Honor sys.executable unless macOS Framework.

pex/interpreter.py

@@ -69,16 +69,17 @@ class UnknownRequirement(Error):
 
     @classmethod
     def get(cls, binary=None):
+        # type: (Optional[str]) -> PythonIdentity
+
         # N.B.: We should not need to look past `sys.executable` to learn the current interpreter's
         # executable path, but on OSX there has been a bug where the `sys.executable` reported is
         # _not_ the path of the current interpreter executable:
-        # https://bugs.python.org/issue22490#msg283859
-        if binary and binary != sys.executable:
-            TRACER.log(
-                "Identifying interpreter found at {} which reports an incorrect sys.executable of "
-                "{}.".format(binary, sys.executable),
-                V=9,
-            )
+        #   https://bugs.python.org/issue22490#msg283859
+        # That case is distinguished by the presence of a `__PYVENV_LAUNCHER__` environment
+        # variable as detailed in the Python bug linked above.
+        if binary and binary != sys.executable and "__PYVENV_LAUNCHER__" not in os.environ:
+            # Here we assume sys.executable is accurate and binary is something like a pyenv shim.
+            binary = sys.executable
 
         supported_tags = tuple(tags.sys_tags())
         preferred_tag = supported_tags[0]

pex/testing.py

@@ -13,6 +13,7 @@
 from textwrap import dedent
 
 from pex.common import open_zip, safe_mkdir, safe_mkdtemp, safe_rmtree, temporary_dir, touch
+from pex.compatibility import to_unicode
 from pex.distribution_target import DistributionTarget
 from pex.executor import Executor
 from pex.interpreter import PythonInterpreter
@@ -27,6 +28,7 @@
 if TYPE_CHECKING:
     from typing import (
         Any,
+        Callable,
         Dict,
         Iterable,
         Iterator,
@@ -416,33 +418,41 @@ def bootstrap_python_installer(dest):
 
 
 def ensure_python_distribution(version):
-    # type: (str) -> Tuple[str, str]
+    # type: (str) -> Tuple[str, str, Callable[[Iterable[str]], Text]]
     if version not in _VERSIONS:
         raise ValueError("Please constrain version to one of {}".format(_VERSIONS))
 
     pyenv_root = os.path.join(os.getcwd(), ".pyenv_test")
     interpreter_location = os.path.join(pyenv_root, "versions", version)
+
     pyenv = os.path.join(pyenv_root, "bin", "pyenv")
+    pyenv_env = os.environ.copy()
+    pyenv_env["PYENV_ROOT"] = pyenv_root
+
     pip = os.path.join(interpreter_location, "bin", "pip")
 
     if not os.path.exists(os.path.join(pyenv_root, _INTERPRETER_SET_FINGERPRINT)):
         bootstrap_python_installer(pyenv_root)
 
     if not os.path.exists(interpreter_location):
-        env = os.environ.copy()
-        env["PYENV_ROOT"] = pyenv_root
+        env = pyenv_env.copy()
         if sys.platform.lower() == "linux":
             env["CONFIGURE_OPTS"] = "--enable-shared"
         subprocess.check_call([pyenv, "install", "--keep", version], env=env)
         subprocess.check_call([pip, "install", "-U", "pip"])
 
     python = os.path.join(interpreter_location, "bin", "python" + version[0:3])
-    return python, pip
+
+    def run_pyenv(args):
+        # type: (Iterable[str]) -> Text
+        return to_unicode(subprocess.check_output([pyenv] + list(args), env=pyenv_env))
+
+    return python, pip, run_pyenv
 
 
 def ensure_python_interpreter(version):
     # type: (str) -> str
-    python, _ = ensure_python_distribution(version)
+    python, _, _ = ensure_python_distribution(version)
     return python
 
 

tests/test_integration.py

@@ -1970,7 +1970,7 @@ def test_issues_745_extras_isolation():
     # type: () -> None
     # Here we ensure one of our extras, `subprocess32`, is properly isolated in the transition from
     # pex bootstrapping where it is imported by `pex.executor` to execution of user code.
-    python, pip = ensure_python_distribution(PY27)
+    python, pip, _ = ensure_python_distribution(PY27)
     subprocess.check_call([pip, "install", "subprocess32"])
     with temporary_dir() as td:
         src_dir = os.path.join(td, "src")
@@ -2046,7 +2046,7 @@ def write_pth(pth_path, sitedir):
 
 
 def test_issues_1025_extras_isolation(issues_1025_pth):
-    python, pip = ensure_python_distribution(PY36)
+    python, pip, _ = ensure_python_distribution(PY36)
     interpreter = PythonInterpreter.from_binary(python)
     _, stdout, _ = interpreter.execute(args=["-c", "import site; print(site.getsitepackages()[0])"])
     with temporary_dir() as tmpdir:

tests/test_interpreter.py

@@ -9,8 +9,16 @@
 from pex.common import temporary_dir, touch
 from pex.compatibility import PY3
 from pex.interpreter import PythonInterpreter
-from pex.testing import PY27, PY35, ensure_python_interpreter
+from pex.testing import (
+    PY27,
+    PY35,
+    PY36,
+    ensure_python_distribution,
+    ensure_python_interpreter,
+    environment_as,
+)
 from pex.typing import TYPE_CHECKING
+from pex.variables import ENV
 
 try:
     from mock import patch
@@ -176,3 +184,38 @@ def test_iter_interpreter_path_filter_symlink(self, test_interpreter1, test_inte
                 )
             )
             assert os.path.basename(expected_interpreter.binary) != "jake"
+
+    def test_pyenv_shims(self):
+        # type: () -> None
+        py35, _, run_pyenv = ensure_python_distribution(PY35)
+        py36, _, _ = ensure_python_distribution(PY36)
+
+        pyenv_root = str(run_pyenv(["root"]).strip())
+        pyenv_shims = os.path.join(pyenv_root, "shims")
+
+        def pyenv_global(*versions):
+            run_pyenv(["global"] + list(versions))
+
+        def assert_shim(shim_name, expected_binary_path):
+            python = PythonInterpreter.from_binary(os.path.join(pyenv_shims, shim_name))
+            assert expected_binary_path == python.binary
+
+        with temporary_dir() as pex_root:
+            with ENV.patch(PEX_ROOT=pex_root) as pex_env:
+                with environment_as(PYENV_ROOT=pyenv_root, **pex_env):
+                    pyenv_global(PY35, PY36)
+                    assert_shim("python3", py35)
+
+                    pyenv_global(PY36, PY35)
+                    # The python3 shim is now pointing at python3.6 but the Pex cache has a valid
+                    # entry for the old python3.5 association (the interpreter still exists.)
+                    assert_shim("python3", py35)
+
+                    # The shim pointer is now invalid since python3.5 was uninstalled and so should
+                    # be re-read.
+                    py35_deleted = "{}.uninstalled".format(py35)
+                    os.rename(py35, py35_deleted)
+                    try:
+                        assert_shim("python3", py36)
+                    finally:
+                        os.rename(py35_deleted, py35)