matplotlib · QuLogic · Jun 4, 2024 · Jun 5, 2024 · Jun 5, 2024 · Sep 26, 2024
diff --git a/.github/labeler.yml b/.github/labeler.yml
@@ -1,7 +1,9 @@
 ---
 "CI: Run cibuildwheel":
   - changed-files:
-      - any-glob-to-any-file: ['.github/workflows/cibuildwheel.yml']
+      - any-glob-to-any-file:
+          - '.github/workflows/cibuildwheel.yml'
+          - '.github/workflows/wasm.yml'
 "CI: Run cygwin":
   - changed-files:
       - any-glob-to-any-file: ['.github/workflows/cygwin.yml']

diff --git a/.github/workflows/wasm.yml b/.github/workflows/wasm.yml
@@ -0,0 +1,58 @@
+---
+name: Build wasm wheels
+
+on:
+  # Save CI by only running this on release branches or tags.
+  push:
+    branches:
+      - main
+      - v[0-9]+.[0-9]+.x
+    tags:
+      - v*
+  # Also allow running this action on PRs if requested by applying the
+  # "Run cibuildwheel" label.
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - labeled
+
+permissions:
+  contents: read
+
+jobs:
+  build_wasm:
+    if: >-
+      github.event_name == 'push' ||
+      github.event_name == 'pull_request' && (
+        (
+          github.event.action == 'labeled' &&
+          github.event.label.name == 'CI: Run cibuildwheel'
+        ) ||
+        contains(github.event.pull_request.labels.*.name,
+                 'CI: Run cibuildwheel')
+      )
+    name: Build wasm
+    runs-on: ubuntu-24.04
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-python@v5
+        name: Install Python
+        with:
+          python-version: '3.12'
+
+      - name: Build wheels for wasm
+        uses: pypa/cibuildwheel@7940a4c0e76eb2030e473a5f864f291f63ee879b  # v2.21.3
+        env:
+          CIBW_PLATFORM: "pyodide"
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: cibw-wheels-${{ runner.os }}-${{ matrix.cibw_archs }}
+          path: ./wheelhouse/*.whl
+          if-no-files-found: error
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -360,6 +360,8 @@ def bin_path(cls):
     @classmethod
     def isAvailable(cls):
         """Return whether a MovieWriter subclass is actually available."""
+        if sys.platform == 'emscripten':
+            return False
         return shutil.which(cls.bin_path()) is not None
 
 

diff --git a/lib/matplotlib/dviread.py b/lib/matplotlib/dviread.py
@@ -1070,7 +1070,7 @@ def find_tex_file(filename):
 
     try:
         lk = _LuatexKpsewhich()
-    except FileNotFoundError:
+    except (FileNotFoundError, OSError):
         lk = None  # Fallback to directly calling kpsewhich, as below.
 
     if lk:
@@ -1090,7 +1090,7 @@ def find_tex_file(filename):
             path = (cbook._check_and_log_subprocess(['kpsewhich', filename],
                                                     _log, **kwargs)
                     .rstrip('\n'))
-        except (FileNotFoundError, RuntimeError):
+        except (FileNotFoundError, OSError, RuntimeError):
             path = None
 
     if path:

diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -287,6 +287,9 @@
         if sys.platform == 'win32':
             installed_fonts = _get_win32_installed_fonts()
             fontpaths = []
+        elif sys.platform == 'emscripten':
+            installed_fonts = []
+            fontpaths = []
         else:
             installed_fonts = _get_fontconfig_fonts()
             if sys.platform == 'darwin':
@@ -1092,9 +1095,12 @@
         self.ttflist = []
 
