Issue #21456 has been reported by dE (dE Techno). ---------------------------------------- Bug #21456: IO.close does not work in a IO::TimeoutError block. https://bugs.ruby-lang.org/issues/21456 * Author: dE (dE Techno) * Status: Open * ruby -v: ruby 3.2.8 (2025-03-26 revision 13f495dc2c) [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Invoking the close method on an IO object based on popen will forcefully close the process (not sure what signal it sends, it's undocumented), however when you handle a IO::TimeoutError exception (which you can get when you set .timeout), the close method fails to end the process. It's going to block until the process naturally terminates. Sample code (linux based) -- execArg = 'echo testwrite; sleep 10' tofuProcess = IO.popen(execArg, 'r') puts 'executed tofu process.' tofuProcess.timeout=5 begin tofuOut = tofuProcess.read rescue IO::TimeoutError puts 'rescue occured' tofuProcess.close puts 'process closed' end -- https://bugs.ruby-lang.org/