Fix flaky DirSingletonTest GC failures in test_fchdir and test_for_fd#3004
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The Dir created by `Dir.new(Dir.pwd).fileno` was only referenced long enough to read its fileno, so it became collectable immediately. When GC ran between the assert_send_type calls the fd was closed, making the later `Dir.fchdir(fd)` fail with Errno::EBADF. Keep the Dir in a local and close it in ensure. Surfaced on ruby/ruby ZJIT CI with --enable-zjit=dev --zjit-call-threshold=1. https://github.com/ruby/ruby/actions/runs/27735384476/job/82051097840 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
test_for_fd has the same pattern as test_fchdir: the Dir from `Dir.new(Dir.pwd).fileno` is collectable before `Dir.for_fd(fd)` runs, so an ill-timed GC closes the fd and the call fails with Errno::EBADF. Keep the Dir alive in a local and close it in ensure. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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The
Dircreated byDir.new(Dir.pwd).filenointest_fchdirandtest_for_fdwas only referenced long enough to read its fileno, so it became collectable right away. When GC ran before the descriptor was used it got closed, making the laterDir.fchdir(fd)andDir.for_fd(fd)calls fail withErrno::EBADF.This surfaced on
ruby/rubyZJIT CI runningmake test-bundled-gemswith--enable-zjit=dev --zjit-call-threshold=1, where allocation and GC timing shifted enough to expose it. Keep the Dir in a local and close it in ensure so the descriptor stays valid for the whole test.https://github.com/ruby/ruby/actions/runs/27735384476/job/82051097840