         # Delay the warning by 5s.
-        timer = threading.Timer(5, lambda: _log.warning(
-            'Matplotlib is building the font cache; this may take a moment.'))
-        timer.start()
+        try:
+            timer = threading.Timer(5, lambda: _log.warning(
+                'Matplotlib is building the font cache; this may take a moment.'))
+            timer.start()
+        except RuntimeError:
+            timer = None
         try:
             for fontext in ["afm", "ttf"]:
                 for path in [*findSystemFonts(paths, fontext=fontext),
@@ -1107,7 +1113,8 @@
                         _log.info("Failed to extract font properties from %s: "
                                   "%s", path, exc)
         finally:
-            timer.cancel()
+            if timer:
+                timer.cancel()
 
     def addfont(self, path):
         """

diff --git a/lib/matplotlib/mlab.py b/lib/matplotlib/mlab.py
@@ -49,6 +49,7 @@
 
 import functools
 from numbers import Number
+import sys
 
 import numpy as np
 
@@ -210,6 +211,30 @@
     return y - (b*x + a)
 
 
+def _stride_windows(x, n, noverlap=0):
+    if noverlap >= n:
+        raise ValueError('noverlap must be less than n')
+    if n < 1:
+        raise ValueError('n cannot be less than 1')
+
+    x = np.asarray(x)
+
+    if n == 1 and noverlap == 0:
+        return x[np.newaxis]
+    if n > x.size:
+        raise ValueError('n cannot be greater than the length of x')
+
+    # np.lib.stride_tricks.as_strided easily leads to memory corruption for
+    # non integer shape and strides, i.e. noverlap or n. See #3845.
+    noverlap = int(noverlap)
+    n = int(n)
+
+    step = n - noverlap
+    shape = (n, (x.shape[-1]-noverlap)//step)
+    strides = (x.strides[0], step*x.strides[0])
+    return np.lib.stride_tricks.as_strided(x, shape=shape, strides=strides)
+
+
 def _spectral_helper(x, y=None, NFFT=None, Fs=None, detrend_func=None,
                      window=None, noverlap=None, pad_to=None,
                      sides=None, scale_by_freq=None, mode=None):
@@ -304,17 +329,23 @@
         raise ValueError(
             "The window length must match the data's first dimension")
 
-    result = np.lib.stride_tricks.sliding_window_view(
-        x, NFFT, axis=0)[::NFFT - noverlap].T
+    if sys.maxsize > 2**32:  # NumPy version on 32-bit OOMs.
+        result = np.lib.stride_tricks.sliding_window_view(
+            x, NFFT, axis=0)[::NFFT - noverlap].T
+    else:
+        result = _stride_windows(x, NFFT, noverlap=noverlap)
     result = detrend(result, detrend_func, axis=0)
     result = result * window.reshape((-1, 1))
     result = np.fft.fft(result, n=pad_to, axis=0)[:numFreqs, :]
     freqs = np.fft.fftfreq(pad_to, 1/Fs)[:numFreqs]
 
     if not same_data:
         # if same_data is False, mode must be 'psd'
-        resultY = np.lib.stride_tricks.sliding_window_view(
-            y, NFFT, axis=0)[::NFFT - noverlap].T
+        if sys.maxsize > 2**32:  # NumPy version on 32-bit OOMs.
+            resultY = np.lib.stride_tricks.sliding_window_view(
+                y, NFFT, axis=0)[::NFFT - noverlap].T
+        else:
+            resultY = _stride_windows(y, NFFT, noverlap=noverlap)
         resultY = detrend(resultY, detrend_func, axis=0)
         resultY = resultY * window.reshape((-1, 1))
         resultY = np.fft.fft(resultY, n=pad_to, axis=0)[:numFreqs, :]

diff --git a/lib/matplotlib/testing/__init__.py b/lib/matplotlib/testing/__init__.py
@@ -88,6 +88,9 @@
     pytest.xfail
         If platform is Cygwin and subprocess reports a fork() failure.
     """
+    if sys.platform == 'emscripten':
+        import pytest
+        pytest.skip('emscripten does not support subprocesses')
     if capture_output:
         stdout = stderr = subprocess.PIPE
     try:
@@ -175,7 +178,7 @@
     try:
         mpl.dviread.find_tex_file(f"{package}.sty")
         return True
-    except FileNotFoundError:
+    except (FileNotFoundError, OSError):
         return False
 
