Always copy executable on Windows 3+ (#1977)

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

@@ -42,18 +42,19 @@ class CPythonPosix(CPython, PosixSupports):
 class CPythonWindows(CPython, WindowsSupports):
     @classmethod
     def _executables(cls, interpreter):
-        executables = cls._win_executables(Path(interpreter.system_executable), interpreter, RefWhen.ANY)
-        for src, targets, must, when in executables:
-            yield src, targets, must, when
-
-    @classmethod
-    def _win_executables(cls, host, interpreter, when):
-        must = RefMust.COPY if interpreter.version_info.major == 2 else RefMust.NA
+        # symlink of the python executables does not work reliably, copy always instead
+        # - https://bugs.python.org/issue42013
+        # - venv
+        host = cls.host_python(interpreter)
         for path in (host.parent / n for n in {"python.exe", host.name}):
-            yield host, [path.name], must, when
+            yield host, [path.name], RefMust.COPY, RefWhen.ANY
         # for more info on pythonw.exe see https://stackoverflow.com/a/30313091
         python_w = host.parent / "pythonw.exe"
-        yield python_w, [python_w.name], must, when
+        yield python_w, [python_w.name], RefMust.COPY, RefWhen.ANY
+
+    @classmethod
+    def host_python(cls, interpreter):
+        return Path(interpreter.system_executable)
 
 
 def is_mac_os_framework(interpreter):

src/virtualenv/create/via_global_ref/builtin/cpython/cpython3.py

@@ -1,13 +1,12 @@
 from __future__ import absolute_import, unicode_literals
 
 import abc
-from itertools import chain
 from textwrap import dedent
 
 from six import add_metaclass
 
 from virtualenv.create.describe import Python3Supports
-from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest, RefMust, RefWhen
+from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.create.via_global_ref.store import is_store_python
 from virtualenv.util.path import Path
 
@@ -56,29 +55,21 @@ class CPython3Windows(CPythonWindows, CPython3):
     def sources(cls, interpreter):
         for src in super(CPython3Windows, cls).sources(interpreter):
             yield src
-        if cls.venv_37p(interpreter):
-            for dll in (i for i in Path(interpreter.system_executable).parent.iterdir() if i.suffix == ".dll"):
-                yield PathRefToDest(dll, cls.to_bin, RefMust.SYMLINK, RefWhen.SYMLINK)
-        else:
+        if not cls.venv_37p(interpreter):
             for src in cls.include_dll_and_pyd(interpreter):
                 yield src
 
-    @classmethod
-    def _executables(cls, interpreter):
-        system_exe = Path(interpreter.system_executable)
-        if cls.venv_37p(interpreter):
-            # starting with CPython 3.7 Windows ships with a venvlauncher.exe that avoids the need for dll/pyd copies
-            launcher = Path(interpreter.system_stdlib) / "venv" / "scripts" / "nt" / "python.exe"
-            executables = cls._win_executables(launcher, interpreter, RefWhen.COPY)
-            executables = chain(executables, cls._win_executables(system_exe, interpreter, RefWhen.SYMLINK))
-        else:
-            executables = cls._win_executables(system_exe, interpreter, RefWhen.ANY)
-        for src, targets, must, when in executables:
-            yield src, targets, must, when
-
     @staticmethod
     def venv_37p(interpreter):
-        return interpreter.version_info.minor > 6
+        return interpreter.version_info.minor >= 7
+
+    @classmethod
+    def host_python(cls, interpreter):
+        if cls.venv_37p(interpreter):
+            # starting with CPython 3.7 Windows ships with a venvlauncher.exe that avoids the need for dll/pyd copies
+            # it also means the wrapper must be copied to avoid bugs such as https://bugs.python.org/issue42013
+            return Path(interpreter.system_stdlib) / "venv" / "scripts" / "nt" / "python.exe"
+        return super(CPython3Windows, cls).host_python(interpreter)
 
     @classmethod
     def include_dll_and_pyd(cls, interpreter):

src/virtualenv/create/via_global_ref/builtin/via_global_self_do.py

@@ -4,7 +4,7 @@ from abc import ABCMeta
 
 from six import add_metaclass
 
-from virtualenv.create.via_global_ref.builtin.ref import ExePathRefToDest, RefMust
+from virtualenv.create.via_global_ref.builtin.ref import ExePathRefToDest, RefMust, RefWhen
 from virtualenv.util.path import ensure_dir
 
 from ..api import ViaGlobalRefApi, ViaGlobalRefMeta
@@ -89,7 +89,12 @@ class ViaGlobalRefVirtualenvBuiltin(ViaGlobalRefApi, VirtualenvBuiltin):
         try:
             self.enable_system_site_package = False
             for src in self._sources:
-                src.run(self, self.symlinks)
+                if (
+                    src.when == RefWhen.ANY
+                    or (src.when == RefWhen.SYMLINK and self.symlinks is True)
+                    or (src.when == RefWhen.COPY and self.symlinks is False)
+                ):
+                    src.run(self, self.symlinks)
         finally:
             if true_system_site != self.enable_system_site_package:
                 self.enable_system_site_package = true_system_site