bpo-32262: Fix codestyle; use f-strings formatting where necessary.

Lib/asyncio/__init__.py

@@ -1,5 +1,7 @@
 """The asyncio package, tracking PEP 3156."""
 
+# flake8: noqa
+
 import sys
 
 # This relies on each of the submodules having an __all__ variable.

Lib/asyncio/base_events.py

@@ -36,7 +36,7 @@
 from .log import logger
 
 
-__all__ = ['BaseEventLoop']
+__all__ = 'BaseEventLoop',
 
 
 # Minimum number of _scheduled timer handles before cleanup of
@@ -173,8 +173,7 @@ def _ensure_resolved(address, *, family=0, type=socket.SOCK_STREAM, proto=0,
 
 def _run_until_complete_cb(fut):
     exc = fut._exception
-    if (isinstance(exc, BaseException)
-    and not isinstance(exc, Exception)):
+    if isinstance(exc, BaseException) and not isinstance(exc, Exception):
         # Issue #22429: run_forever() already finished, no need to
         # stop it.
         return
@@ -190,7 +189,7 @@ def __init__(self, loop, sockets):
         self._waiters = []
 
     def __repr__(self):
-        return '<%s sockets=%r>' % (self.__class__.__name__, self.sockets)
+        return f'<{self.__class__.__name__} sockets={self.sockets!r}>'
 
     def _attach(self):
         assert self.sockets is not None
@@ -262,9 +261,10 @@ def __init__(self):
         self._asyncgens_shutdown_called = False
 
     def __repr__(self):
-        return ('<%s running=%s closed=%s debug=%s>'
-                % (self.__class__.__name__, self.is_running(),
-                   self.is_closed(), self.get_debug()))
+        return (
+            f'<{self.__class__.__name__} running={self.is_running()} '
+            f'closed={self.is_closed()} debug={self.get_debug()}>'
+        )
 
     def create_future(self):
         """Create a Future object attached to the loop."""
@@ -362,8 +362,8 @@ def _asyncgen_finalizer_hook(self, agen):
     def _asyncgen_firstiter_hook(self, agen):
         if self._asyncgens_shutdown_called:
             warnings.warn(
-                "asynchronous generator {!r} was scheduled after "
-                "loop.shutdown_asyncgens() call".format(agen),
+                f"asynchronous generator {agen!r} was scheduled after "
+                f"loop.shutdown_asyncgens() call",
                 ResourceWarning, source=self)
 
         self._asyncgens.add(agen)
@@ -388,8 +388,8 @@ async def shutdown_asyncgens(self):
         for result, agen in zip(results, closing_agens):
             if isinstance(result, Exception):
                 self.call_exception_handler({
-                    'message': 'an error occurred during closing of '
-                               'asynchronous generator {!r}'.format(agen),
+                    'message': f'an error occurred during closing of '
+                               f'asynchronous generator {agen!r}',
                     'exception': result,
                     'asyncgen': agen
                 })
@@ -495,7 +495,7 @@ def is_closed(self):
 
     def __del__(self):
         if not self.is_closed():
-            warnings.warn("unclosed event loop %r" % self, ResourceWarning,
+            warnings.warn(f"unclosed event loop {self!r}", ResourceWarning,
                           source=self)
             if not self.is_running():
                 self.close()
@@ -573,12 +573,11 @@ def _check_callback(self, callback, method):
         if (coroutines.iscoroutine(callback) or
                 coroutines.iscoroutinefunction(callback)):
             raise TypeError(
-                "coroutines cannot be used with {}()".format(method))
+                f"coroutines cannot be used with {method}()")
         if not callable(callback):
             raise TypeError(
-                'a callable object was expected by {}(), got {!r}'.format(
-                    method, callback))
-
+                f'a callable object was expected by {method}(), '
+                f'got {callback!r}')
 
     def _call_soon(self, callback, args):
         handle = events.Handle(callback, args, self)
@@ -630,24 +629,23 @@ def set_default_executor(self, executor):
         self._default_executor = executor
 
     def _getaddrinfo_debug(self, host, port, family, type, proto, flags):
-        msg = ["%s:%r" % (host, port)]
+        msg = [f"{host}:{port!r}"]
         if family:
-            msg.append('family=%r' % family)
+            msg.append(f'family={family!r}' % family)
         if type:
-            msg.append('type=%r' % type)
+            msg.append(f'type={type!r}')
         if proto:
-            msg.append('proto=%r' % proto)
+            msg.append(f'proto={proto!r}')
         if flags:
-            msg.append('flags=%r' % flags)
+            msg.append(f'flags={flags!r}')
         msg = ', '.join(msg)
         logger.debug('Get address info %s', msg)
 
         t0 = self.time()
         addrinfo = socket.getaddrinfo(host, port, family, type, proto, flags)
         dt = self.time() - t0
 
