Description:
The main, antlr4, package is orphaned and stuck at version 4.8.1 while its Python runtime package has been recently updated to version 4.9.1. The C++ runtime is matched and isn't problematic.

This means that the lexer and parser generation cannot be automated during build-time of any given dependent package (one that is targeting Python), i.e. antlr4 cannot be declared as a make dependency as there might be breakage during runtime (warnings are always issued by the generated "checkVersion" method - both in the lexer as well as the parser), once the dependent package is built and subsequently run.

More info (my post) in the official subreddit - https://www.reddit.com/r/archlinux/comments/l0szby/antlr4_package_versions_mismatched/

This is NOT a problem of a package being outdated but solely a problem of versions being mismatched which is not the case upstream. These packages all come from the same upstream source (they're a part of the same ecosystem, so to speak) and their versions should always be synchronized, imho. They aren't even present in the same repositories - antlr4 is in Extra, runtimes are in Community (also different maintainers, in case of the Python runtime).

Additional info:
* antlr4 4.8.1
* config and/or log files etc.
* link to upstream bug report, if any

Steps to reproduce:
None to speak of, everything is right there in the repositories.