Copy venv/__init__.py into library

Add tests

library/venv/__init__.py

···
+#!/usr/bin/env python3
+# WARNING: This is mostly a copy of code from the cpython library.
+# flake8: noqa
+# fmt: off
+# isort:skip_file
+"""
+Virtual environment (venv) package for Python. Based on PEP 405.
+
+Copyright (C) 2011-2014 Vinay Sajip.
+Licensed to the PSF under a contributor agreement.
+"""
+import logging
+import os
+import shutil
+import subprocess
+import sys
+import sysconfig
+import types
+
+logger = logging.getLogger(__name__)
+
+
+class EnvBuilder:
+    """
+    This class exists to allow virtual environment creation to be
+    customized. The constructor parameters determine the builder's
+    behaviour when called upon to create a virtual environment.
+
+    By default, the builder makes the system (global) site-packages dir
+    *un*available to the created environment.
+
+    If invoked using the Python -m option, the default is to use copying
+    on Windows platforms but symlinks elsewhere. If instantiated some
+    other way, the default is to *not* use symlinks.
+
+    :param system_site_packages: If True, the system (global) site-packages
+                                 dir is available to created environments.
+    :param clear: If True, delete the contents of the environment directory if
+                  it already exists, before environment creation.
+    :param symlinks: If True, attempt to symlink rather than copy files into
+                     virtual environment.
+    :param upgrade: If True, upgrade an existing virtual environment.
+    :param with_pip: If True, ensure pip is installed in the virtual
+                     environment
+    :param prompt: Alternative terminal prefix for the environment.
+    """
+
+    def __init__(self, system_site_packages=False, clear=False,
+                 symlinks=False, upgrade=False, with_pip=False, prompt=None):
+        self.system_site_packages = system_site_packages
+        self.clear = clear
+        self.symlinks = symlinks
+        self.upgrade = upgrade
+        self.with_pip = with_pip
+        self.prompt = prompt
+
+    def create(self, env_dir):
+        """
+        Create a virtual environment in a directory.
+
+        :param env_dir: The target directory to create an environment in.
+
+        """
+        env_dir = os.path.abspath(env_dir)
+        context = self.ensure_directories(env_dir)
+        # See issue 24875. We need system_site_packages to be False
+        # until after pip is installed.
+        true_system_site_packages = self.system_site_packages
+        self.system_site_packages = False
+        self.create_configuration(context)
+        self.setup_python(context)
+        if self.with_pip:
+            self._setup_pip(context)
+        if not self.upgrade:
+            self.setup_scripts(context)
+            self.post_setup(context)
+        if true_system_site_packages:
+            # We had set it to False before, now
+            # restore it and rewrite the configuration
+            self.system_site_packages = True
+            self.create_configuration(context)
+
+    def clear_directory(self, path):
+        for fn in os.listdir(path):
+            fn = os.path.join(path, fn)
+            if os.path.islink(fn) or os.path.isfile(fn):
+                os.remove(fn)
+            elif os.path.isdir(fn):
+                shutil.rmtree(fn)
+
+    def ensure_directories(self, env_dir):
+        """
+        Create the directories for the environment.
+
+        Returns a context object which holds paths in the environment,
+        for use by subsequent logic.
+        """
+
+        def create_if_needed(d):
+            if not os.path.exists(d):
+                os.makedirs(d)
+            elif os.path.islink(d) or os.path.isfile(d):
+                raise ValueError('Unable to create directory %r' % d)
+
+        if os.path.exists(env_dir) and self.clear:
+            self.clear_directory(env_dir)
+        context = types.SimpleNamespace()
+        context.env_dir = env_dir
+        context.env_name = os.path.split(env_dir)[1]
+        prompt = self.prompt if self.prompt is not None else context.env_name
+        context.prompt = '(%s) ' % prompt
+        create_if_needed(env_dir)
+        executable = sys._base_executable
+        dirname, exename = os.path.split(os.path.abspath(executable))
+        context.executable = executable
+        context.python_dir = dirname
+        context.python_exe = exename
+        if sys.platform == 'win32':
+            binname = 'Scripts'
+            incpath = 'Include'
+            libpath = os.path.join(env_dir, 'Lib', 'site-packages')
+        else:
+            binname = 'bin'
+            incpath = 'include'
+            libpath = os.path.join(env_dir, 'lib',
+                                   'python%d.%d' % sys.version_info[:2],
+                                   'site-packages')
+        context.inc_path = path = os.path.join(env_dir, incpath)
+        create_if_needed(path)
+        create_if_needed(libpath)
+        # Issue 21197: create lib64 as a symlink to lib on 64-bit non-OS X POSIX
+        if ((sys.maxsize > 2**32) and (os.name == 'posix') and
+            (sys.platform != 'darwin')):
+            link_path = os.path.join(env_dir, 'lib64')
+            if not os.path.exists(link_path):   # Issue #21643
+                os.symlink('lib', link_path)
+        context.bin_path = binpath = os.path.join(env_dir, binname)
+        context.bin_name = binname
+        context.env_exe = os.path.join(binpath, exename)
+        create_if_needed(binpath)
+        return context
+
+    def create_configuration(self, context):
+        """
+        Create a configuration file indicating where the environment's Python
+        was copied from, and whether the system site-packages should be made
+        available in the environment.
