fix(AI-CLI-if5u): resolve real tty device before backgrounding agent stdin - #147
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sergeiwallace merged 1 commit intoSep 15, 2026
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…stdin commit 6f0127b redirected a backgrounded agent's stdin from the literal /dev/tty alias. On macOS, kqueue refuses to poll an fd opened through that alias path (ttyname_r resolves it to /dev/tty again rather than a real device) -- Bun-compiled claude then crashes with EINVAL on launch. Resolve the controlling terminal's actual device path via `tty` first and redirect from that instead, falling back to the literal /dev/tty when resolution fails. Root cause corroborated externally: oven-sh/bun#41504. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PFi83LbqMTznL3DW2sVm9d
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Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PFi83LbqMTznL3DW2sVm9d
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Summary
ai c 1failed to launch/resume a CC session on macOS: Claude Code (Bun-compiled) crashed withEINVAL: invalid argument, kqueueafter commit 6f0127b (fix(AI-CLI-1rk1): retain pi's terminal stdin when backgrounded, add consecutive-failure circuit breaker #145) started redirecting a backgrounded agent's stdin from the literal/dev/ttyalias./dev/ttyalias path (ttyname_rresolves it back to/dev/ttyitself rather than a real device). Externally confirmed: oven-sh/bun#41504.ttybefore backgrounding, and redirect from that resolved path. Falls back to the literal/dev/ttywhen resolution fails, same as before.Test plan
test_given_terminal_stdin_when_agent_is_backgrounded_then_resolved_device_path_is_preferredadded, confirmed RED on unfixed code, GREEN after the fix.ruff check/ruff format --checkpass.tests/test_session_launch_shell_resolution.py): 11 passed.test_public_repo_hygiene.py,test_native_deps.py,test_session_reload_mtime.py,test_stale_session_reaper.py[zsh]) are pre-existing/environmental — reproduced identically on the pre-fix commit, unrelated to this change (the[zsh]supervisor failures trace to this worktree's unapproved.envrc, tracked separately as AI-CLI-np2i).ai c 1re-launch on the real host to close the loop (orchestrator/user follow-up, not verifiable in this sandbox).docs/bugs/ai-cli-if5u-kqueue-dev-tty-einval.md has the full root-cause writeup.