third_party/python/matplotlib/init.patch

commit 78913db0555d6b47449ca3cb7478c94663a1e553
Author: Philipp Schrader <philipp.schrader@gmail.com>
Date:   Thu Oct 27 20:57:23 2022 -0700

    Make matplotlib hermetic

diff --git a/site-packages/matplotlib/__init__.py b/site-packages/matplotlib/__init__.py
index ba9cd6c..083ef5b 100644
--- a/site-packages/matplotlib/__init__.py
+++ b/site-packages/matplotlib/__init__.py
@@ -104,6 +104,46 @@ import warnings
 import numpy
 from packaging.version import parse as parse_version
 
+
+from bazel_tools.tools.python.runfiles import runfiles
+
+def _hermeticity_fixup():
+    _runfiles = runfiles.Create()
+    runfiles_dir = _runfiles.EnvVars()["RUNFILES_DIR"]
+    if not runfiles_dir:
+        raise FileNotFoundError("Failed runfiles lookup.")
+
+    matplotlib_base = os.path.dirname(os.path.dirname(__file__))
+
+    # Hack to point matplotlib at its data.
+    os.environ["MATPLOTLIBDATA"] = os.path.join(matplotlib_base, "matplotlib", "mpl-data")
+    # Avoid reading /etc/matplotlib in all cases. Matplotlib is pretty happy to
+    # escape the sandbox by using absolute paths.
+    os.environ["MATPLOTLIBRC"] = os.path.join(os.environ["MATPLOTLIBDATA"], "matplotlibrc")
+    # There's a bug where the temp directory gets set if MATPLOTLIBRC isn't set.
+    # That causes the directory to not be created in time. We set the variable
+    # manually here to work around the bug.
+    os.environ["MPLCONFIGDIR"] = "/tmp/matplotlib-nobody"
+
+    gtk_runtime_base = os.path.join(runfiles_dir, "gtk_runtime")
+
+    # Tell fontconfig where to find matplotlib's sandboxed font files.
+    os.environ["FONTCONFIG_PATH"] = "etc/fonts"
+    os.environ["FONTCONFIG_FILE"] = "fonts.conf"
+    os.environ["FONTCONFIG_SYSROOT"] = gtk_runtime_base
+
+    ld_library_path = os.getenv("LD_LIBRARY_PATH") or ""
+    if ld_library_path:
+        ld_library_path = ":" + ld_library_path
+
+    os.environ["LD_LIBRARY_PATH"] = ":".join([
+        gtk_runtime_base + "/lib/x86_64-linux-gnu",
+        gtk_runtime_base + "/usr/lib/x86_64-linux-gnu",
+    ]) + ld_library_path
+
+_hermeticity_fixup()
+
+
 # cbook must import matplotlib only within function
 # definitions, so it is safe to import from it here.
 from . import _api, _version, cbook, docstring, rcsetup
@@ -524,7 +564,7 @@ def get_cachedir():
 @_logged_cached('matplotlib data path: %s')
 def get_data_path():
     """Return the path to Matplotlib data."""
-    return str(Path(__file__).with_name("mpl-data"))
+    return str(Path(os.environ["MATPLOTLIBDATA"]))
 
 
 def matplotlib_fname():