[mithilkatkoria]

With group: true, output from later commands can be lost when a middle command fails to spawn before the first command finishes. For example, run a slow command, a command with a nonexistent cwd, and a command that immediately prints a message. The final message remains buffered even after all processes finish.

Command preserves its errored state after the close event. Treat that state as finished when advancing grouped output, just as for exited. The regression verifies ordered flushing of both the spawn error and the later command's output, with no remaining buffered text.

Validation:

• Reproduced the missing output through the built API with real child processes before the fix; the same reproduction now prints the message and passes an assertion.
• The new unit regression fails before the fix. Output-writer, command, and core concurrently tests pass (67 tests).
• Full CI test command with coverage: 647 tests pass, including all four smoke tests. One unrelated SIGINT test cannot start on this Windows ARM64 host because ctrlc-wrapper@0.0.5 only maps x64 and ia32, producing Cannot find module 'ctrlc-wrapper-windows-undefined/start.exe' before application execution.
• Repository lint, typecheck, formatting, build, diff check, and the actual lint-staged pre-commit hook pass. No dependency or lockfile changes.

AI disclosure: OpenAI Codex (GPT-6) found and reproduced the bug, implemented the patch and regression, performed the self-review, ran the reported checks, and wrote this description. No independent human review is claimed.

[coveralls]

coverage: 98.768% (+0.002%) from 98.766% — mithilkatkoria:fix/grouped-output-spawn-error into open-cli-tools:main

[gustavohenke]

Makes sense, thanks Codex