From 847d53ee9d63712499eb8e34dddc185b0a2fe41d Mon Sep 17 00:00:00 2001
From: Manlio Perillo <manlio.perillo@gmail.com>
Date: Mon, 4 Dec 2023 12:13:36 +0100
Subject: [PATCH 1/2] flit: improve the --python option

pip --python option can take both the path to a Python executable or the
path to a virtual environment, greatly improving the user experience.

Teach flit to do the same.
---
 flit/__init__.py                     |  9 +++++++++
 tests/test_find_python_executable.py | 21 +++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/flit/__init__.py b/flit/__init__.py
index 055cfb99..47252839 100644
--- a/flit/__init__.py
+++ b/flit/__init__.py
@@ -26,6 +26,15 @@ def find_python_executable(python: Optional[str] = None) -> str:
         python = os.environ.get("FLIT_INSTALL_PYTHON")
     if not python:
         return sys.executable
+    if os.path.isdir(python):
+        # Assume it's a virtual environment and look for the environment's
+        # Python executable.  This is the same behavior used by pip.
+        #
+        # Try both Unix and Windows paths in case of odd cases like cygwin.
+        for exe in ("bin/python", "Scripts/python.exe"):
+            py = os.path.join(python, exe)
+            if os.path.exists(py):
+                python = py
     if os.path.isabs(python):  # sys.executable is absolute too
         return python
     # get absolute filepath of {python}
diff --git a/tests/test_find_python_executable.py b/tests/test_find_python_executable.py
index 161dc7a2..b3bf563f 100644
--- a/tests/test_find_python_executable.py
+++ b/tests/test_find_python_executable.py
@@ -1,6 +1,7 @@
-import os
+from os.path import isabs, basename, dirname
 import re
 import sys
+import venv
 
 import pytest
 
@@ -20,7 +21,23 @@ def test_abs():
 
 
 def test_find_in_path():
-    assert os.path.isabs(find_python_executable("python"))
+    assert isabs(find_python_executable("python"))
+
+
+def test_env(tmp_path):
+    path = tmp_path / "venv"
+    venv.create(path)
+
+    executable = find_python_executable(path)
+    assert basename(dirname(dirname(executable))) == "venv"
+
+
+def test_env_abs(tmp_path, monkeypatch):
+    path = tmp_path / "venv"
+    venv.create(path)
+
+    monkeypatch.chdir(tmp_path)
+    assert isabs(find_python_executable("venv"))
 
 
 @pytest.mark.parametrize("bad_python_name", ["pyhton", "ls", "."])

From 05133e9c8a6f795aadcc409b8e2a761278e5ff1f Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <takowl@gmail.com>
Date: Sat, 27 Jan 2024 18:45:49 +0000
Subject: [PATCH 2/2] Return Python from venv path and skip which() step

---
 flit/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flit/__init__.py b/flit/__init__.py
index 47252839..68768d29 100644
--- a/flit/__init__.py
+++ b/flit/__init__.py
@@ -34,7 +34,7 @@ def find_python_executable(python: Optional[str] = None) -> str:
         for exe in ("bin/python", "Scripts/python.exe"):
             py = os.path.join(python, exe)
             if os.path.exists(py):
-                python = py
+                return os.path.abspath(py)
     if os.path.isabs(python):  # sys.executable is absolute too
         return python
     # get absolute filepath of {python}