René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: test_invisible_Line_rendering test is flaky (too short timeout)","articleBody":"### Bug summary\n\nHi,\n\nRunning the test suite of 3.10.8 a couple times, eventually I got:\n```\n=================================== FAILURES ===================================\n________________________ test_invisible_Line_rendering _________________________\n[gw11] linux -- Python 3.11.11 /gnu/store/v76lvm9985mj5h3kwrkif7gnqv3q30ck-python-wrapper-3.11.11/bin/python\n\n    @pytest.mark.flaky(reruns=3)\n    def test_invisible_Line_rendering():\n        \"\"\"\n        GitHub issue #1256 identified a bug in Line.draw method\n    \n        Despite visibility attribute set to False, the draw method was not\n        returning early enough and some pre-rendering code was executed\n        though not necessary.\n    \n        Consequence was an excessive draw time for invisible Line instances\n        holding a large number of points (Npts\u003e 10**6)\n        \"\"\"\n        # Creates big x and y data:\n        N = 10**7\n        x = np.linspace(0, 1, N)\n        y = np.random.normal(size=N)\n    \n        # Create a plot figure:\n        fig = plt.figure()\n        ax = plt.subplot()\n    \n        # Create a \"big\" Line instance:\n        l = mlines.Line2D(x, y)\n        l.set_visible(False)\n        # but don't add it to the Axis instance `ax`\n    \n        # [here Interactive panning and zooming is pretty responsive]\n        # Time the canvas drawing:\n        t_no_line = min(timeit.repeat(fig.canvas.draw, number=1, repeat=3))\n        # (gives about 25 ms)\n    \n        # Add the big invisible Line:\n        ax.add_line(l)\n    \n        # [Now interactive panning and zooming is very slow]\n        # Time the canvas drawing:\n        t_invisible_line = min(timeit.repeat(fig.canvas.draw, number=1, repeat=3))\n        # gives about 290 ms for N = 10**7 pts\n    \n        slowdown_factor = t_invisible_line / t_no_line\n        slowdown_threshold = 2  # trying to avoid false positive failures\n\u003e       assert slowdown_factor \u003c slowdown_threshold\nE       assert 2.218287122977422 \u003c 2\n\n/gnu/store/j1595nb44lp30vbjd9c8iadzf8z7d3ry-python-matplotlib-3.10.8/lib/python3.11/site-packages/matplotlib/tests/test_lines.py:77: AssertionError\n------------------------------ Captured log setup ------------------------------\nWARNING  matplotlib.testing:__init__.py:38 Could not set locale to English/United States. Some date-related tests may fail.\n=========================== short test summary info ============================\nFAILED tests/test_lines.py::test_invisible_Line_rendering - assert 2.218287122977422 \u003c 2\n========== 1 failed, 6592 passed, 1521 skipped, 29 xfailed in 24.07s ===========\n\n```\n\n### Code for reproduction\n\n```Python\nI build on Guix with this package:\n\n(define-public python-matplotlib\n  (package\n    (name \"python-matplotlib\")\n    (version \"3.10.8\")\n    (source (origin\n              (method git-fetch)\n              (uri (git-reference\n                     (url \"https://github.com/matplotlib/matplotlib\")\n                     (commit (string-append \"v\" version))))\n              (file-name (git-file-name name version))\n              (sha256\n               (base32\n                \"1rlday52hcyrp7xfbdf4z8lzgnxkpfvjxnl9qmq0jvc3ph3n8k5i\"))))\n    (build-system pyproject-build-system)\n    (arguments\n     (list\n      #:configure-flags\n      ''((\"setup-args\" . #(\"-DrcParams-backend=TkAgg\"\n                           \"-Dsystem-freetype=true\"\n                           \"-Dsystem-qhull=true\"))\n         (\"install-args\" . \"--tags=data,python-runtime,runtime,tests\"))\n      #:test-flags\n      #~(list \"-m\" \"not network\"\n              \"-n\" (number-\u003estring (parallel-job-count))\n              ;; Run the installed tests, which is what we want since not\n              ;; everything gets built in the source directory.\n              \"--pyargs\" \"matplotlib\"\n              \"-k\"\n              (string-join\n               (list\n                ;; XXX: Disable all image comparison tests because we're using\n                ;; a newer version of FreeType than matplotlib expects.  This\n                ;; leads to minor differences throughout the tests.\n                \"not image_comparison\"\n                \"check_figures_equal\"\n                \"png\"                   ;disables many problematic image tests\n                \"test_figure_legend_outside\"\n                \"test_ft2font_get_kerning\"\n                \"test_normal_axes\"\n                \"test_get_tightbbox_polar\")\n               \" and not \"))\n      #:phases\n      #~(modify-phases %standard-phases\n          (add-before 'build 'pretend-version\n            ;; The version string is usually derived via setuptools-scm, but\n            ;; without the git metadata available, the version string is set to\n            ;; '0.0.0'.\n            (lambda _\n              (setenv \"SETUPTOOLS_SCM_PRETEND_VERSION\" #$version)))\n          (add-after 'unpack 'patch-commands\n            (lambda _\n              (substitute* \"lib/matplotlib/tests/test_animation.py\"\n                ((\"/bin/sh\") (which \"sh\")))))\n          (add-after 'unpack 'patch-dlopen\n            (lambda* (#:key inputs #:allow-other-keys)\n              (substitute* \"src/_c_internal_utils.cpp\"\n                ((\"libX11.so.6\")\n                 (search-input-file inputs \"lib/libX11.so.6\")))))\n          (add-before 'build 'configure-environment\n            (lambda* (#:key inputs #:allow-other-keys)\n              ;; Fix rounding errors when using the x87 FPU.\n              (when (string-prefix? \"i686\" #$(%current-system))\n                (setenv \"CFLAGS\" \"-ffloat-store\"))))\n          (add-before 'check 'chdir\n            (lambda _\n              ;; Step out of the source directory to avoid interference.\n              (chdir \"/tmp\"))))))\n    (propagated-inputs\n     (list python-contourpy\n           python-cycler\n           python-dateutil\n           python-fonttools-minimal\n           python-importlib-resources\n           python-kiwisolver\n           python-numpy\n           python-packaging\n           python-pillow\n           python-pyparsing\n           `(,python \"tk\")))\n    (inputs\n     (list cairo\n           freetype\n           glib\n           libpng\n           qhull\n           tcl\n           tk))\n    (native-inputs\n     (list meson-python\n           pkg-config\n           pybind11\n           python-pytest\n           python-pytest-timeout\n           python-pytest-xdist\n           python-setuptools\n           python-setuptools-scm\n           python-wheel))\n    (home-page \"https://matplotlib.org/\")\n    (synopsis \"2D plotting library for Python\")\n    (description\n     \"Matplotlib is a Python 2D plotting library which produces publication\nquality figures in a variety of hardcopy formats and interactive environments\nacross platforms.  Matplotlib can be used in Python scripts, the python and\nipython shell, web application servers, and six graphical user interface\ntoolkits.\")\n    (license license:psfl)))\n\nBut it should be reproducible anywhere.\n```\n\n### Actual outcome\n\nTest fails.\n\n### Expected outcome\n\nTest should pass.\n\n### Additional information\n\n_No response_\n\n### Operating system\n\nGuix System\n\n### Matplotlib Version\n\n3.10.8\n\n### Matplotlib Backend\n\n_No response_\n\n### Python version\n\n3.11.11\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\ngit checkout","author":{"url":"https://github.com/apteryks","@type":"Person","name":"apteryks"},"datePublished":"2025-12-04T12:37:04.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/30809/matplotlib/issues/30809"}