Get matplotlib working with upstream Python
This patch adds support for using matplotlib plus its Gtk backend with
`--config=k8_upstream_python`. Unfortunately, the Tk backend doesn't
work because of how Python is packaged. See the following issue for
more information:
https://github.com/matplotlib/matplotlib/issues/23074
Separately, we need to patch pygobject and matplotlib for various
hermeticity reasons. To accomplish this, I've added patching support
for wheels downloaded via rules_python. I should have set it up to use
annotations (the same mechanism we use for injecting deps), but it was
a little cumbersome. Annotations are not set up for using in arguments
to repository rules. I instead opted for a separate JSON file. You can
find it at `tools/python/patches.json`.
You can try the two new example programs:
$ bazel run --config=k8_upstream_python //build_tests:matplotlib_example
$ bazel run --config=k8_upstream_python //build_tests:pygobject_example
Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
Change-Id: I3c4e8648a8012aa23dedd53610e82d590d1c409d
diff --git a/third_party/python/matplotlib/init.patch b/third_party/python/matplotlib/init.patch
new file mode 100644
index 0000000..8911145
--- /dev/null
+++ b/third_party/python/matplotlib/init.patch
@@ -0,0 +1,66 @@
+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"] = os.path.join(gtk_runtime_base, "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():