Issue #20231 has been updated by naruse (Yui NARUSE). Backport changed from 3.2: REQUIRED, 3.3: REQUIRED to 3.2: REQUIRED, 3.3: DONE ruby_3_3 2c365e6dfb95e0df24725c6f377b9cdf5e354557 merged revision(s) 2554c5d3b8738a248cedb2fea96dfab9fbe19417. ---------------------------------------- Bug #20231: Don't wait in io_binwrite_string if not necessary. https://bugs.ruby-lang.org/issues/20231#change-106600 * Author: ioquatix (Samuel Williams) * Status: Closed * Priority: Normal * Assignee: ioquatix (Samuel Williams) * Backport: 3.2: REQUIRED, 3.3: DONE ---------------------------------------- PR: https://github.com/ruby/ruby/pull/9792 Writing to a buffered IO can result in the entire internal buffer being flushed, which causes `io_binwrite_string_internal` to return 0. In that case, we were setting `errno = EAGAIN`. This causes `rb_io_maybe_wait_writable` to be invoked, however we should immediately retry `io_binwrite_string_internal` instead. The reason why calling `rb_io_maybe_wait_writable` is a bad idea in general, is that not all IO can go via this mechanism in every situation - in other words, `kqueue` does not support `kevent("/dev/null", writable)` and returns errno=22 `EINVAL`. The same applies to some kinds of pipes, TTYs, etc. Indirectly responsible for <https://github.com/socketry/async/issues/301>. -- https://bugs.ruby-lang.org/