[spicysharkco]

Summary

LogfmtRenderer quotes a value only when it contains a space, = or ". A tab or carriage return is written bare, so {"k": "a\tb", "after": "x"} renders as k=a<TAB>b after=x, and go-logfmt reads that back as k=a, b="" and after=x.

Values containing any character from NUL to space are now quoted, the same range the renderer already rejects in keys. Newline is left out of that check because it is escaped as \n, as before.

Inside the quotes, control characters are escaped as \t, \r or \u00XX rather than written raw. go-logfmt rejects a quoted value that holds a raw control character together with an escape, so a stack trace line such as "Foo\n\tat_bar" would make it drop the rest of the record. go-logfmt's own encoder escapes tab and carriage return the same way. The new rows in test_escaping (a tab, a carriage return, a tab next to a newline, and \x01) fail without the change.

Pull Request Checklist

• I acknowledge this project's AI policy.
• This pull request is not from my main branch.
  • Consider granting push permissions to the PR branch, so maintainers can fix minor issues themselves without pestering you.
• There's tests for all new and changed code.
• New APIs are added to our typing tests in api.py. (n/a, no new APIs)
• Updated documentation for changed code. (n/a, no documented behavior changed)
  • New functions/classes have to be added to docs/api.rst by hand. (n/a)
  • Changed/added classes/methods/functions have appropriate versionadded, versionchanged, or deprecated directives. (n/a)
    • The next version is the second number in the current release + 1. The first number represents the current year. So if the current version on PyPI is 26.1.0, the next version is gonna be 26.2.0. If the next version is the first in the new year, it'll be 27.1.0.
• Documentation in .rst and .md files is written using semantic newlines.
• Changes (and possible deprecations) are documented in the changelog.

[codspeed]

Merging this PR will not alter performance

⚠️ 1 benchmark spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• import structlog

✅ 11 untouched benchmarks

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_{Comparing spicysharkco:fix-logfmt-quote-whitespace (0213389) with main (19c4f21)}