Issue #20743 has been updated by x-yuri (Yuri Kanivetsky). Apparently introduced in the following commit: https://github.com/ruby/ruby/commit/5a4f997b2e8e819ed40731cd769826112072a9d4... ---------------------------------------- Bug #20743: ruby doesn't properly split RUBY_DEBUG_LOG_FILTER into items https://bugs.ruby-lang.org/issues/20743#change-109785 * Author: x-yuri (Yuri Kanivetsky) * Status: Open * ruby -v: ruby 3.4.0dev (2024-09-15T01:06:11Z master 532af89e3b) +PRISM [x86_64-linux-musl] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- ``` $ docker run --rm alpine:3.20.3 sh -euxc ' apk add git build-base autoconf ruby yaml-dev zlib-dev openssl-dev libffi-dev git clone https://github.com/ruby/ruby cd ruby git checkout 532af89e3b5b78dd3a6fe29c6cc64ad1b073afe2 ./autogen.sh ./configure cflags=-DUSE_RUBY_DEBUG_LOG --disable-install-doc make -j8 install ruby -v RUBY_DEBUG_LOG=stderr RUBY_DEBUG_LOG_FILTER=rb_thread_schedule_limits,rb_ractor_thread_switch ruby -e "" ' ... + RUBY_DEBUG_LOG=stderr RUBY_DEBUG_LOG_FILTER=rb_thread_schedule_limits,rb_ractor_thread_switch ruby -e RUBY_DEBUG_LOG=stderr [stderr] RUBY_DEBUG_LOG_FILTER[0]=rb_thread_schedule_limit (all) RUBY_DEBUG_LOG_FILTER[1]=rb_ractor_thread_switch (all) ... ``` As you can see `ruby` reports that `RUBY_DEBUG_LOG_FILTER[0]` equals `rb_thread_schedule_limit`, not `rb_thread_schedule_limits`. This happens because here: https://github.com/ruby/ruby/blob/532af89e3b5b78dd3a6fe29c6cc64ad1b073afe2/d... `1` should not be subtracted. Also in the following lines `str` is increased, but `len` is not decreased. It makes sense to recheck if there are no further mistakes. -- https://bugs.ruby-lang.org/