Summary
When the joined items contain both a variable and a string with a double quote, the fix for static-join-to-f-string (FLY002) will cause a syntax error playground:
PS ~>echo @'
"".join((foo, '"'))
'@ | uvx ruff check --select FLY002 - --fix --unsafe-fixes 2>&1 | rg "syntax error"
error: Fix introduced a syntax error. Reverting all changes.
Version
ruff 0.12.8 (f51a228 2025-08-07)