gh-120417: Add #noqa to used imports in the stdlib (#120421)

Tools such as ruff can ignore "imported but unused" warnings if a
line ends with "# noqa: F401". It avoids the temptation to remove
an import which is used effectively.

Author: vstinner

Lib/_pyio.py

@@ -16,7 +16,7 @@
     _setmode = None
 
 import io
-from io import (__all__, SEEK_SET, SEEK_CUR, SEEK_END)
+from io import (__all__, SEEK_SET, SEEK_CUR, SEEK_END)  # noqa: F401
 
 valid_seek_flags = {0, 1, 2}  # Hardwired values
 if hasattr(os, 'SEEK_HOLE') :

Lib/code.py

@@ -355,7 +355,7 @@ def interact(banner=None, readfunc=None, local=None, exitmsg=None, local_exit=Fa
         console.raw_input = readfunc
     else:
         try:
-            import readline
+            import readline  # noqa: F401
         except ImportError:
             pass
     console.interact(banner, exitmsg)

Lib/codecs.py

@@ -1129,4 +1129,4 @@ def make_encoding_map(decoding_map):
 # package
 _false = 0
 if _false:
-    import encodings
+    import encodings  # noqa: F401

Lib/collections/__init__.py

@@ -46,7 +46,8 @@
     _collections_abc.MutableSequence.register(deque)
 
 try:
-    from _collections import _deque_iterator
+    # Expose _deque_iterator to support pickling deque iterators
+    from _collections import _deque_iterator  # noqa: F401
 except ImportError:
     pass
 

Lib/concurrent/futures/process.py

@@ -589,7 +589,7 @@ def _check_system_limits():
             raise NotImplementedError(_system_limited)
     _system_limits_checked = True
     try:
-        import multiprocessing.synchronize
+        import multiprocessing.synchronize  # noqa: F401
     except ImportError:
         _system_limited = (
             "This Python build lacks multiprocessing.synchronize, usually due "

Lib/curses/__init__.py

@@ -53,7 +53,7 @@ def start_color():
 try:
     has_key
 except NameError:
-    from .has_key import has_key
+    from .has_key import has_key  # noqa: F401
 
 # Wrapper for the entire curses-based application.  Runs a function which
 # should be the rest of your curses-based application.  If the application

Lib/datetime.py

@@ -1,9 +1,9 @@
 try:
     from _datetime import *
-    from _datetime import __doc__
+    from _datetime import __doc__  # noqa: F401
 except ImportError:
     from _pydatetime import *
-    from _pydatetime import __doc__
+    from _pydatetime import __doc__  # noqa: F401
 
 __all__ = ("date", "datetime", "time", "timedelta", "timezone", "tzinfo",
            "MINYEAR", "MAXYEAR", "UTC")

Lib/decimal.py

@@ -100,9 +100,9 @@
 
 try:
     from _decimal import *
-    from _decimal import __version__
-    from _decimal import __libmpdec_version__
+    from _decimal import __version__  # noqa: F401
+    from _decimal import __libmpdec_version__  # noqa: F401
 except ImportError:
     from _pydecimal import *
-    from _pydecimal import __version__
-    from _pydecimal import __libmpdec_version__
+    from _pydecimal import __version__  # noqa: F401
+    from _pydecimal import __libmpdec_version__  # noqa: F401

Lib/hashlib.py

@@ -187,7 +187,7 @@ def __hash_new(name, data=b'', **kwargs):
 
 try:
     # OpenSSL's scrypt requires OpenSSL 1.1+
-    from _hashlib import scrypt
+    from _hashlib import scrypt  # noqa: F401
 except ImportError:
     pass
 

Lib/lzma.py

@@ -25,7 +25,7 @@
 import io
 import os
 from _lzma import *
-from _lzma import _encode_filter_properties, _decode_filter_properties
+from _lzma import _encode_filter_properties, _decode_filter_properties  # noqa: F401
 import _compression