Add warnings.py module (missed in previous commit).

Author: nascheme

Lib/warnings.py

@@ -0,0 +1,99 @@
+import sys
+
+__all__ = [
+    "warn",
+    "warn_explicit",
+    "showwarning",
+    "formatwarning",
+    "filterwarnings",
+    "simplefilter",
+    "resetwarnings",
+    "catch_warnings",
+    "deprecated",
+]
+
+from _py_warnings import (
+    WarningMessage,
+    _DEPRECATED_MSG,
+    _OptionError,
+    _add_filter,
+    _deprecated,
+    _filters_mutated,
+    _filters_mutated_lock_held,
+    _filters_version,
+    _formatwarning_orig,
+    _formatwarnmsg,
+    _formatwarnmsg_impl,
+    _get_context,
+    _get_filters,
+    _getaction,
+    _getcategory,
+    _is_filename_to_skip,
+    _is_internal_filename,
+    _is_internal_frame,
+    _lock,
+    _new_context,
+    _next_external_frame,
+    _processoptions,
+    _set_context,
+    _set_module,
+    _setoption,
+    _setup_defaults,
+    _showwarning_orig,
+    _showwarnmsg,
+    _showwarnmsg_impl,
+    _use_context,
+    _warn_unawaited_coroutine,
+    _warnings_context,
+    catch_warnings,
+    defaultaction,
+    deprecated,
+    filters,
+    filterwarnings,
+    formatwarning,
+    onceregistry,
+    resetwarnings,
+    showwarning,
+    simplefilter,
+    warn,
+    warn_explicit,
+)
+
+try:
+    # Try to use the C extension, this will replace some parts of the
+    # _py_warnings implementation imported above.
+    from _warnings import (
+        _acquire_lock,
+        _defaultaction as defaultaction,
+        _filters_mutated_lock_held,
+        _onceregistry as onceregistry,
+        _release_lock,
+        _warnings_context,
+        filters,
+        warn,
+        warn_explicit,
+    )
+
+    _warnings_defaults = True
+
+    class _Lock:
+        def __enter__(self):
+            _acquire_lock()
+            return self
+
+        def __exit__(self, *args):
+            _release_lock()
+
+    _lock = _Lock()
+except ImportError:
+    _warnings_defaults = False
+
+
+# Module initialization
+_set_module(sys.modules[__name__])
+_processoptions(sys.warnoptions)
+if not _warnings_defaults:
+    _setup_defaults()
+
+del _warnings_defaults
+del _setup_defaults