+
+        :param context: The information for the environment creation request
+                        being processed.
+        """
+        context.cfg_path = path = os.path.join(context.env_dir, 'pyvenv.cfg')
+        with open(path, 'w', encoding='utf-8') as f:
+            f.write('home = %s\n' % context.python_dir)
+            if self.system_site_packages:
+                incl = 'true'
+            else:
+                incl = 'false'
+            f.write('include-system-site-packages = %s\n' % incl)
+            f.write('version = %d.%d.%d\n' % sys.version_info[:3])
+            if self.prompt is not None:
+                f.write(f'prompt = {self.prompt!r}\n')
+
+    if os.name != 'nt':
+        def symlink_or_copy(self, src, dst, relative_symlinks_ok=False):
+            """
+            Try symlinking a file, and if that fails, fall back to copying.
+            """
+            force_copy = not self.symlinks
+            if not force_copy:
+                try:
+                    if not os.path.islink(dst): # can't link to itself!
+                        if relative_symlinks_ok:
+                            assert os.path.dirname(src) == os.path.dirname(dst)
+                            os.symlink(os.path.basename(src), dst)
+                        else:
+                            os.symlink(src, dst)
+                except Exception:   # may need to use a more specific exception
+                    logger.warning('Unable to symlink %r to %r', src, dst)
+                    force_copy = True
+            if force_copy:
+                shutil.copyfile(src, dst)
+    else:
+        def symlink_or_copy(self, src, dst, relative_symlinks_ok=False):
+            """
+            Try symlinking a file, and if that fails, fall back to copying.
+            """
+            bad_src = os.path.lexists(src) and not os.path.exists(src)
+            if self.symlinks and not bad_src and not os.path.islink(dst):
+                try:
+                    if relative_symlinks_ok:
+                        assert os.path.dirname(src) == os.path.dirname(dst)
+                        os.symlink(os.path.basename(src), dst)
+                    else:
+                        os.symlink(src, dst)
+                    return
+                except Exception:   # may need to use a more specific exception
+                    logger.warning('Unable to symlink %r to %r', src, dst)
+
+            # On Windows, we rewrite symlinks to our base python.exe into
+            # copies of venvlauncher.exe
+            basename, ext = os.path.splitext(os.path.basename(src))
+            srcfn = os.path.join(os.path.dirname(__file__),
+                                 "scripts",
+                                 "nt",
+                                 basename + ext)
+            # Builds or venv's from builds need to remap source file
+            # locations, as we do not put them into Lib/venv/scripts
+            if sysconfig.is_python_build(True) or not os.path.isfile(srcfn):
+                if basename.endswith('_d'):
+                    ext = '_d' + ext
+                    basename = basename[:-2]
+                if basename == 'python':
+                    basename = 'venvlauncher'
+                elif basename == 'pythonw':
+                    basename = 'venvwlauncher'
+                src = os.path.join(os.path.dirname(src), basename + ext)
+            else:
+                src = srcfn
+            if not os.path.exists(src):
+                if not bad_src:
+                    logger.warning('Unable to copy %r', src)
+                return
+
+            shutil.copyfile(src, dst)
+
+    def setup_python(self, context):
+        """
+        Set up a Python executable in the environment.
+
+        :param context: The information for the environment creation request
+                        being processed.
+        """
+        binpath = context.bin_path
+        path = context.env_exe
+        copier = self.symlink_or_copy
+        dirname = context.python_dir
+        if os.name != 'nt':
+            copier(context.executable, path)
+            if not os.path.islink(path):
+                os.chmod(path, 0o755)
+            for suffix in ('python', 'python3'):
+                path = os.path.join(binpath, suffix)
+                if not os.path.exists(path):
+                    # Issue 18807: make copies if
+                    # symlinks are not wanted
+                    copier(context.env_exe, path, relative_symlinks_ok=True)
+                    if not os.path.islink(path):
+                        os.chmod(path, 0o755)
+        else:
+            if self.symlinks:
+                # For symlinking, we need a complete copy of the root directory
+                # If symlinks fail, you'll get unnecessary copies of files, but
+                # we assume that if you've opted into symlinks on Windows then
+                # you know what you're doing.
