gh-109940: Respect VIRTUAL_ENV_DISABLE_PROMPT in activate.bat (GH-151215)

(cherry picked from commit 7a014f4)

Co-authored-by: Harjoth Khara <harjoth.khara@gmail.com>

Author: harjothkhara

Lib/test/test_venv.py

@@ -592,6 +592,51 @@ def test_unicode_in_batch_file(self):
         )
         self.assertEqual(out.strip(), '0')
 
+    @unittest.skipUnless(os.name == 'nt', 'only relevant on Windows')
+    def test_activate_bat_respects_disable_prompt(self):
+        rmtree(self.env_dir)
+        env_dir = os.path.join(os.path.realpath(self.env_dir), 'venv')
+        builder = venv.EnvBuilder(clear=True)
+        builder.create(env_dir)
+        activate = os.path.join(env_dir, self.bindir, 'activate.bat')
+        test_batch = os.path.join(self.env_dir, 'test_disable_prompt.bat')
+        with open(test_batch, "w") as f:
+            f.write('@echo off\n'
+                    'set "PROMPT=base$G"\n'
+                    'set "VIRTUAL_ENV_DISABLE_PROMPT=1"\n'
+                    f'call "{activate}"\n'
+                    'echo ACTIVE_PROMPT:%PROMPT%\n'
+                    'echo VIRTUAL_ENV:%VIRTUAL_ENV%\n'
+                    'set "PROMPT=changed$G"\n'
+                    'call deactivate\n'
+                    'echo FINAL_PROMPT:%PROMPT%\n')
+        out, err = check_output([test_batch])
+        lines = out.splitlines()
+        self.assertEqual(lines[0], b'ACTIVE_PROMPT:base$G')
+        self.assertEndsWith(lines[1], os.fsencode(env_dir))
+        self.assertEqual(lines[2], b'FINAL_PROMPT:changed$G')
+
+    @unittest.skipUnless(os.name == 'nt', 'only relevant on Windows')
+    def test_activate_bat_prefixes_prompt_by_default(self):
+        rmtree(self.env_dir)
+        env_dir = os.path.join(os.path.realpath(self.env_dir), 'venv')
+        builder = venv.EnvBuilder(clear=True)
+        builder.create(env_dir)
+        activate = os.path.join(env_dir, self.bindir, 'activate.bat')
+        test_batch = os.path.join(self.env_dir, 'test_enable_prompt.bat')
+        with open(test_batch, "w") as f:
+            f.write('@echo off\n'
+                    'set "PROMPT=base) $G"\n'
+                    'set "VIRTUAL_ENV_DISABLE_PROMPT="\n'
+                    f'call "{activate}"\n'
+                    'echo ACTIVE_PROMPT:%PROMPT%\n'
+                    'call deactivate\n'
+                    'echo FINAL_PROMPT:%PROMPT%\n')
+        out, err = check_output([test_batch])
+        lines = out.splitlines()
+        self.assertEqual(lines[0], b'ACTIVE_PROMPT:(venv) base) $G')
+        self.assertEqual(lines[1], b'FINAL_PROMPT:base) $G')
+
     @unittest.skipUnless(os.name == 'nt' and can_symlink(),
                          'symlinks on Windows')
     def test_failed_symlink(self):

Lib/venv/scripts/nt/activate.bat

@@ -13,8 +13,8 @@
 @if defined _OLD_VIRTUAL_PROMPT @set PROMPT=%_OLD_VIRTUAL_PROMPT%
 @if defined _OLD_VIRTUAL_PYTHONHOME @set PYTHONHOME=%_OLD_VIRTUAL_PYTHONHOME%
 
-@set "_OLD_VIRTUAL_PROMPT=%PROMPT%"
-@set "PROMPT=(__VENV_PROMPT__) %PROMPT%"
+@if not defined VIRTUAL_ENV_DISABLE_PROMPT @set "_OLD_VIRTUAL_PROMPT=%PROMPT%"
+@if not defined VIRTUAL_ENV_DISABLE_PROMPT @set "PROMPT=(__VENV_PROMPT__) %PROMPT%"
 
 @if defined PYTHONHOME @set _OLD_VIRTUAL_PYTHONHOME=%PYTHONHOME%
 @set PYTHONHOME=

Misc/NEWS.d/next/Library/2026-06-10-00-00-02.gh-issue-109940.Cx1099.rst

@@ -0,0 +1,2 @@
+Fix Windows :mod:`venv` activation in ``cmd.exe`` to respect
+``VIRTUAL_ENV_DISABLE_PROMPT``.