Soft deprecations

There are no plans to remove soft deprecated APIs.

• re.match() and re.Pattern.match() are now soft deprecated in favor of the new re.prefixmatch() and re.Pattern.prefixmatch() APIs, which have been added as alternate, more explicit names. These are intended to be used to alleviate confusion around what match means by following the Zen of Python’s “Explicit is better than implicit” mantra. Most other language regular expression libraries use an API named match to mean what Python has always called search.

  We do not plan to remove the older match() name, as it has been used in code for over 30 years. Code supporting older versions of Python should continue to use match(), while new code should prefer prefixmatch(). See prefixmatch() vs. match().

  (Contributed by Gregory P. Smith in gh-86519 and Hugo van Kemenade in gh-148100.)

• The following typing-related classes are soft deprecated:

  • typing.Optional in favor of the dedicated union syntax (X | None)

  • typing.NoReturn in favor of typing.Never

  • typing.ForwardRef in favor of annotationlib.ForwardRef

  • types.UnionType in favor of typing.Union (but see below)

  Creating typing.Union instances using the constructor is also deprecated. Use the dedicated union syntax (X | Y) instead.

  Explicitly inheriting from typing.Generic is also deprecated. Use the dedicated syntax for generic functions, generic classes, and generic type aliases instead.