From b8aa5b2cbd99aa93e1e2360d4298ff8fb75e594d Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Mon, 13 Sep 2021 08:14:59 +0200
Subject: [PATCH] Remove most visible dependencies on distutils.

They are instead replaced by slightly roundabout ways to get hold of the
same objects (CompilerError, CCompiler).

Only distutils.sysconfig remains; we should investigate whether the
stdlib's sysconfig is a satisfactory replacement for it.
---
 setup.py    | 12 ++++++------
 setupext.py | 34 ++++++++++++++++++++++++++++------
 2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/setup.py b/setup.py
index 93a1b4bc912f..6fc76f0747cd 100644
--- a/setup.py
+++ b/setup.py
@@ -29,14 +29,11 @@
 import shutil
 import subprocess
 
-from setuptools import setup, find_packages, Extension
+from setuptools import setup, find_packages, Distribution, Extension
 import setuptools.command.build_ext
 import setuptools.command.build_py
 import setuptools.command.sdist
 
-from distutils.errors import CompileError
-from distutils.dist import Distribution
-
 import setupext
 from setupext import print_raw, print_status
 
@@ -61,7 +58,10 @@ def has_flag(self, flagname):
         f.write('int main (int argc, char **argv) { return 0; }')
         try:
             self.compile([f.name], extra_postargs=[flagname])
-        except CompileError:
+        except Exception as exc:
+            # https://github.com/pypa/setuptools/issues/2698
+            if type(exc).__name__ != "CompileError":
+                raise
             return False
     return True
 
@@ -263,7 +263,7 @@ def make_release_tree(self, base_dir, files):
             package_data.setdefault(key, [])
             package_data[key] = list(set(val + package_data[key]))
 
-setup(  # Finally, pass this all along to distutils to do the heavy lifting.
+setup(  # Finally, pass this all along to setuptools to do the heavy lifting.
     name="matplotlib",
     description="Python plotting package",
     author="John D. Hunter, Michael Droettboom",
diff --git a/setupext.py b/setupext.py
index 81c4fb56eb72..8f84269919f4 100644
--- a/setupext.py
+++ b/setupext.py
@@ -1,6 +1,5 @@
 import configparser
-from distutils import ccompiler, sysconfig
-from distutils.core import Extension
+from distutils import sysconfig
 import functools
 import hashlib
 from io import BytesIO
@@ -16,6 +15,8 @@
 import textwrap
 import urllib.request
 
+from setuptools import Distribution, Extension
+
 _log = logging.getLogger(__name__)
 
 
@@ -523,9 +524,27 @@ def add_libagg_flags_and_sources(ext):
         os.path.join("extern", "agg24-svn", "src", x) for x in agg_sources)
 
 
-# First compile checkdep_freetype2.c, which aborts the compilation either
-# with "foo.h: No such file or directory" if the header is not found, or an
-# appropriate error message if the header indicates a too-old version.
+def get_ccompiler():
+    """
+    Return a new CCompiler instance.
+
+    CCompiler used to be constructible via `distutils.ccompiler.new_compiler`,
+    but this API was removed as part of the distutils deprecation.  Instead,
+    we trick setuptools into instantiating it by creating a dummy Distribution
+    with a list of extension modules that claims to be truthy, but is actually
+    empty, and then running the Distribution's build_ext command.  (If using
+    a plain empty ext_modules, build_ext would early-return without doing
+    anything.)
+    """
+
+    class L(list):
+        def __bool__(self):
+            return True
+
+    build_ext = Distribution({"ext_modules": L()}).get_command_obj("build_ext")
+    build_ext.finalize_options()
+    build_ext.run()
+    return build_ext.compiler
 
 
 class FreeType(SetupPackage):
@@ -533,6 +552,9 @@ class FreeType(SetupPackage):
 
     @classmethod
     def add_flags(cls, ext):
+        # checkdep_freetype2.c immediately aborts the compilation either with
+        # "foo.h: No such file or directory" if the header is not found, or an
+        # appropriate error message if the header indicates a too-old version.
         ext.sources.insert(0, 'src/checkdep_freetype2.c')
         if options.get('system_freetype'):
             pkg_config_setup_extension(
@@ -636,7 +658,7 @@ def do_custom_build(self, env):
                 f.truncate()
                 f.write(vcxproj)
 
-            cc = ccompiler.new_compiler()
+            cc = get_ccompiler()
             cc.initialize()  # Get msbuild in the %PATH% of cc.spawn.
             cc.spawn(["msbuild", str(sln_path),
                       "/t:Clean;Build",