matplotlib · rcomer · Feb 4, 2026 · Feb 5, 2026 · Feb 6, 2026 · Feb 6, 2026
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -47,34 +47,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - name-suffix: "(Minimum Versions)"
-            os: ubuntu-22.04
-            python-version: '3.11'
-            extra-requirements: '-c requirements/testing/minver.txt'
-            delete-font-cache: true
-            # https://github.com/matplotlib/matplotlib/issues/29844
-            pygobject-ver: '<3.52.0'
-          - os: ubuntu-22.04
-            python-version: '3.11'
-            CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
-            extra-requirements: '-r requirements/testing/extra.txt'
-            # https://github.com/matplotlib/matplotlib/issues/29844
-            pygobject-ver: '<3.52.0'
-          - name-suffix: "(Extra TeX packages)"
-            os: ubuntu-22.04
-            python-version: '3.13'
-            extra-packages: 'texlive-fonts-extra texlive-lang-cyrillic'
-            # https://github.com/matplotlib/matplotlib/issues/29844
-            pygobject-ver: '<3.52.0'
-          - name-suffix: "Free-threaded"
-            os: ubuntu-22.04
-            python-version: '3.13t'
-            # https://github.com/matplotlib/matplotlib/issues/29844
-            pygobject-ver: '<3.52.0'
-          - os: ubuntu-24.04
-            python-version: '3.12'
-          - os: ubuntu-24.04
-            python-version: '3.14'
           - os: ubuntu-24.04-arm
             python-version: '3.12'
           - os: macos-14  # This runner is on M1 (arm64) chips.
@@ -336,7 +308,7 @@ jobs:
           if [[ "${{ matrix.python-version }}" == '3.13t' ]]; then
             export PYTHON_GIL=0
           fi
-          pytest -rfEsXR -n auto \
+          pytest -vrfEsXR -n 2 -m starts_subprocess\
             --maxfail=50 --timeout=300 --durations=25 \
             --cov-report=xml --cov=lib --log-level=DEBUG --color=yes
 

diff --git a/azure-pipelines.yml b/azure-pipelines.yml
@@ -120,7 +120,7 @@ stages:
 
               echo "##vso[task.setvariable variable=VS_COVERAGE_TOOL]$TOOL"
 
-              PYTHONFAULTHANDLER=1 pytest -rfEsXR -n 2 \
+              PYTHONFAULTHANDLER=1 pytest -vrfEsXR -n 2 \
                   --maxfail=50 --timeout=300 --durations=25 \
                   --junitxml=junit/test-results.xml --cov-report=xml --cov=lib
 

diff --git a/lib/matplotlib/dviread.py b/lib/matplotlib/dviread.py
@@ -23,10 +23,9 @@
 import os
 import re
 import struct
-import subprocess
 import sys
 from collections import namedtuple
-from functools import cache, cached_property, lru_cache, partial, wraps
+from functools import cached_property, lru_cache, partial, wraps
 from pathlib import Path
 
 import fontTools.agl
@@ -1244,31 +1243,6 @@ def _parse_enc(path):
         raise ValueError(f"Failed to parse {path} as Postscript encoding")
 
 
-class _LuatexKpsewhich:
-    @cache  # A singleton.
-    def __new__(cls):
-        self = object.__new__(cls)
-        self._proc = self._new_proc()
-        return self
-
-    def _new_proc(self):
-        return subprocess.Popen(
-            ["luatex", "--luaonly", str(cbook._get_data_path("kpsewhich.lua"))],
-            # mktexpk logs to stderr; suppress that.
-            stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL,
-            # Store generated pk fonts in our own cache.
-            env={"MT_VARTEXFONTS": str(Path(mpl.get_cachedir(), "vartexfonts")),
-                 **os.environ})
-
-    def search(self, filename):
-        if self._proc.poll() is not None:  # Dead, restart it.
-            self._proc = self._new_proc()
-        self._proc.stdin.write(os.fsencode(filename) + b"\n")
-        self._proc.stdin.flush()
-        out = self._proc.stdout.readline().rstrip()
-        return None if out == b"nil" else os.fsdecode(out)
-
-
 @lru_cache
 def find_tex_file(filename):
     """
@@ -1295,10 +1269,7 @@ def find_tex_file(filename):
     if isinstance(filename, bytes):
         filename = filename.decode('utf-8', errors='replace')
 
