copy ephemeral_environment function from 6400f42

poetry/utils/env.py

@@ -42,6 +42,7 @@
 from poetry.utils._compat import subprocess
 from poetry.utils.helpers import is_dir_writable
 from poetry.utils.helpers import paths_csv
+from poetry.utils.helpers import temporary_directory
 
 
 GET_ENVIRONMENT_INFO = """\
@@ -1598,6 +1599,21 @@ def _bin(self, bin):
         return bin
 
 
+@contextmanager
+def ephemeral_environment(executable=None, pip=False, wheel=None, setuptools=None):
+    with temporary_directory() as tmp_dir:
+        # TODO: cache PEP 517 build environment corresponding to each project venv
+        venv_dir = Path(tmp_dir) / ".venv"
+        EnvManager.build_venv(
+            path=venv_dir.as_posix(),
+            executable=executable,
+            with_pip=pip,
+            with_wheel=wheel,
+            with_setuptools=setuptools,
+        )
+        yield VirtualEnv(venv_dir, venv_dir)
+
+
 class MockEnv(NullEnv):
     def __init__(
         self,