-        msg = ('Getting address info %s took %.3f ms: %r'
-               % (msg, dt * 1e3, addrinfo))
+        msg = f'Getting address info {msg} took {dt * 1e3:.3f}ms: {addrinfo!r}'
         if dt >= self.slow_callback_duration:
             logger.info(msg)
         else:
@@ -738,11 +736,12 @@ async def create_connection(self, protocol_factory, host=None, port=None,
                                 sock.bind(laddr)
                                 break
                             except OSError as exc:
-                                exc = OSError(
-                                    exc.errno, 'error while '
-                                    'attempting to bind on address '
-                                    '{!r}: {}'.format(
-                                        laddr, exc.strerror.lower()))
+                                msg = (
+                                    f'error while attempting to bind on '
+                                    f'address {laddr!r}: '
+                                    f'{exc.strerror.lower()}'
+                                )
+                                exc = OSError(exc.errno, msg)
                                 exceptions.append(exc)
                         else:
                             sock.close()
@@ -786,7 +785,7 @@ async def create_connection(self, protocol_factory, host=None, port=None,
                 # Disallowing AF_UNIX in this method, breaks backwards
                 # compatibility.
                 raise ValueError(
-                    'A Stream Socket was expected, got {!r}'.format(sock))
+                    f'A Stream Socket was expected, got {sock!r}')
 
         transport, protocol = await self._create_connection_transport(
             sock, protocol_factory, ssl, server_hostname)
@@ -830,7 +829,7 @@ async def create_datagram_endpoint(self, protocol_factory,
         if sock is not None:
             if not _is_dgram_socket(sock):
                 raise ValueError(
-                    'A UDP Socket was expected, got {!r}'.format(sock))
+                    f'A UDP Socket was expected, got {sock!r}')
             if (local_addr or remote_addr or
                     family or proto or flags or
                     reuse_address or reuse_port or allow_broadcast):
@@ -839,11 +838,10 @@ async def create_datagram_endpoint(self, protocol_factory,
                             family=family, proto=proto, flags=flags,
                             reuse_address=reuse_address, reuse_port=reuse_port,
                             allow_broadcast=allow_broadcast)
-                problems = ', '.join(
-                    '{}={}'.format(k, v) for k, v in opts.items() if v)
+                problems = ', '.join(f'{k}={v}' for k, v in opts.items() if v)
                 raise ValueError(
-                    'socket modifier keyword arguments can not be used '
-                    'when sock is specified. ({})'.format(problems))
+                    f'socket modifier keyword arguments can not be used '
+                    f'when sock is specified. ({problems})')
             sock.setblocking(False)
             r_addr = None
         else:
@@ -953,7 +951,7 @@ async def _create_server_getaddrinfo(self, host, port, family, flags):
                                        type=socket.SOCK_STREAM,
                                        flags=flags, loop=self)
         if not infos:
-            raise OSError('getaddrinfo({!r}) returned empty list'.format(host))
+            raise OSError(f'getaddrinfo({host!r}) returned empty list')
         return infos
 
     async def create_server(self, protocol_factory, host=None, port=None,
@@ -967,8 +965,8 @@ async def create_server(self, protocol_factory, host=None, port=None,
                             reuse_port=None):
         """Create a TCP server.
 
-        The host parameter can be a string, in that case the TCP server is bound
-        to host and port.
+        The host parameter can be a string, in that case the TCP server is
+        bound to host and port.
 
         The host parameter can also be a sequence of strings and in that case
         the TCP server is bound to all hosts of the sequence. If a host
@@ -1046,8 +1044,7 @@ async def create_server(self, protocol_factory, host=None, port=None,
             if sock is None:
                 raise ValueError('Neither host/port nor sock were specified')
             if not _is_stream_socket(sock):
-                raise ValueError(
-                    'A Stream Socket was expected, got {!r}'.format(sock))
+                raise ValueError(f'A Stream Socket was expected, got {sock!r}')
             sockets = [sock]
 
         server = Server(self, sockets)
@@ -1070,8 +1067,7 @@ async def connect_accepted_socket(self, protocol_factory, sock,
         returns a (transport, protocol) pair.
         """
         if not _is_stream_socket(sock):
-            raise ValueError(
-                'A Stream Socket was expected, got {!r}'.format(sock))
+            raise ValueError(f'A Stream Socket was expected, got {sock!r}')
 
         transport, protocol = await self._create_connection_transport(
             sock, protocol_factory, ssl, '', server_side=True)
@@ -1117,14 +1113,14 @@ async def connect_write_pipe(self, protocol_factory, pipe):
     def _log_subprocess(self, msg, stdin, stdout, stderr):
         info = [msg]
         if stdin is not None:
-            info.append('stdin=%s' % _format_pipe(stdin))
+            info.append(f'stdin={_format_pipe(stdin)}')
         if stdout is not None and stderr == subprocess.STDOUT:
-            info.append('stdout=stderr=%s' % _format_pipe(stdout))
+            info.append(f'stdout=stderr={_format_pipe(stdout)}')
         else:
             if stdout is not None:
-                info.append('stdout=%s' % _format_pipe(stdout))
+                info.append(f'stdout={_format_pipe(stdout)}')
             if stderr is not None:
-                info.append('stderr=%s' % _format_pipe(stderr))
+                info.append(f'stderr={_format_pipe(stderr)}')
         logger.debug(' '.join(info))
 