-    try:
-        lk = _LuatexKpsewhich()
-    except FileNotFoundError:
-        lk = None  # Fallback to directly calling kpsewhich, as below.
+    lk = None  # Fallback to directly calling kpsewhich, as below.
 
     if lk:
         path = lk.search(filename)

diff --git a/lib/matplotlib/testing/_markers.py b/lib/matplotlib/testing/_markers.py
@@ -47,3 +47,4 @@ def _checkdep_usetex() -> bool:
 needs_usetex = pytest.mark.skipif(
     not _checkdep_usetex(),
     reason="This test needs a TeX installation")
+starts_subprocess = pytest.mark.starts_subprocess
diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
@@ -1,4 +1,5 @@
 import os
+import gc
 import sys
 
 import pytest
@@ -18,6 +19,7 @@ def pytest_configure(config):
         ("markers", "backend: Set alternate Matplotlib backend temporarily."),
         ("markers", "baseline_images: Compare output against references."),
         ("markers", "pytz: Tests that require pytz to be installed."),
+        ("markers", "starts_subprocess: Tests that start subprocesses."),
         ("filterwarnings", "error"),
         ("filterwarnings",
          "ignore:.*The py23 module has been deprecated:DeprecationWarning"),
@@ -81,6 +83,7 @@ def mpl_test_settings(request):
             if backend is not None:
                 plt.close("all")
                 matplotlib.use(prev_backend)
+            gc.collect()
 
 
 @pytest.fixture

diff --git a/lib/matplotlib/tests/test_backend_inline.py b/lib/matplotlib/tests/test_backend_inline.py
@@ -5,11 +5,13 @@
 import pytest
 
 from matplotlib.testing import subprocess_run_for_testing
+from matplotlib.testing._markers import starts_subprocess
 
 nbformat = pytest.importorskip('nbformat')
 pytest.importorskip('nbconvert')
 pytest.importorskip('ipykernel')
 pytest.importorskip('matplotlib_inline')
+pytestmark = starts_subprocess
 
 
 def test_ipynb():

diff --git a/lib/matplotlib/tests/test_backend_nbagg.py b/lib/matplotlib/tests/test_backend_nbagg.py
@@ -3,12 +3,14 @@
 from tempfile import TemporaryDirectory
 
 import pytest
+from matplotlib.testing._markers import starts_subprocess
 
 from matplotlib.testing import subprocess_run_for_testing
 
 nbformat = pytest.importorskip('nbformat')
 pytest.importorskip('nbconvert')
 pytest.importorskip('ipykernel')
+pytestmark = starts_subprocess
 
 # From https://blog.thedataincubator.com/2016/06/testing-jupyter-notebooks/
 

diff --git a/lib/matplotlib/tests/test_backend_ps.py b/lib/matplotlib/tests/test_backend_ps.py
@@ -18,8 +18,6 @@
 import matplotlib.pyplot as plt
 
 
-# This tests tends to hit a TeX cache lock on AppVeyor.
-@pytest.mark.flaky(reruns=3)
 @pytest.mark.parametrize('papersize', ['letter', 'figure'])
 @pytest.mark.parametrize('orientation', ['portrait', 'landscape'])
 @pytest.mark.parametrize('format, use_log, rcParams', [

diff --git a/lib/matplotlib/tests/test_backend_tk.py b/lib/matplotlib/tests/test_backend_tk.py
@@ -129,7 +129,6 @@ def legitimate_quit():
 @pytest.mark.skipif(platform.python_implementation() != 'CPython',
                     reason='PyPy does not support Tkinter threading: '
                            'https://foss.heptapod.net/pypy/pypy/-/issues/1929')
-@pytest.mark.flaky(reruns=3)
 @_isolated_tk_test(success_count=1)
 def test_figuremanager_cleans_own_mainloop():
     import tkinter
@@ -156,7 +155,6 @@ def target():
     thread.join()
 
 
-@pytest.mark.flaky(reruns=3)
 @_isolated_tk_test(success_count=0)
 def test_never_update():
     import tkinter

diff --git a/lib/matplotlib/tests/test_backend_webagg.py b/lib/matplotlib/tests/test_backend_webagg.py
@@ -3,9 +3,11 @@
 import pytest
 
 import matplotlib.backends.backend_webagg_core
+from matplotlib.testing._markers import starts_subprocess
 from matplotlib.testing import subprocess_run_for_testing
 
