GeezerVison

Several pathlib.Path and pathlib.PurePath return new Path and PurePath objects. A subclass of one of those classes returns objects that are instances of the subclass, but the subclass's new() and init() functions are not called. A subclass has to override Path._init() or PurePath._init() to perform custom initialization for these returned objects in addition to its init() function.

This patch reworks the Path and PurePath object creation processes to ensure that the new() and init() functions in subclasses get called. It moves the object creation process from PurePath._from_parts() and PurePath._from_parsed_parts() to PurePath.init() and Path.init(), and marks the two functions with deprecation warnings.

https://bugs.python.org/issue41109