 

diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -138,6 +138,8 @@
             try:
                 if 'microsoft' in uname().release.lower():
                     raise OSError  # On WSL, symlink breaks silently
+                if sys.platform == 'emscripten':
+                    raise OSError
                 os.symlink(orig_expected_path, expected_fname)
             except OSError:  # On Windows, symlink *may* be unavailable.
                 shutil.copyfile(orig_expected_path, expected_fname)

diff --git a/lib/matplotlib/tests/test_agg.py b/lib/matplotlib/tests/test_agg.py
@@ -1,4 +1,5 @@
 import io
+import sys
 
 import numpy as np
 from numpy.testing import assert_array_almost_equal
@@ -279,6 +280,7 @@ def test_draw_path_collection_error_handling():
         fig.canvas.draw()
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten', reason='Too large for emscripten VM')
 def test_chunksize_fails():
     # NOTE: This test covers multiple independent test scenarios in a single
     #       function, because each scenario uses ~2GB of memory and we don't

diff --git a/lib/matplotlib/tests/test_animation.py b/lib/matplotlib/tests/test_animation.py
@@ -278,6 +278,8 @@
     anim.save('unused.null', writer=NullMovieWriter())
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten',
+                    reason='emscripten does not support subprocesses')
 def test_movie_writer_registry():
     assert len(animation.writers._registered) > 0
     mpl.rcParams['animation.ffmpeg_path'] = "not_available_ever_xxxx"
@@ -546,6 +548,8 @@
 def test_movie_writer_invalid_path(anim):
     if sys.platform == "win32":
         match_str = r"\[WinError 3] .*'\\\\foo\\\\bar\\\\aardvark'"
+    elif sys.platform == "emscripten":
+        match_str = r"\[Errno 44] .*'/foo"
     else:
         match_str = r"\[Errno 2] .*'/foo"
     with pytest.raises(FileNotFoundError, match=match_str):

diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
@@ -1,7 +1,6 @@
 import datetime
 import decimal
 import io
-import os
 from pathlib import Path
 
 import numpy as np
@@ -307,8 +306,8 @@ def test_text_urls_tex():
             assert annot.Rect[1] == decimal.Decimal('0.7') * 72
 
 
-def test_pdfpages_fspath():
-    with PdfPages(Path(os.devnull)) as pdf:
+def test_pdfpages_fspath(tmp_path):
+    with PdfPages(tmp_path / 'unused.pdf') as pdf:
         pdf.savefig(plt.figure())
 
 

diff --git a/lib/matplotlib/tests/test_dviread.py b/lib/matplotlib/tests/test_dviread.py
@@ -1,6 +1,7 @@
 import json
 from pathlib import Path
 import shutil
+import sys
 
 import matplotlib.dviread as dr
 import pytest
@@ -60,7 +61,7 @@ def test_PsfontsMap(monkeypatch):
         fontmap[b'%']
 
 
-@pytest.mark.skipif(shutil.which("kpsewhich") is None,
+@pytest.mark.skipif(sys.platform == "emscripten" or shutil.which("kpsewhich") is None,
                     reason="kpsewhich is not available")
 def test_dviread():
     dirpath = Path(__file__).parent / 'baseline_images/dviread'

diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -3,6 +3,7 @@
 import io
 import pickle
 import platform
+import sys
 from threading import Timer
 from types import SimpleNamespace
 import warnings
@@ -1605,6 +1606,8 @@ def test_add_axes_kwargs():
     plt.close()
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten',
+                    reason='emscripten does not support threads')
 def test_ginput(recwarn):  # recwarn undoes warn filters at exit.
     warnings.filterwarnings("ignore", "cannot show the figure")
     fig, ax = plt.subplots()
@@ -1627,6 +1630,8 @@ def multi_presses():
     np.testing.assert_allclose(fig.ginput(3), [(.3, .4), (.5, .6)])
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten',
+                    reason='emscripten does not support threads')
 def test_waitforbuttonpress(recwarn):  # recwarn undoes warn filters at exit.
     warnings.filterwarnings("ignore", "cannot show the figure")
     fig = plt.figure()

diff --git a/lib/matplotlib/tests/test_font_manager.py b/lib/matplotlib/tests/test_font_manager.py
@@ -20,7 +20,7 @@
 from matplotlib.testing import subprocess_run_helper, subprocess_run_for_testing
 