+                suffixes = [
+                    f for f in os.listdir(dirname) if
+                    os.path.normcase(os.path.splitext(f)[1]) in ('.exe', '.dll')
+                ]
+                if sysconfig.is_python_build(True):
+                    suffixes = [
+                        f for f in suffixes if
+                        os.path.normcase(f).startswith(('python', 'vcruntime'))
+                    ]
+            else:
+                suffixes = ['python.exe', 'python_d.exe', 'pythonw.exe',
+                            'pythonw_d.exe']
+
+            for suffix in suffixes:
+                src = os.path.join(dirname, suffix)
+                if os.path.lexists(src):
+                    copier(src, os.path.join(binpath, suffix))
+
+            if sysconfig.is_python_build(True):
+                # copy init.tcl
+                for root, dirs, files in os.walk(context.python_dir):
+                    if 'init.tcl' in files:
+                        tcldir = os.path.basename(root)
+                        tcldir = os.path.join(context.env_dir, 'Lib', tcldir)
+                        if not os.path.exists(tcldir):
+                            os.makedirs(tcldir)
+                        src = os.path.join(root, 'init.tcl')
+                        dst = os.path.join(tcldir, 'init.tcl')
+                        shutil.copyfile(src, dst)
+                        break
+
+    def _setup_pip(self, context):
+        """Installs or upgrades pip in a virtual environment"""
+        # We run ensurepip in isolated mode to avoid side effects from
+        # environment vars, the current directory and anything else
+        # intended for the global Python environment
+        cmd = [context.env_exe, '-Im', 'ensurepip', '--upgrade',
+                                                    '--default-pip']
+        subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+
+    def setup_scripts(self, context):
+        """
+        Set up scripts into the created environment from a directory.
+
+        This method installs the default scripts into the environment
+        being created. You can prevent the default installation by overriding
+        this method if you really need to, or if you need to specify
+        a different location for the scripts to install. By default, the
+        'scripts' directory in the venv package is used as the source of
+        scripts to install.
+        """
+        path = os.path.abspath(os.path.dirname(__file__))
+        path = os.path.join(path, 'scripts')
+        self.install_scripts(context, path)
+
+    def post_setup(self, context):
+        """
+        Hook for post-setup modification of the venv. Subclasses may install
+        additional packages or scripts here, add activation shell scripts, etc.
+
+        :param context: The information for the environment creation request
+                        being processed.
+        """
+        pass
+
+    def replace_variables(self, text, context):
+        """
+        Replace variable placeholders in script text with context-specific
+        variables.
+
+        Return the text passed in , but with variables replaced.
+
+        :param text: The text in which to replace placeholder variables.
+        :param context: The information for the environment creation request
+                        being processed.
+        """
+        text = text.replace('__VENV_DIR__', context.env_dir)
+        text = text.replace('__VENV_NAME__', context.env_name)
+        text = text.replace('__VENV_PROMPT__', context.prompt)
+        text = text.replace('__VENV_BIN_NAME__', context.bin_name)
+        text = text.replace('__VENV_PYTHON__', context.env_exe)
+        return text
+
+    def install_scripts(self, context, path):
+        """
+        Install scripts into the created environment from a directory.
+
+        :param context: The information for the environment creation request
+                        being processed.
+        :param path:    Absolute pathname of a directory containing script.
+                        Scripts in the 'common' subdirectory of this directory,
+                        and those in the directory named for the platform
+                        being run on, are installed in the created environment.
+                        Placeholder variables are replaced with environment-
+                        specific values.