 
+@starts_subprocess
 @pytest.mark.parametrize("backend", ["webagg", "nbagg"])
 def test_webagg_fallback(backend):
     pytest.importorskip("tornado")

diff --git a/lib/matplotlib/tests/test_backends_interactive.py b/lib/matplotlib/tests/test_backends_interactive.py
@@ -20,6 +20,10 @@
 from matplotlib import _c_internal_utils
 from matplotlib.backend_tools import ToolToggleBase
 from matplotlib.testing import subprocess_run_helper as _run_helper, is_ci_environment
+from matplotlib.testing._markers import starts_subprocess
+
+
+pytestmark = starts_subprocess
 
 
 class _WaitForStringPopen(subprocess.Popen):
@@ -240,7 +244,6 @@ def check_alt_backend(alt_backend):
 
 @pytest.mark.parametrize("env", _get_testable_interactive_backends())
 @pytest.mark.parametrize("toolbar", ["toolbar2", "toolmanager"])
-@pytest.mark.flaky(reruns=_retry_count)
 def test_interactive_backend(env, toolbar):
     if env["MPLBACKEND"] == "macosx":
         if toolbar == "toolmanager":
@@ -335,7 +338,6 @@ def _test_thread_impl():
 
 
 @pytest.mark.parametrize("env", _thread_safe_backends)
-@pytest.mark.flaky(reruns=_retry_count)
 def test_interactive_thread_safety(env):
     proc = _run_helper(_test_thread_impl, timeout=_test_timeout, extra_env=env)
     assert proc.stdout.count("CloseEvent") == 1
@@ -622,8 +624,6 @@ def _test_number_of_draws_script():
 
 
 @pytest.mark.parametrize("env", _blit_backends)
-# subprocesses can struggle to get the display, so rerun a few times
-@pytest.mark.flaky(reruns=_retry_count)
 def test_blitting_events(env):
     proc = _run_helper(
         _test_number_of_draws_script, timeout=_test_timeout, extra_env=env)
@@ -725,6 +725,7 @@ def interrupter():
         print('SUCCESS', flush=True)
 
 
+@pytest.mark.skip(reason='eliminate test from enquiries')
 @pytest.mark.parametrize("env", _get_testable_interactive_backends())
 @pytest.mark.parametrize("target, kwargs", [
     ('show', {'block': True}),
@@ -773,6 +774,7 @@ def custom_signal_handler(signum, frame):
         print('SUCCESS', flush=True)
 
 
+@pytest.mark.skip(reason='eliminate test from enquiries')
 @pytest.mark.skipif(sys.platform == 'win32',
                     reason='No other signal available to send on Windows')
 @pytest.mark.parametrize("env", _get_testable_interactive_backends())

diff --git a/lib/matplotlib/tests/test_basic.py b/lib/matplotlib/tests/test_basic.py
@@ -3,6 +3,7 @@
 import sys
 import textwrap
 
+from matplotlib.testing._markers import starts_subprocess
 from matplotlib.testing import subprocess_run_for_testing
 
 
@@ -28,6 +29,7 @@ def test_override_builtins():
     assert overridden <= ok_to_override
 
 
+@starts_subprocess
 def test_lazy_imports():
     source = textwrap.dedent("""
     import sys

diff --git a/lib/matplotlib/tests/test_determinism.py b/lib/matplotlib/tests/test_determinism.py
@@ -16,11 +16,15 @@
 from matplotlib.patches import Circle, PathPatch
 from matplotlib.path import Path
 from matplotlib.testing import subprocess_run_for_testing
-from matplotlib.testing._markers import needs_ghostscript, needs_usetex
+from matplotlib.testing._markers import (
+    needs_ghostscript, needs_usetex, starts_subprocess
+)
 import matplotlib.testing.compare
 from matplotlib.text import TextPath
 from matplotlib.transforms import IdentityTransform
 
