Add types to auth.Resolver and its methods

Author: jaraco

twine/auth.py

@@ -2,6 +2,7 @@
 import getpass
 import functools
 import typing
+from typing import Optional, Callable
 
 import keyring
 
@@ -29,7 +30,7 @@ def choose(cls, interactive):
 
     @property  # type: ignore  # https://github.com/python/mypy/issues/1362
     @functools.lru_cache()
-    def username(self):
+    def username(self) -> Optional[str]:
         return utils.get_userpass_value(
             self.input.username,
             self.config,
@@ -39,7 +40,7 @@ def username(self):
 
     @property  # type: ignore  # https://github.com/python/mypy/issues/1362
     @functools.lru_cache()
-    def password(self):
+    def password(self) -> Optional[str]:
         return utils.get_userpass_value(
             self.input.password,
             self.config,
@@ -48,7 +49,7 @@ def password(self):
         )
 
     @property
-    def system(self):
+    def system(self) -> Optional[str]:
         return self.config['repository']
 
     def get_username_from_keyring(self):
@@ -62,28 +63,30 @@ def get_username_from_keyring(self):
         except Exception as exc:
             warnings.warn(str(exc))
 
-    def get_password_from_keyring(self):
+    def get_password_from_keyring(self) -> Optional[str]:
         try:
             return keyring.get_password(self.system, self.username)
         except Exception as exc:
             warnings.warn(str(exc))
+        return None  # TODO: mypy shouldn't require this
+        return None  # any more than it should require this
 
-    def username_from_keyring_or_prompt(self):
+    def username_from_keyring_or_prompt(self) -> str:
         return (
             self.get_username_from_keyring()
             or self.prompt('username', input)
         )
 
-    def password_from_keyring_or_prompt(self):
+    def password_from_keyring_or_prompt(self) -> str:
         return (
             self.get_password_from_keyring()
             or self.prompt('password', getpass.getpass)
         )
 
-    def prompt(self, what, how=None):
+    def prompt(self, what: str, how: Callable) -> str:
         return how(f"Enter your {what}: ")
 
 
 class Private(Resolver):
-    def prompt(self, what, how=None):
+    def prompt(self, what: str, how: Optional[Callable] = None) -> str:
         raise exceptions.NonInteractive(f"Credential not found for {what}.")