From 4302f4e0043177d2fc8c7b2852e2e2054249b432 Mon Sep 17 00:00:00 2001
From: Jesse Schwartzentruber <truber@mozilla.com>
Date: Mon, 29 Mar 2021 16:54:30 -0400
Subject: [PATCH] Use `{env}/bin` instead of `{env}/Scripts` when Python is
 from MSYS2 on Windows.

MSYS2 prefers a Linux filesystem layout, but is otherwise a native
Windows interpreter.

Fixes #1982
---
 CONTRIBUTORS                                 |  1 +
 docs/changelog/1982.bugfix.rst               |  3 +++
 src/tox/config/__init__.py                   |  5 +++++
 src/tox/helper/get_version.py                |  2 ++
 src/tox/interpreters/__init__.py             |  2 ++
 tests/unit/config/test_config.py             | 16 ++++++++++++++++
 tests/unit/interpreters/test_interpreters.py |  4 +++-
 7 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 docs/changelog/1982.bugfix.rst

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 55dd6d1b3e..5be3eaa099 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -48,6 +48,7 @@ Ionel Maries Cristian
 Itxaka Serrano
 Jake Windle
 Jannis Leidel
+Jesse Schwartzentruber
 Joachim Brandon LeBlanc
 Johannes Christ
 John Mark Vandenberg
diff --git a/docs/changelog/1982.bugfix.rst b/docs/changelog/1982.bugfix.rst
new file mode 100644
index 0000000000..6cd703a71c
--- /dev/null
+++ b/docs/changelog/1982.bugfix.rst
@@ -0,0 +1,3 @@
+Distinguish between normal Windows Python and MSYS2 Python when looking for
+virtualenv executable path.  Adds os.sep to :class:`InterpreterInfo`
+- by :user:`jschwartzentruber`
diff --git a/src/tox/config/__init__.py b/src/tox/config/__init__.py
index 278d4b2b6d..5e0c178f6d 100644
--- a/src/tox/config/__init__.py
+++ b/src/tox/config/__init__.py
@@ -1053,6 +1053,11 @@ def get_envbindir(self):
             isinstance(self.python_info, NoInterpreterInfo)
             or tox.INFO.IS_WIN is False
             or self.python_info.implementation == "Jython"
+            or (
+                # this combination is MSYS2
+                tox.INFO.IS_WIN
+                and self.python_info.ossep == "/"
+            )
             or (
                 tox.INFO.IS_WIN
                 and self.python_info.implementation == "PyPy"
diff --git a/src/tox/helper/get_version.py b/src/tox/helper/get_version.py
index b1a8455a4a..b39660de69 100644
--- a/src/tox/helper/get_version.py
+++ b/src/tox/helper/get_version.py
@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 import json
+import os
 import platform
 import sys
 
@@ -11,6 +12,7 @@
     "version": sys.version,
     "is_64": sys.maxsize > 2 ** 32,
     "sysplatform": sys.platform,
+    "ossep": os.sep,
     "extra_version_info": getattr(sys, "pypy_version_info", None),
 }
 info_as_dump = json.dumps(info)
diff --git a/src/tox/interpreters/__init__.py b/src/tox/interpreters/__init__.py
index a31314004e..d2b0044ec4 100644
--- a/src/tox/interpreters/__init__.py
+++ b/src/tox/interpreters/__init__.py
@@ -103,6 +103,7 @@ def __init__(
         version_info,
         sysplatform,
         is_64,
+        ossep,
         extra_version_info,
     ):
         self.implementation = implementation
@@ -111,6 +112,7 @@ def __init__(
         self.version_info = version_info
         self.sysplatform = sysplatform
         self.is_64 = is_64
+        self.ossep = ossep
         self.extra_version_info = extra_version_info
 
     def __str__(self):
diff --git a/tests/unit/config/test_config.py b/tests/unit/config/test_config.py
index b4bd24fb56..cfc564c018 100644
--- a/tests/unit/config/test_config.py
+++ b/tests/unit/config/test_config.py
@@ -1469,6 +1469,22 @@ def test_envbindir_jython(self, newconfig, bp):
         if bp == "jython":
             assert envconfig.envpython == envconfig.envbindir.join(bp)
 
+    @pytest.mark.parametrize("sep, bindir", [("\\", "Scripts"), ("/", "bin")])
+    def test_envbindir_win(self, newconfig, monkeypatch, sep, bindir):
+        monkeypatch.setattr(tox.INFO, "IS_WIN", True)
+        config = newconfig(
+            """
+            [testenv]
+            basepython=python
+        """,
+        )
+        assert len(config.envconfigs) == 1
+        envconfig = config.envconfigs["python"]
+        envconfig.python_info.ossep = sep  # force os.sep result
+        # on win32 with msys2, virtualenv uses "bin" for python
+        assert envconfig.envbindir.basename == bindir
+        assert envconfig.envpython == envconfig.envbindir.join("python")
+
     @pytest.mark.parametrize("plat", ["win32", "linux2"])
     def test_passenv_as_multiline_list(self, newconfig, monkeypatch, plat):
         monkeypatch.setattr(tox.INFO, "IS_WIN", plat == "win32")
diff --git a/tests/unit/interpreters/test_interpreters.py b/tests/unit/interpreters/test_interpreters.py
index fd364bafb1..298a4aae42 100644
--- a/tests/unit/interpreters/test_interpreters.py
+++ b/tests/unit/interpreters/test_interpreters.py
@@ -192,7 +192,9 @@ def info(
         version_info="my-version-info",
         sysplatform="my-sys-platform",
     ):
-        return InterpreterInfo(implementation, executable, version_info, sysplatform, True, None)
+        return InterpreterInfo(
+            implementation, executable, version_info, sysplatform, True, "/", None
+        )
 
     def test_data(self):
         x = self.info("larry", "moe", "shemp", "curly")