gh-82874: Convert remaining importlib format uses to f-str.

Lib/importlib/__init__.py

@@ -84,22 +84,21 @@ def find_loader(name, path=None):
     try:
         loader = sys.modules[name].__loader__
         if loader is None:
-            raise ValueError('{}.__loader__ is None'.format(name))
+            raise ValueError('{name}.__loader__ is None')
         else:
             return loader
     except KeyError:
         pass
     except AttributeError:
-        raise ValueError('{}.__loader__ is not set'.format(name)) from None
+        raise ValueError(f'{name}.__loader__ is not set') from None
 
     spec = _bootstrap._find_spec(name, path)
     # We won't worry about malformed specs (missing attributes).
     if spec is None:
         return None
     if spec.loader is None:
         if spec.submodule_search_locations is None:
-            raise ImportError('spec for {} missing loader'.format(name),
-                              name=name)
+            raise ImportError(f'spec for {name} missing loader', name=name)
         raise ImportError('namespace packages do not have loaders',
                           name=name)
     return spec.loader
@@ -116,9 +115,8 @@ def import_module(name, package=None):
     level = 0
     if name.startswith('.'):
         if not package:
-            msg = ("the 'package' argument is required to perform a relative "
-                   "import for {!r}")
-            raise TypeError(msg.format(name))
+            raise TypeError("the 'package' argument is required to perform a "
+                            f"relative import for {name!r}")
         for character in name:
             if character != '.':
                 break
@@ -144,8 +142,7 @@ def reload(module):
             raise TypeError("reload() argument must be a module")
 
     if sys.modules.get(name) is not module:
-        msg = "module {} not in sys.modules"
-        raise ImportError(msg.format(name), name=name)
+        raise ImportError(f"module {name} not in sys.modules", name=name)
     if name in _RELOADING:
         return _RELOADING[name]
     _RELOADING[name] = module
@@ -155,8 +152,7 @@ def reload(module):
             try:
                 parent = sys.modules[parent_name]
             except KeyError:
-                msg = "parent {!r} not in sys.modules"
-                raise ImportError(msg.format(parent_name),
+                raise ImportError(f"parent {parent_name!r} not in sys.modules",
                                   name=parent_name) from None
             else:
                 pkgpath = parent.__path__

Lib/importlib/_bootstrap_external.py

@@ -197,7 +197,7 @@ def _write_atomic(path, data, mode=0o666):
     Be prepared to handle a FileExistsError if concurrent writing of the
     temporary file is attempted."""
     # id() is used to generate a pseudo-random filename.
-    path_tmp = '{}.{}'.format(path, id(path))
+    path_tmp = f'{path}.{id(path)}'
     fd = _os.open(path_tmp,
                   _os.O_EXCL | _os.O_CREAT | _os.O_WRONLY, mode & 0o666)
     try:
@@ -492,8 +492,8 @@ def cache_from_source(path, debug_override=None, *, optimization=None):
     optimization = str(optimization)
     if optimization != '':
         if not optimization.isalnum():
-            raise ValueError('{!r} is not alphanumeric'.format(optimization))
-        almost_filename = '{}.{}{}'.format(almost_filename, _OPT, optimization)
+            raise ValueError(f'{optimization!r} is not alphanumeric')
+        almost_filename = f'{almost_filename}.{_OPT}{optimization}'
     filename = almost_filename + BYTECODE_SUFFIXES[0]
     if sys.pycache_prefix is not None:
         # We need an absolute path to the py file to avoid the possibility of
@@ -651,8 +651,8 @@ def _find_module_shim(self, fullname):
     # return None.
     loader, portions = self.find_loader(fullname)
     if loader is None and len(portions):
-        msg = 'Not importing directory {}: missing __init__'
-        _warnings.warn(msg.format(portions[0]), ImportWarning)
+        msg = f'Not importing directory {portions[0]}: missing __init__'
+        _warnings.warn(msg, ImportWarning)
     return loader
 
 
@@ -750,7 +750,7 @@ def _compile_bytecode(data, name=None, bytecode_path=None, source_path=None):
             _imp._fix_co_filename(code, source_path)
         return code
     else:
-        raise ImportError('Non-code object in {!r}'.format(bytecode_path),
+        raise ImportError(f'Non-code object in {bytecode_path!r}',
                           name=name, path=bytecode_path)
 
 
@@ -951,8 +951,8 @@ def exec_module(self, module):
         """Execute the module."""
         code = self.get_code(module.__name__)
         if code is None:
-            raise ImportError('cannot load module {!r} when get_code() '
-                              'returns None'.format(module.__name__))
+            raise ImportError(f'cannot load module {module.__name__!r} when '
+                              'get_code() returns None')
         _bootstrap._call_with_frames_removed(exec, code, module.__dict__)
 
     def load_module(self, fullname):
@@ -1337,7 +1337,7 @@ def __len__(self):
         return len(self._recalculate())
 
     def __repr__(self):
-        return '_NamespacePath({!r})'.format(self._path)
+        return f'_NamespacePath({self._path!r})'
 
     def __contains__(self, item):
         return item in self._recalculate()
@@ -1678,7 +1678,7 @@ def _fill_cache(self):
             for item in contents:
                 name, dot, suffix = item.partition('.')
                 if dot:
-                    new_name = '{}.{}'.format(name, suffix.lower())
+                    new_name = f'{name}.{suffix.lower()}'
                 else:
                     new_name = name
                 lower_suffix_contents.add(new_name)
@@ -1705,7 +1705,7 @@ def path_hook_for_FileFinder(path):
         return path_hook_for_FileFinder
 
     def __repr__(self):
-        return 'FileFinder({!r})'.format(self.path)
+        return f'FileFinder({self.path!r})'
 
 
 # Import setup ###############################################################

Lib/importlib/resources/_adapters.py

@@ -35,7 +35,7 @@ def _io_wrapper(file, mode='r', *args, **kwargs):
     elif mode == 'rb':
         return file
     raise ValueError(
-        "Invalid mode value '{}', only 'r' and 'rb' are supported".format(mode)
+        f"Invalid mode value '{mode}', only 'r' and 'rb' are supported"
     )
 
 

Lib/importlib/util.py

@@ -63,10 +63,10 @@ def _find_spec_from_path(name, path=None):
         try:
             spec = module.__spec__
         except AttributeError:
-            raise ValueError('{}.__spec__ is not set'.format(name)) from None
+            raise ValueError(f'{name}.__spec__ is not set') from None
         else:
             if spec is None:
-                raise ValueError('{}.__spec__ is None'.format(name))
+                raise ValueError(f'{name}.__spec__ is None')
             return spec
 
 
@@ -108,10 +108,10 @@ def find_spec(name, package=None):
         try:
             spec = module.__spec__
         except AttributeError:
-            raise ValueError('{}.__spec__ is not set'.format(name)) from None
+            raise ValueError(f'{name}.__spec__ is not set') from None
         else:
             if spec is None:
-                raise ValueError('{}.__spec__ is None'.format(name))
+                raise ValueError(f'{name}.__spec__ is None')
             return spec
 
 

Misc/NEWS.d/next/Library/2019-11-04-22-21-27.bpo-38693.w_OAov.rst

@@ -1 +1 @@
-importlib now uses f-strings internally instead of str.format().
+:mod:`importlib` now uses f-strings internally instead of ``str.format``.