+        """
+        binpath = context.bin_path
+        plen = len(path)
+        for root, dirs, files in os.walk(path):
+            if root == path: # at top-level, remove irrelevant dirs
+                for d in dirs[:]:
+                    if d not in ('common', os.name):
+                        dirs.remove(d)
+                continue # ignore files in top level
+            for f in files:
+                if (os.name == 'nt' and f.startswith('python')
+                        and f.endswith(('.exe', '.pdb'))):
+                    continue
+                srcfile = os.path.join(root, f)
+                suffix = root[plen:].split(os.sep)[2:]
+                if not suffix:
+                    dstdir = binpath
+                else:
+                    dstdir = os.path.join(binpath, *suffix)
+                if not os.path.exists(dstdir):
+                    os.makedirs(dstdir)
+                dstfile = os.path.join(dstdir, f)
+                with open(srcfile, 'rb') as f:
+                    data = f.read()
+                if not srcfile.endswith(('.exe', '.pdb')):
+                    try:
+                        data = data.decode('utf-8')
+                        data = self.replace_variables(data, context)
+                        data = data.encode('utf-8')
+                    except UnicodeError as e:
+                        data = None
+                        logger.warning('unable to copy script %r, '
+                                       'may be binary: %s', srcfile, e)
+                if data is not None:
+                    with open(dstfile, 'wb') as f:
+                        f.write(data)
+                    shutil.copymode(srcfile, dstfile)
+
+
+def create(env_dir, system_site_packages=False, clear=False,
+                    symlinks=False, with_pip=False, prompt=None):
+    """Create a virtual environment in a directory."""
+    builder = EnvBuilder(system_site_packages=system_site_packages,
+                         clear=clear, symlinks=symlinks, with_pip=with_pip,
+                         prompt=prompt)
+    builder.create(env_dir)
+
+def main(args=None):
+    compatible = True
+    if sys.version_info < (3, 3):
+        compatible = False
+    elif not hasattr(sys, 'base_prefix'):
+        compatible = False
+    if not compatible:
+        raise ValueError('This script is only for use with Python >= 3.3')
+    else:
+        import argparse
+
+        parser = argparse.ArgumentParser(prog=__name__,
+                                         description='Creates virtual Python '
+                                                     'environments in one or '
+                                                     'more target '
+                                                     'directories.',
+                                         epilog='Once an environment has been '
+                                                'created, you may wish to '
+                                                'activate it, e.g. by '
+                                                'sourcing an activate script '
+                                                'in its bin directory.')
+        parser.add_argument('dirs', metavar='ENV_DIR', nargs='+',
+                            help='A directory to create the environment in.')
+        parser.add_argument('--system-site-packages', default=False,
+                            action='store_true', dest='system_site',
+                            help='Give the virtual environment access to the '
+                                 'system site-packages dir.')
+        if os.name == 'nt':
+            use_symlinks = False
+        else:
+            use_symlinks = True
+        group = parser.add_mutually_exclusive_group()
+        group.add_argument('--symlinks', default=use_symlinks,
+                           action='store_true', dest='symlinks',
+                           help='Try to use symlinks rather than copies, '
+                                'when symlinks are not the default for '
+                                'the platform.')
+        group.add_argument('--copies', default=not use_symlinks,
+                           action='store_false', dest='symlinks',
+                           help='Try to use copies rather than symlinks, '
+                                'even when symlinks are the default for '
+                                'the platform.')
+        parser.add_argument('--clear', default=False, action='store_true',
+                            dest='clear', help='Delete the contents of the '
+                                               'environment directory if it '
+                                               'already exists, before '
+                                               'environment creation.')
+        parser.add_argument('--upgrade', default=False, action='store_true',
+                            dest='upgrade', help='Upgrade the environment '
+                                               'directory to use this version '
+                                               'of Python, assuming Python '
+                                               'has been upgraded in-place.')
+        parser.add_argument('--without-pip', dest='with_pip',
+                            default=True, action='store_false',
+                            help='Skips installing or upgrading pip in the '
+                                 'virtual environment (pip is bootstrapped '
+                                 'by default)')
+        parser.add_argument('--prompt',
+                            help='Provides an alternative prompt prefix for '
+                                 'this environment.')
+        options = parser.parse_args(args)
+        if options.upgrade and options.clear:
+            raise ValueError('you cannot supply --upgrade and --clear together.')
+        builder = EnvBuilder(system_site_packages=options.system_site,
+                             clear=options.clear,
+                             symlinks=options.symlinks,
+                             upgrade=options.upgrade,
+                             with_pip=options.with_pip,
+                             prompt=options.prompt)
+        for d in options.dirs:
+            builder.create(d)
+
+if __name__ == '__main__':
+    rc = 1
+    try:
+        main()
+        rc = 0
+    except Exception as e:
+        print('Error: %s' % e, file=sys.stderr)
+    sys.exit(rc)

library/venv_test.py

···
+#!/usr/bin/env python3
+import unittest
+
+
+class VenvTest(unittest.TestCase):
+    def test_it_imports(self):
+        import venv
+
+        self.assertEqual(venv.__name__, "venv")
+
+
+if __name__ == "__main__":
+    unittest.main()