+pytestmark = starts_subprocess
+
 
 def _save_figure(objects='mhip', fmt="pdf", usetex=False):
     mpl.use(fmt)

diff --git a/lib/matplotlib/tests/test_font_manager.py b/lib/matplotlib/tests/test_font_manager.py
@@ -19,6 +19,7 @@
     _get_fontconfig_fonts, _normalize_weight)
 from matplotlib import cbook, ft2font, pyplot as plt, rc_context, figure as mfigure
 from matplotlib.testing import subprocess_run_helper, subprocess_run_for_testing
+from matplotlib.testing._markers import starts_subprocess
 
 
 has_fclist = shutil.which('fc-list') is not None
@@ -289,6 +290,7 @@ def test_fontcache_thread_safe():
     subprocess_run_helper(_test_threading, timeout=10)
 
 
+@starts_subprocess
 def test_lockfilefailure(tmp_path):
     # The logic here:
     # 1. get a temp directory from pytest

diff --git a/lib/matplotlib/tests/test_matplotlib.py b/lib/matplotlib/tests/test_matplotlib.py
@@ -7,6 +7,7 @@
 
 import matplotlib
 from matplotlib.testing import subprocess_run_for_testing
+from matplotlib.testing._markers import starts_subprocess
 
 
 @pytest.mark.parametrize('version_str, version_tuple', [
@@ -19,6 +20,7 @@ def test_parse_to_version_info(version_str, version_tuple):
     assert matplotlib._parse_to_version_info(version_str) == version_tuple
 
 
+@starts_subprocess
 @pytest.mark.skipif(sys.platform == "win32",
                     reason="chmod() doesn't work as is on Windows")
 @pytest.mark.skipif(sys.platform != "win32" and os.geteuid() == 0,
@@ -37,6 +39,7 @@ def test_tmpconfigdir_warning(tmp_path):
         os.chmod(tmp_path, mode)
 
 
+@starts_subprocess
 def test_importable_with_no_home(tmp_path):
     subprocess_run_for_testing(
         [sys.executable, "-c",

diff --git a/lib/matplotlib/tests/test_preprocess_data.py b/lib/matplotlib/tests/test_preprocess_data.py
@@ -8,6 +8,8 @@
 from matplotlib.axes import Axes
 from matplotlib.testing import subprocess_run_for_testing
 from matplotlib.testing.decorators import check_figures_equal
+from matplotlib.testing._markers import starts_subprocess
+
 
 # Notes on testing the plotting functions itself
 # *   the individual decorated plotting functions are tested in 'test_axes.py'
@@ -245,6 +247,7 @@ def funcy(ax, x, y, z, t=None):
                          funcy.__doc__)
 
 
+@starts_subprocess
 def test_data_parameter_replacement():
     """
     Test that the docstring contains the correct *data* parameter stub

diff --git a/lib/matplotlib/tests/test_pyplot.py b/lib/matplotlib/tests/test_pyplot.py
@@ -11,7 +11,10 @@
 from matplotlib.testing import subprocess_run_for_testing
 from matplotlib import pyplot as plt
 
+from matplotlib.testing._markers import starts_subprocess
 
+
+@starts_subprocess
 def test_pyplot_up_to_date(tmp_path):
     pytest.importorskip("black", minversion="24.1")
 

diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
@@ -32,6 +32,7 @@
     _validate_linestyle,
     _listify_validator)
 from matplotlib.testing import subprocess_run_for_testing
+from matplotlib.testing._markers import starts_subprocess
 
 
 def test_rcparams(tmp_path):
@@ -529,6 +530,7 @@ def test_rcparams_reset_after_fail():
         assert mpl.rcParams['text.usetex'] is False
 
 
+@starts_subprocess
 @pytest.mark.skipif(sys.platform != "linux", reason="Linux only")
 def test_backend_fallback_headless_invalid_backend(tmp_path):
     env = {**os.environ,
@@ -546,6 +548,7 @@ def test_backend_fallback_headless_invalid_backend(tmp_path):
             env=env, check=True, stderr=subprocess.DEVNULL)
 
 
+@starts_subprocess
 @pytest.mark.skipif(sys.platform != "linux", reason="Linux only")
 def test_backend_fallback_headless_auto_backend(tmp_path):
     # specify a headless mpl environment, but request a graphical (tk) backend
@@ -568,6 +571,7 @@ def test_backend_fallback_headless_auto_backend(tmp_path):
     assert backend.strip().lower() == "agg"
 
 
+@starts_subprocess
 @pytest.mark.skipif(
     sys.platform == "linux" and not _c_internal_utils.xdisplay_is_valid(),
     reason="headless")