Removal of parser.set_application breaks parser

[jgrey4296]

Describe the bug

PR #13644 and PR #13637 break my bibtex parser, as uses the set_application hook to get config values.
What is the preferred way of getting sphinx config values an extension registers, from a parser?
The docs still say to use set_application, .config and .env, all of which are deprecated.

How to Reproduce

Minimal reproduction would be to use a parser that accesses set_application, like sphinx_bib_domain and try to parse a .bib file.

Environment Information

Platform:              linux; (Linux-6.17.0-20-generic-x86_64-with-glibc2.39)
Python version:        3.12.3 (main, Mar  3 2026, 12:15:18) [GCC 13.3.0])
Python implementation: CPython
Sphinx version:        9.1.0
Docutils version:      0.21.2
Jinja2 version:        3.1.6
Pygments version:      2.19.2

Sphinx extensions

["sphinx_bib_domain"]

Additional context

No response

[FazeelUsmani]

Hi @jgrey4296 — #14372 un-deprecates Parser.config and Parser.env so they remain the supported way to read config/env from a custom parser. set_application itself stays deprecated, but for your sphinx_bib_domain use case the migration should just be dropping the set_application override and reading self.config / self.env directly inside parse(). Let me know if that works for you.

[jgrey4296]

Thanks, and I'm using that pull-request writeup as my personal best practice example from now on.