1297,14 +1290,7 @@ def set_ydata(self, y):
         y : 1D array
         """
         if not np.iterable(y):
-            # When deprecation cycle is completed
-            # raise RuntimeError('y must be a sequence')
-            _api.warn_deprecated(
-                since="3.7",
-                message="Setting data with a non sequence type "
-                "is deprecated since %(since)s and will be "
-                "remove %(removal)s")
-            y = [y, ]
+            raise RuntimeError('y must be a sequence')
         self._yorig = copy.copy(y)
         self._invalidy = True
         self.stale = True

diff --git a/lib/matplotlib/tests/test_lines.py b/lib/matplotlib/tests/test_lines.py
@@ -92,12 +92,9 @@ def test_invalid_line_data():
         mlines.Line2D([], 1)
 
     line = mlines.Line2D([], [])
-    # when deprecation cycle is completed
-    # with pytest.raises(RuntimeError, match='x must be'):
-    with pytest.warns(mpl.MatplotlibDeprecationWarning):
+    with pytest.raises(RuntimeError, match='x must be'):
         line.set_xdata(0)
-    # with pytest.raises(RuntimeError, match='y must be'):
-    with pytest.warns(mpl.MatplotlibDeprecationWarning):
+    with pytest.raises(RuntimeError, match='y must be'):
         line.set_ydata(0)