Version gate instead of ignoring, fix PDF to always properly close empty files

Author: ksunden

lib/matplotlib/backends/backend_pdf.py

@@ -2708,6 +2708,7 @@ def __enter__(self):
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
+        print(f"Closing file {self._filename}")
         self.close()
 
     def _ensure_file(self):
@@ -2728,7 +2729,7 @@ def close(self):
             _api.warn_deprecated("3.8", message=(
                 "Keeping empty pdf files is deprecated since %(since)s and support "
                 "will be removed %(removal)s."))
-            PdfFile(self._filename, metadata=self._metadata)  # touch the file.
+            PdfFile(self._filename, metadata=self._metadata).close()  # touch the file.
 
     def infodict(self):
         """

lib/matplotlib/tests/test_backend_pdf.py

@@ -3,7 +3,6 @@
 import io
 import os
 from pathlib import Path
-import warnings
 
 import numpy as np
 import pytest
@@ -85,44 +84,40 @@ def test_multipage_keep_empty(tmp_path):
     os.chdir(tmp_path)
 
     # test empty pdf files
-    # Due to order of `with` block execution, a warning for unclosed file is raised
-    # but the pytest.warns must happen before the PdfPages is created
-    with warnings.catch_warnings():
-        warnings.filterwarnings("ignore", category=ResourceWarning)
-
-        # an empty pdf is left behind with keep_empty unset
-        with pytest.warns(mpl.MatplotlibDeprecationWarning), PdfPages("a.pdf") as pdf:
-            pass
-        assert os.path.exists("a.pdf")
-
-        # an empty pdf is left behind with keep_empty=True
-        with pytest.warns(mpl.MatplotlibDeprecationWarning), \
-                PdfPages("b.pdf", keep_empty=True) as pdf:
-            pass
-        assert os.path.exists("b.pdf")
-
-        # an empty pdf deletes itself afterwards with keep_empty=False
-        with PdfPages("c.pdf", keep_empty=False) as pdf:
-            pass
-        assert not os.path.exists("c.pdf")
-
-        # test pdf files with content, they should never be deleted
-
-        # a non-empty pdf is left behind with keep_empty unset
-        with PdfPages("d.pdf") as pdf:
-            pdf.savefig(plt.figure())
-        assert os.path.exists("d.pdf")
-
-        # a non-empty pdf is left behind with keep_empty=True
-        with pytest.warns(mpl.MatplotlibDeprecationWarning), \
-                PdfPages("e.pdf", keep_empty=True) as pdf:
-            pdf.savefig(plt.figure())
-        assert os.path.exists("e.pdf")
-
-        # a non-empty pdf is left behind with keep_empty=False
-        with PdfPages("f.pdf", keep_empty=False) as pdf:
-            pdf.savefig(plt.figure())
-        assert os.path.exists("f.pdf")
+
+    # an empty pdf is left behind with keep_empty unset
+    with pytest.warns(mpl.MatplotlibDeprecationWarning), PdfPages("a.pdf") as pdf:
+        pass
+    assert os.path.exists("a.pdf")
+
+    # an empty pdf is left behind with keep_empty=True
+    with pytest.warns(mpl.MatplotlibDeprecationWarning), \
+            PdfPages("b.pdf", keep_empty=True) as pdf:
+        pass
+    assert os.path.exists("b.pdf")
+
+    # an empty pdf deletes itself afterwards with keep_empty=False
+    with PdfPages("c.pdf", keep_empty=False) as pdf:
+        pass
+    assert not os.path.exists("c.pdf")
+
+    # test pdf files with content, they should never be deleted
+
+    # a non-empty pdf is left behind with keep_empty unset
+    with PdfPages("d.pdf") as pdf:
+        pdf.savefig(plt.figure())
+    assert os.path.exists("d.pdf")
+
+    # a non-empty pdf is left behind with keep_empty=True
+    with pytest.warns(mpl.MatplotlibDeprecationWarning), \
+            PdfPages("e.pdf", keep_empty=True) as pdf:
+        pdf.savefig(plt.figure())
+    assert os.path.exists("e.pdf")
+
+    # a non-empty pdf is left behind with keep_empty=False
+    with PdfPages("f.pdf", keep_empty=False) as pdf:
+        pdf.savefig(plt.figure())
+    assert os.path.exists("f.pdf")
 
 
 def test_composite_image():

lib/matplotlib/tests/test_colors.py

@@ -1,7 +1,7 @@
 import copy
 import itertools
 import unittest.mock
-import warnings
+from packaging.version import parse as parse_version
 
 from io import BytesIO
 import numpy as np
@@ -149,10 +149,12 @@ def test_double_register_builtin_cmap():
         with pytest.warns(mpl.MatplotlibDeprecationWarning):
             cm.register_cmap(name, mpl.colormaps[name])
 
-    with warnings.catch_warnings():
-        warnings.filterwarnings("ignore", category=mpl.MatplotlibDeprecationWarning)
+    if parse_version(pytest.__version__).major < 8:
         with pytest.warns(UserWarning):
             cm.register_cmap(name, mpl.colormaps[name], override_builtin=True)
+    else:
+        with pytest.warns(UserWarning), pytest.warns(mpl.MatplotlibDeprecationWarning):
+            cm.register_cmap(name, mpl.colormaps[name], override_builtin=True)
 
 
 def test_unregister_builtin_cmap():

lib/matplotlib/tests/test_ticker.py

@@ -3,7 +3,7 @@
 import locale
 import logging
 import re
-import warnings
+from packaging.version import parse as parse_version
 
 import numpy as np
 from numpy.testing import assert_almost_equal, assert_array_equal
@@ -915,16 +915,17 @@ def test_mathtext_ticks(self):
             'axes.formatter.use_mathtext': False
         })
 
-        # Glyph warning unrelated
-        with warnings.catch_warnings():
-            warnings.filterwarnings(
-                "ignore", category=UserWarning, message="Glyph 8722"
-            )
-
+        if parse_version(pytest.__version__).major < 8:
             with pytest.warns(UserWarning, match='cmr10 font should ideally'):
                 fig, ax = plt.subplots()
                 ax.set_xticks([-1, 0, 1])
                 fig.canvas.draw()
+        else:
+            with (pytest.warns(UserWarning, match="Glyph 8722"),
+                  pytest.warns(UserWarning, match='cmr10 font should ideally')):
+                fig, ax = plt.subplots()
+                ax.set_xticks([-1, 0, 1])
+                fig.canvas.draw()
 
     def test_cmr10_substitutions(self, caplog):
         mpl.rcParams.update({