     async def subprocess_shell(self, protocol_factory, cmd, *,
@@ -1167,14 +1163,14 @@ async def subprocess_exec(self, protocol_factory, program, *args,
         popen_args = (program,) + args
         for arg in popen_args:
             if not isinstance(arg, (str, bytes)):
-                raise TypeError("program arguments must be "
-                                "a bytes or text string, not %s"
-                                % type(arg).__name__)
+                raise TypeError(
+                    f"program arguments must be a bytes or text string, "
+                    f"not {type(arg).__name__}")
         protocol = protocol_factory()
         if self._debug:
             # don't log parameters: they may contain sensitive information
             # (password) and may be too long
-            debug_log = 'execute program %r' % program
+            debug_log = f'execute program {program!r}'
             self._log_subprocess(debug_log, stdin, stdout, stderr)
         transport = await self._make_subprocess_transport(
             protocol, popen_args, False, stdin, stdout, stderr,
@@ -1201,8 +1197,8 @@ def set_exception_handler(self, handler):
         documentation for details about context).
         """
         if handler is not None and not callable(handler):
-            raise TypeError('A callable object or None is expected, '
-                            'got {!r}'.format(handler))
+            raise TypeError(f'A callable object or None is expected, '
+                            f'got {handler!r}')
         self._exception_handler = handler
 
     def default_exception_handler(self, context):
@@ -1230,10 +1226,11 @@ def default_exception_handler(self, context):
         else:
             exc_info = False
 
-        if ('source_traceback' not in context
-        and self._current_handle is not None
-        and self._current_handle._source_traceback):
-            context['handle_traceback'] = self._current_handle._source_traceback
+        if ('source_traceback' not in context and
+                self._current_handle is not None and
+                self._current_handle._source_traceback):
+            context['handle_traceback'] = \
+                self._current_handle._source_traceback
 
         log_lines = [message]
         for key in sorted(context):
@@ -1250,7 +1247,7 @@ def default_exception_handler(self, context):
                 value += tb.rstrip()
             else:
                 value = repr(value)
-            log_lines.append('{}: {}'.format(key, value))
+            log_lines.append(f'{key}: {value}')
 
         logger.error('\n'.join(log_lines), exc_info=exc_info)
 
@@ -1438,18 +1435,19 @@ def _set_coroutine_wrapper(self, enabled):
         if enabled:
             if current_wrapper not in (None, wrapper):
                 warnings.warn(
-                    "loop.set_debug(True): cannot set debug coroutine "
-                    "wrapper; another wrapper is already set %r" %
-                    current_wrapper, RuntimeWarning)
+                    f"loop.set_debug(True): cannot set debug coroutine "
+                    f"wrapper; another wrapper is already set "
+                    f"{current_wrapper!r}",
+                    RuntimeWarning)
             else:
                 set_wrapper(wrapper)
                 self._coroutine_wrapper_set = True
         else:
             if current_wrapper not in (None, wrapper):
                 warnings.warn(
-                    "loop.set_debug(False): cannot unset debug coroutine "
-                    "wrapper; another wrapper was set %r" %
-                    current_wrapper, RuntimeWarning)
+                    f"loop.set_debug(False): cannot unset debug coroutine "
+                    f"wrapper; another wrapper was set {current_wrapper!r}",
+                    RuntimeWarning)
             else:
                 set_wrapper(None)
                 self._coroutine_wrapper_set = False

Lib/asyncio/base_futures.py

@@ -1,4 +1,4 @@
-__all__ = []
+__all__ = ()
 
 import concurrent.futures._base
 import reprlib
@@ -48,7 +48,7 @@ def format_cb(callback):
         cb = '{}, <{} more>, {}'.format(format_cb(cb[0]),
                                         size - 2,
                                         format_cb(cb[-1]))
-    return 'cb=[%s]' % cb
+    return f'cb=[{cb}]'
 
 
 def _future_repr_info(future):
@@ -57,15 +57,15 @@ def _future_repr_info(future):
     info = [future._state.lower()]
     if future._state == _FINISHED:
         if future._exception is not None:
-            info.append('exception={!r}'.format(future._exception))
+            info.append(f'exception={future._exception!r}')
         else:
             # use reprlib to limit the length of the output, especially
             # for very long strings
             result = reprlib.repr(future._result)
-            info.append('result={}'.format(result))
+            info.append(f'result={result}')
     if future._callbacks:
         info.append(_format_callbacks(future._callbacks))
     if future._source_traceback:
         frame = future._source_traceback[-1]
-        info.append('created at %s:%s' % (frame[0], frame[1]))
+        info.append(f'created at {frame[0]}:{frame[1]}')
     return info