 
-has_fclist = shutil.which('fc-list') is not None
+has_fclist = sys.platform != 'emscripten' and shutil.which('fc-list') is not None
 
 
 def test_font_priority():
@@ -228,6 +228,8 @@ def _model_handler(_):
     plt.close()
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten',
+                    reason='emscripten does not support subprocesses')
 @pytest.mark.skipif(not hasattr(os, "register_at_fork"),
                     reason="Cannot register at_fork handlers")
 def test_fork():

diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -193,8 +193,8 @@ def test_imsave_rgba_origin(origin):
 
 
 @pytest.mark.parametrize("fmt", ["png", "pdf", "ps", "eps", "svg"])
-def test_imsave_fspath(fmt):
-    plt.imsave(Path(os.devnull), np.array([[0, 1]]), format=fmt)
+def test_imsave_fspath(fmt, tmp_path):
+    plt.imsave(tmp_path / f'unused.{fmt}', np.array([[0, 1]]), format=fmt)
 
 
 def test_imsave_color_alpha():
@@ -1507,6 +1507,7 @@ def test_rc_interpolation_stage():
             mpl.rcParams["image.interpolation_stage"] = val
 
 
+@pytest.mark.skipif(sys.platform == 'emscripten', reason='Figure too large for WASM')
 # We check for the warning with a draw() in the test, but we also need to
 # filter the warning as it is emitted by the figure test decorator
 @pytest.mark.filterwarnings(r'ignore:Data with more than .* '

diff --git a/lib/matplotlib/tests/test_matplotlib.py b/lib/matplotlib/tests/test_matplotlib.py
@@ -18,9 +18,9 @@ def test_parse_to_version_info(version_str, version_tuple):
     assert matplotlib._parse_to_version_info(version_str) == version_tuple
 
 
-@pytest.mark.skipif(sys.platform == "win32",
+@pytest.mark.skipif(sys.platform not in ["linux", "darwin"],
                     reason="chmod() doesn't work as is on Windows")
-@pytest.mark.skipif(sys.platform != "win32" and os.geteuid() == 0,
+@pytest.mark.skipif(sys.platform in ["linux", "darwin"] and os.geteuid() == 0,
                     reason="chmod() doesn't work as root")
 def test_tmpconfigdir_warning(tmp_path):
     """Test that a warning is emitted if a temporary configdir must be used."""

diff --git a/lib/matplotlib/tests/test_mlab.py b/lib/matplotlib/tests/test_mlab.py
@@ -1,3 +1,5 @@
+import sys
+
 from numpy.testing import (assert_allclose, assert_almost_equal,
                            assert_array_equal, assert_array_almost_equal_nulp)
 import numpy as np
@@ -873,6 +875,8 @@ def test_single_dataset_element(self):
         with pytest.raises(ValueError):
             mlab.GaussianKDE([42])
 
+    @pytest.mark.skipif(sys.platform == 'emscripten',
+                        reason="WASM doesn't support floating-point exceptions")
     def test_silverman_multidim_dataset(self):
         """Test silverman's for a multi-dimensional array."""
         x1 = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
@@ -886,6 +890,8 @@ def test_silverman_singledim_dataset(self):
         y_expected = 0.76770389927475502
         assert_almost_equal(mygauss.covariance_factor(), y_expected, 7)
 
+    @pytest.mark.skipif(sys.platform == 'emscripten',
+                        reason="WASM doesn't support floating-point exceptions")
     def test_scott_multidim_dataset(self):
         """Test scott's output for a multi-dimensional array."""
         x1 = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])