fix windows powershell activate encoding problem

src/virtualenv/activation/via_template.py

@@ -47,8 +47,10 @@ def _generate(self, replacements, templates, to_folder, creator):
             # errors when the dest is not writable
             if dest.exists():
                 dest.unlink()
+            # Powershell assumes Windows 1252 encoding when reading files without BOM
+            encoding = "utf-8-sig" if template.endswith(".ps1") else "utf-8"
             # use write_bytes to avoid platform specific line normalization (\n -> \r\n)
-            dest.write_bytes(text.encode("utf-8"))
+            dest.write_bytes(text.encode(encoding))
             generated.append(dest)
         return generated
 

tests/unit/activation/test_powershell.py

@@ -19,14 +19,13 @@ def __init__(self, session) -> None:
             self._version_cmd = [cmd, "-c", "$PSVersionTable"]
             self._invoke_script = [cmd, "-ExecutionPolicy", "ByPass", "-File"]
             self.activate_cmd = "."
-            self.script_encoding = "utf-16"
+            self.script_encoding = "utf-8-sig"
 
         def quote(self, s):
             """powershell double quote needed for quotes within single quotes"""
             return quote(s).replace('"', '""')
 
         def _get_test_lines(self, activate_script):
-            # for BATCH utf-8 support need change the character code page to 650001
             return super()._get_test_lines(activate_script)
 
         def invoke_script(self):