Support without distutils (#2146)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: gaborbernat

.github/workflows/check.yml

@@ -24,6 +24,7 @@ jobs:
           - windows-latest
           - macos-latest
         py:
+          - 3.10.0-beta.4
           - 3.9
           - 3.8
           - 3.7

.pre-commit-config.yaml

@@ -42,7 +42,7 @@ repos:
   rev: v1.17.0
   hooks:
   - id: setup-cfg-fmt
-    args: [--min-py3-version, "3.4"]
+    args: [--min-py3-version, "3.5", "--max-py-version", "3.10"]
 - repo: https://github.com/PyCQA/flake8
   rev: "3.9.2"
   hooks:

docs/changelog/1910.feature.rst

@@ -0,0 +1,2 @@
+Support Python interpreters without ``distutils`` (fallback to ``syconfig`` in these cases) - by :user:`gaborbernat`.
+

setup.cfg

@@ -26,6 +26,7 @@ classifiers =
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: Implementation :: PyPy
     Topic :: Software Development :: Libraries

src/virtualenv/create/describe.py

@@ -30,15 +30,15 @@ def bin_dir(self):
 
     @property
     def script_dir(self):
-        return self.dest / Path(self.interpreter.distutils_install["scripts"])
+        return self.dest / self.interpreter.install_path("scripts")
 
     @property
     def purelib(self):
-        return self.dest / self.interpreter.distutils_install["purelib"]
+        return self.dest / self.interpreter.install_path("purelib")
 
     @property
     def platlib(self):
-        return self.dest / self.interpreter.distutils_install["platlib"]
+        return self.dest / self.interpreter.install_path("platlib")
 
     @property
     def libs(self):

src/virtualenv/create/via_global_ref/builtin/cpython/cpython2.py

@@ -36,7 +36,7 @@ def host_include_marker(cls, interpreter):
     @property
     def include(self):
         # the pattern include the distribution name too at the end, remove that via the parent call
-        return (self.dest / self.interpreter.distutils_install["headers"]).parent
+        return (self.dest / self.interpreter.install_path("headers")).parent
 
     @classmethod
     def modules(cls):

src/virtualenv/create/via_global_ref/builtin/pypy/pypy2.py

@@ -41,7 +41,7 @@ def host_include_marker(cls, interpreter):
 
     @property
     def include(self):
-        return self.dest / self.interpreter.distutils_install["headers"]
+        return self.dest / self.interpreter.install_path("headers")
 
     @classmethod
     def modules(cls):

src/virtualenv/discovery/py_info.py

@@ -12,9 +12,8 @@
 import re
 import sys
 import sysconfig
+import warnings
 from collections import OrderedDict, namedtuple
-from distutils import dist
-from distutils.command.install import SCHEME_KEYS
 from string import digits
 
 VersionInfo = namedtuple("VersionInfo", ["major", "minor", "micro", "releaselevel", "serial"])
@@ -118,10 +117,28 @@ def _fast_get_system_executable(self):
         # note we must choose the original and not the pure executable as shim scripts might throw us off
         return self.original_executable
 
+    def install_path(self, key):
+        result = self.distutils_install.get(key)
+        if result is None:  # use sysconfig if distutils is unavailable
+            # set prefixes to empty => result is relative from cwd
+            prefixes = self.prefix, self.exec_prefix, self.base_prefix, self.base_exec_prefix
+            config_var = {k: "" if v in prefixes else v for k, v in self.sysconfig_vars}
+            result = self.sysconfig_path(key, config_var=config_var).lstrip(os.sep)
+        return result
+
     @staticmethod
     def _distutils_install():
-        # follow https://github.com/pypa/pip/blob/main/src/pip/_internal/locations.py#L95
+        # use distutils primarily because that's what pip does
+        # https://github.com/pypa/pip/blob/main/src/pip/_internal/locations.py#L95
         # note here we don't import Distribution directly to allow setuptools to patch it
+        with warnings.catch_warnings():  # disable warning for PEP-632
+            warnings.simplefilter("ignore")
+            try:
+                from distutils import dist
+                from distutils.command.install import SCHEME_KEYS
+            except ImportError:  # if removed or not installed ignore
+                return {}
+
         d = dist.Distribution({"script_args": "--no-user-cfg"})  # conf files not parsed so they do not hijack paths
         if hasattr(sys, "_framework"):
             sys._framework = None  # disable macOS static paths for framework
@@ -177,7 +194,7 @@ def system_include(self):
         )
         if not os.path.exists(path):  # some broken packaging don't respect the sysconfig, fallback to distutils path
             # the pattern include the distribution name too at the end, remove that via the parent call
-            fallback = os.path.join(self.prefix, os.path.dirname(self.distutils_install["headers"]))
+            fallback = os.path.join(self.prefix, os.path.dirname(self.install_path("headers")))
             if os.path.exists(fallback):
                 path = fallback
         return path

tests/unit/activation/test_powershell.py

@@ -9,7 +9,9 @@
 
 
 @pytest.mark.slow
-def test_powershell(activation_tester_class, activation_tester):
+def test_powershell(activation_tester_class, activation_tester, monkeypatch):
+    monkeypatch.setenv("TERM", "xterm")
+
     class PowerShell(activation_tester_class):
         def __init__(self, session):
             cmd = "powershell.exe" if sys.platform == "win32" else "pwsh"

tests/unit/discovery/py_info/test_py_info_exe_based_of.py

@@ -17,7 +17,7 @@ def test_discover_empty_folder(tmp_path, monkeypatch, session_app_data):
         CURRENT.discover_exe(session_app_data, prefix=str(tmp_path))
 
 
-BASE = (CURRENT.distutils_install["scripts"], ".")
+BASE = (CURRENT.install_path("scripts"), ".")
 
 
 @pytest.mark.skipif(not fs_supports_symlink(), reason="symlink is not supported")

tests/unit/discovery/test_discovery.py

@@ -27,7 +27,7 @@ def test_discovery_via_path(monkeypatch, case, tmp_path, caplog, session_app_dat
     elif case == "upper":
         name = name.upper()
     exe_name = "{}{}{}".format(name, current.version_info.major, ".exe" if sys.platform == "win32" else "")
-    target = tmp_path / current.distutils_install["scripts"]
+    target = tmp_path / current.install_path("scripts")
     target.mkdir(parents=True)
     executable = target / exe_name
     os.symlink(sys.executable, ensure_text(str(executable)))