diff env/lib/python3.9/site-packages/virtualenv/create/via_global_ref/_virtualenv.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/virtualenv/create/via_global_ref/_virtualenv.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,130 @@
+"""Patches that are applied at runtime to the virtual environment"""
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+
+VIRTUALENV_PATCH_FILE = os.path.join(__file__)
+
+
+def patch_dist(dist):
+    """
+    Distutils allows user to configure some arguments via a configuration file:
+    https://docs.python.org/3/install/index.html#distutils-configuration-files
+
+    Some of this arguments though don't make sense in context of the virtual environment files, let's fix them up.
+    """
+    # we cannot allow some install config as that would get packages installed outside of the virtual environment
+    old_parse_config_files = dist.Distribution.parse_config_files
+
+    def parse_config_files(self, *args, **kwargs):
+        result = old_parse_config_files(self, *args, **kwargs)
+        install = self.get_option_dict("install")
+
+        if "prefix" in install:  # the prefix governs where to install the libraries
+            install["prefix"] = VIRTUALENV_PATCH_FILE, os.path.abspath(sys.prefix)
+        for base in ("purelib", "platlib", "headers", "scripts", "data"):
+            key = "install_{}".format(base)
+            if key in install:  # do not allow global configs to hijack venv paths
+                install.pop(key, None)
+        return result
+
+    dist.Distribution.parse_config_files = parse_config_files
+
+
+# Import hook that patches some modules to ignore configuration values that break package installation in case
+# of virtual environments.
+_DISTUTILS_PATCH = "distutils.dist", "setuptools.dist"
+if sys.version_info > (3, 4):
+    # https://docs.python.org/3/library/importlib.html#setting-up-an-importer
+    from functools import partial
+    from importlib.abc import MetaPathFinder
+    from importlib.util import find_spec
+
+    class _Finder(MetaPathFinder):
+        """A meta path finder that allows patching the imported distutils modules"""
+
+        fullname = None
+
+        # lock[0] is threading.Lock(), but initialized lazily to avoid importing threading very early at startup,
+        # because there are gevent-based applications that need to be first to import threading by themselves.
+        # See https://github.com/pypa/virtualenv/issues/1895 for details.
+        lock = []
+
+        def find_spec(self, fullname, path, target=None):
+            if fullname in _DISTUTILS_PATCH and self.fullname is None:
+                # initialize lock[0] lazily
+                if len(self.lock) == 0:
+                    import threading
+
+                    lock = threading.Lock()
+                    # there is possibility that two threads T1 and T2 are simultaneously running into find_spec,
+                    # observing .lock as empty, and further going into hereby initialization. However due to the GIL,
+                    # list.append() operation is atomic and this way only one of the threads will "win" to put the lock
+                    # - that every thread will use - into .lock[0].
+                    # https://docs.python.org/3/faq/library.html#what-kinds-of-global-value-mutation-are-thread-safe
+                    self.lock.append(lock)
+
+                with self.lock[0]:
+                    self.fullname = fullname
+                    try:
+                        spec = find_spec(fullname, path)
+                        if spec is not None:
+                            # https://www.python.org/dev/peps/pep-0451/#how-loading-will-work
+                            is_new_api = hasattr(spec.loader, "exec_module")
+                            func_name = "exec_module" if is_new_api else "load_module"
+                            old = getattr(spec.loader, func_name)
+                            func = self.exec_module if is_new_api else self.load_module
+                            if old is not func:
+                                try:
+                                    setattr(spec.loader, func_name, partial(func, old))
+                                except AttributeError:
+                                    pass  # C-Extension loaders are r/o such as zipimporter with <python 3.7
+                            return spec
+                    finally:
+                        self.fullname = None
+
+        @staticmethod
+        def exec_module(old, module):
+            old(module)
+            if module.__name__ in _DISTUTILS_PATCH:
+                patch_dist(module)
+
+        @staticmethod
+        def load_module(old, name):
+            module = old(name)
+            if module.__name__ in _DISTUTILS_PATCH:
+                patch_dist(module)
+            return module
+
+    sys.meta_path.insert(0, _Finder())
+else:
+    # https://www.python.org/dev/peps/pep-0302/
+    from imp import find_module
+    from pkgutil import ImpImporter, ImpLoader
+
+    class _VirtualenvImporter(object, ImpImporter):
+        def __init__(self, path=None):
+            object.__init__(self)
+            ImpImporter.__init__(self, path)
+
+        def find_module(self, fullname, path=None):
+            if fullname in _DISTUTILS_PATCH:
+                try:
+                    return _VirtualenvLoader(fullname, *find_module(fullname.split(".")[-1], path))
+                except ImportError:
+                    pass
+            return None
+
+    class _VirtualenvLoader(object, ImpLoader):
+        def __init__(self, fullname, file, filename, etc):
+            object.__init__(self)
+            ImpLoader.__init__(self, fullname, file, filename, etc)
+
+        def load_module(self, fullname):
+            module = super(_VirtualenvLoader, self).load_module(fullname)
+            patch_dist(module)
+            module.__loader__ = None  # distlib fallback
+            return module
+
+    sys.meta_path.append(_VirtualenvImporter())