gh-76912: Raise OSError from any failure in getpass.getuser()

Doc/library/getpass.rst

@@ -46,7 +46,7 @@ The :mod:`getpass` module provides two functions:
    :envvar:`USER`, :envvar:`!LNAME` and :envvar:`USERNAME`, in order, and
    returns the value of the first one which is set to a non-empty string.  If
    none are set, the login name from the password database is returned on
-   systems which support the :mod:`pwd` module, otherwise, an exception is
-   raised.
+   systems which support the :mod:`pwd` module, otherwise, an :exc:`OSError`
+   is raised.
 
    In general, this function should be preferred over :func:`os.getlogin()`.

Doc/whatsnew/3.13.rst

@@ -1017,6 +1017,10 @@ Changes in the Python API
   recomended in the documentation.
   (Contributed by Serhiy Storchaka in :gh:`106672`.)
 
+* An :exc:`OSError` is now raised by :func:`getpass.getuser` for any failure to
+  retrieve a username, instead of :exc:`ImportError` on non-Unix platforms or
+  :exc:`KeyError` on Unix platforms where the password database is empty.
+
 
 Build Changes
 =============

Lib/getpass.py

@@ -156,17 +156,25 @@ def getuser():
 
     First try various environment variables, then the password
     database.  This works on Windows as long as USERNAME is set.
+    Any failure to find a username raises OSError.
 
+    .. versionchanged:: 3.13
+        Failure to find a username raises :exc:`OSError` instead of
+        :exc:`ImportError` on non-Unix platforms and instead of
+        :exc:`KeyError` on Unix platforms if the password database is empty.
     """
 
     for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
         user = os.environ.get(name)
         if user:
             return user
 
-    # If this fails, the exception will "explain" why
-    import pwd
-    return pwd.getpwuid(os.getuid())[0]
+    try:
+        import pwd
+        return pwd.getpwuid(os.getuid())[0]
+    except (ImportError, KeyError) as e:
+        raise OSError('No username set in the environment') from e
+
 
 # Bind the name getpass to the appropriate function
 try:

Lib/test/test_getpass.py

@@ -26,7 +26,7 @@ def test_username_priorities_of_env_values(self, environ):
         environ.get.return_value = None
         try:
             getpass.getuser()
-        except ImportError: # in case there's no pwd module
+        except OSError:  # in case there's no pwd module
             pass
         except KeyError:
             # current user has no pwd entry
@@ -47,7 +47,7 @@ def test_username_falls_back_to_pwd(self, environ):
                                  getpass.getuser())
                 getpw.assert_called_once_with(42)
         else:
-            self.assertRaises(ImportError, getpass.getuser)
+            self.assertRaises(OSError, getpass.getuser)
 
 
 class GetpassRawinputTest(unittest.TestCase):

Misc/NEWS.d/next/Library/2021-11-23-22-22-49.bpo-32731.kNOASr.rst

@@ -0,0 +1,3 @@
+:func:`getpass.getuser` now raises :exc:`OSError` for all failures rather
+than :exc:`ImportError` on systems lacking the :mod:`pwd` module or
+:exc:`KeyError` if the password database is empty.