tools: Reinstall virtualenv if it is broken

Closes https://github.com/espressif/esp-idf/issues/6656

tools/idf_tools.py

@@ -1348,14 +1348,30 @@ def get_wheels_dir():  # type: () -> Optional[str]
 
 
 def action_install_python_env(args):  # type: ignore
+    reinstall = args.reinstall
     idf_python_env_path, _, virtualenv_python = get_python_env_path()
 
     is_virtualenv = hasattr(sys, 'real_prefix') or (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix)
-    if is_virtualenv and (not os.path.exists(idf_python_env_path) or args.reinstall):
+    if is_virtualenv and (not os.path.exists(idf_python_env_path) or reinstall):
         fatal('This script was called from a virtual environment, can not create a virtual environment again')
         raise SystemExit(1)
 
-    if args.reinstall and os.path.exists(idf_python_env_path):
+    if os.path.exists(virtualenv_python):
+        try:
+            subprocess.check_call([virtualenv_python, '--version'], stdout=sys.stdout, stderr=sys.stderr)
+        except subprocess.CalledProcessError:
+            # At this point we can reinstall the virtual environment if it is non-functional. This can happen at least
+            # when the Python interpreter was removed which was used to create the virtual environment.
+            reinstall = True
+
+        try:
+            subprocess.check_call([virtualenv_python, '-m', 'pip', '--version'], stdout=sys.stdout, stderr=sys.stderr)
+        except subprocess.CalledProcessError:
+            warn('PIP is not available in the virtual environment.')
+            # Reinstallation of the virtual environment could help if PIP was installed for the main Python
+            reinstall = True
+
+    if reinstall and os.path.exists(idf_python_env_path):
         warn('Removing the existing Python environment in {}'.format(idf_python_env_path))
         shutil.rmtree(idf_python_env_path)