[Bug]: test_invisible_Line_rendering test is flaky (too short timeout) #30809
Description
Bug summary
Hi,
Running the test suite of 3.10.8 a couple times, eventually I got:
=================================== FAILURES ===================================
________________________ test_invisible_Line_rendering _________________________
[gw11] linux -- Python 3.11.11 /gnu/store/v76lvm9985mj5h3kwrkif7gnqv3q30ck-python-wrapper-3.11.11/bin/python
@pytest.mark.flaky(reruns=3)
def test_invisible_Line_rendering():
"""
GitHub issue #1256 identified a bug in Line.draw method
Despite visibility attribute set to False, the draw method was not
returning early enough and some pre-rendering code was executed
though not necessary.
Consequence was an excessive draw time for invisible Line instances
holding a large number of points (Npts> 10**6)
"""
# Creates big x and y data:
N = 10**7
x = np.linspace(0, 1, N)
y = np.random.normal(size=N)
# Create a plot figure:
fig = plt.figure()
ax = plt.subplot()
# Create a "big" Line instance:
l = mlines.Line2D(x, y)
l.set_visible(False)
# but don't add it to the Axis instance `ax`
# [here Interactive panning and zooming is pretty responsive]
# Time the canvas drawing:
t_no_line = min(timeit.repeat(fig.canvas.draw, number=1, repeat=3))
# (gives about 25 ms)
# Add the big invisible Line:
ax.add_line(l)
# [Now interactive panning and zooming is very slow]
# Time the canvas drawing:
t_invisible_line = min(timeit.repeat(fig.canvas.draw, number=1, repeat=3))
# gives about 290 ms for N = 10**7 pts
slowdown_factor = t_invisible_line / t_no_line
slowdown_threshold = 2 # trying to avoid false positive failures
> assert slowdown_factor < slowdown_threshold
E assert 2.218287122977422 < 2
/gnu/store/j1595nb44lp30vbjd9c8iadzf8z7d3ry-python-matplotlib-3.10.8/lib/python3.11/site-packages/matplotlib/tests/test_lines.py:77: AssertionError
------------------------------ Captured log setup ------------------------------
WARNING matplotlib.testing:__init__.py:38 Could not set locale to English/United States. Some date-related tests may fail.
=========================== short test summary info ============================
FAILED tests/test_lines.py::test_invisible_Line_rendering - assert 2.218287122977422 < 2
========== 1 failed, 6592 passed, 1521 skipped, 29 xfailed in 24.07s ===========
Code for reproduction
I build on Guix with this package:
(define-public python-matplotlib
(package
(name "python-matplotlib")
(version "3.10.8")
(source (origin
(method git-fetch)
(uri (git-reference
(url "https://github.com/matplotlib/matplotlib")
(commit (string-append "v" version))))
(file-name (git-file-name name version))
(sha256
(base32
"1rlday52hcyrp7xfbdf4z8lzgnxkpfvjxnl9qmq0jvc3ph3n8k5i"))))
(build-system pyproject-build-system)
(arguments
(list
#:configure-flags
''(("setup-args" . #("-DrcParams-backend=TkAgg"
"-Dsystem-freetype=true"
"-Dsystem-qhull=true"))
("install-args" . "--tags=data,python-runtime,runtime,tests"))
#:test-flags
#~(list "-m" "not network"
"-n" (number->string (parallel-job-count))
;; Run the installed tests, which is what we want since not
;; everything gets built in the source directory.
"--pyargs" "matplotlib"
"-k"
(string-join
(list
;; XXX: Disable all image comparison tests because we're using
;; a newer version of FreeType than matplotlib expects. This
;; leads to minor differences throughout the tests.
"not image_comparison"
"check_figures_equal"
"png" ;disables many problematic image tests
"test_figure_legend_outside"
"test_ft2font_get_kerning"
"test_normal_axes"
"test_get_tightbbox_polar")
" and not "))
#:phases
#~(modify-phases %standard-phases
(add-before 'build 'pretend-version
;; The version string is usually derived via setuptools-scm, but
;; without the git metadata available, the version string is set to
;; '0.0.0'.
(lambda _
(setenv "SETUPTOOLS_SCM_PRETEND_VERSION" #$version)))
(add-after 'unpack 'patch-commands
(lambda _
(substitute* "lib/matplotlib/tests/test_animation.py"
(("/bin/sh") (which "sh")))))
(add-after 'unpack 'patch-dlopen
(lambda* (#:key inputs #:allow-other-keys)
(substitute* "src/_c_internal_utils.cpp"
(("libX11.so.6")
(search-input-file inputs "lib/libX11.so.6")))))
(add-before 'build 'configure-environment
(lambda* (#:key inputs #:allow-other-keys)
;; Fix rounding errors when using the x87 FPU.
(when (string-prefix? "i686" #$(%current-system))
(setenv "CFLAGS" "-ffloat-store"))))
(add-before 'check 'chdir
(lambda _
;; Step out of the source directory to avoid interference.
(chdir "/tmp"))))))
(propagated-inputs
(list python-contourpy
python-cycler
python-dateutil
python-fonttools-minimal
python-importlib-resources
python-kiwisolver
python-numpy
python-packaging
python-pillow
python-pyparsing
`(,python "tk")))
(inputs
(list cairo
freetype
glib
libpng
qhull
tcl
tk))
(native-inputs
(list meson-python
pkg-config
pybind11
python-pytest
python-pytest-timeout
python-pytest-xdist
python-setuptools
python-setuptools-scm
python-wheel))
(home-page "https://matplotlib.org/")
(synopsis "2D plotting library for Python")
(description
"Matplotlib is a Python 2D plotting library which produces publication
quality figures in a variety of hardcopy formats and interactive environments
across platforms. Matplotlib can be used in Python scripts, the python and
ipython shell, web application servers, and six graphical user interface
toolkits.")
(license license:psfl)))
But it should be reproducible anywhere.Actual outcome
Test fails.
Expected outcome
Test should pass.
Additional information
No response
Operating system
Guix System
Matplotlib Version
3.10.8
Matplotlib Backend
No response
Python version
3.11.11
Jupyter version
No response
Installation
git checkout