Log refactor formatter

[semohr]

This pull request refactors how log messages are formatted in the codebase, specifically replacing the use of a logging filter with a custom logging formatter to append plugin names to log messages. This change improves flexibility and future extensibility for logging setups.

This is part of the multi-step efforts to improve logging in beets #6553

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This change should yield no visible change for users and is entirely a internal refactor:

musicbrainz: Searching for '' with {'release': 'somebody that i used to know', 'arid': '89ad4ac3-39f7-470e-963a-56509c546377'}
Searching for MusicBrainz releases with: 'release:(somebody that i used to know) arid:(89ad4ac3\\-39f7\\-470e\\-963a\\-56509c546377)'
musicbrainz: Found 5 result(s)
musicbrainz: Requesting MusicBrainz release 7841a24b-02fc-437e-a146-e59de916f1a2

[codecov]

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RuntimeError: Error converting computed name to ValidatedString
Caused by:
    string is too long</code></pre>

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[Copilot]

Pull request overview

PR move plugin-name prefixing in logs from logging.Filter into custom logging.Formatter, so logging setup can grow into future config-driven format.

Changes:

• Remove PluginLogFilter from plugin logger setup.
• Add LegacyFormatter and set it on default beets UI stream handler to build musicbrainz: msg style output.
• Note internal refactor in changelog.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
docs/changelog.rst	Document switch from filter-based to formatter-based plugin prefixing.
beets/ui/init.py	Default beets logger handler now uses LegacyFormatter("%(legacy_msg)s").
beets/plugins.py	Stop attaching per-plugin PluginLogFilter to plugin child loggers.
beets/logging.py	Introduce LegacyFormatter that builds legacy_msg from child logger name + message.

[semohr]

Current test failures are expected as the caplog setup we use currently in testing does not capture the formatting correctly.

[snejus]

Current test failures are expected as the caplog setup we use currently in testing does not capture the formatting correctly.

I guess you want to rebase this on the branch that fixes the caplog setup?

[semohr]

I guess you want to rebase this on the branch that fixes the caplog setup?

Yeah that was my idea. I did not want to fixup the capture_log contextmanager to just remove it again two PRs down the line.