fix(exit): silence virtual exit statuses and allow exit 0 under errexit

[konard]

Caught virtual exit 7 failures previously populated stderr with Command failed with exit code 7 and mirrored that text to the parent process. Under set('e'), even exit 0 rejected. This change makes both statuses silent and lets successful exits resolve.

Fixes #213.

Changes

• Throw only for nonzero statuses, with explicit empty stderr. The runner retains the existing status aliases and decides whether to reject according to errexit.
• Remove the exit handler's dependency on global shell settings.
• Preserve sequence stopping after a failing exit under errexit, including when capture is disabled; unexpected virtual-handler failures still report their diagnostic stderr.
• Add eight regression tests to the existing Bun suite and Node 22/24/26 CI jobs.
• Add a reusable reproduction and a patch changeset for the next npm release.

Reproduction and regression coverage

node experiments/issue-213/virtual-exit.mjs 2>stderr.txt
bun experiments/issue-213/virtual-exit.mjs 2>stderr.txt
node --test js/tests/virtual-exit.test.mjs
bun test js/tests/virtual-exit.test.mjs --timeout 10000

Before implementation, six of eight tests failed under both runtimes. The nine-case probe showed bogus stderr for caught nonzero exits and rejected status 0 under errexit. After the fix, all observations have empty stderr and stderr.txt is empty. exit 7 rejects under errexit, while exit 0 and argumentless exit resolve. A real child process provides the silent-status comparison.

Tests also verify result/error status aliases, output and exit events, stopping a sequence after exit 3, default mirroring, disabled mirroring/capture, non-errexit results, and unexpected-handler diagnostics.

Validation

• Focused Bun suite: 61 passed; Node exit regression suite: 8 passed.
• Existing Node regression suites plus the new exit tests: 104 passed.
• bun run check: ESLint, repository formatting, duplication, and TypeScript declarations passed.
• Documentation/workflow regression checks: 386 passed.
• All 29 executable features agree under Node and Bun and run in Rust.
• Full Bun suite: 2,574 passed, 10 skipped, 0 failed across 153 files.
• Full Rust suite, including doc tests: 830 passed, 5 ignored, 0 failed.
• Node zx compatibility: 490 passed, 2 skipped; Execa compatibility: 38 passed.
• Generated documentation and changeset/version validation passed.
• All seven CI workflows pass on f9f55a0, including Bun on Linux/macOS/Windows, Node 22/24/26, process-tree checks, security, quality, dependency freshness, executable parity, and benchmark smoke checks: JavaScript checks.

The first macOS Node 24 process-tree job observed one extra heartbeat byte (6 !== 5) in the existing exec: stubborn test at js/tests/windows-tree-kill.test.mjs:87 (preserved run log, line 1806). Its 19 tests passed on a single rerun of the same commit: successful rerun. The initial failure and rerun logs are preserved in ci-logs/. The new exit regressions passed in every runtime job on the first attempt.

Scope and release

This is JavaScript-specific and carries parity-exempt: Rust's exit handler already returns the requested code with empty stderr. Executable language parity remains enabled. Existing argument parsing and non-errexit sequence behavior are preserved; full POSIX shell termination semantics are outside this issue's fix.

js/.changeset/issue-213-virtual-exit.md prepares the next patch release. Package versions remain managed by the release workflow.

Changes

• 7 file(s) modified
• 233 line(s) added
• 3 line(s) removed
• Files:
  • .github/workflows/js.yml
  • experiments/issue-213/README.md
  • experiments/issue-213/virtual-exit.mjs
  • js/.changeset/issue-213-virtual-exit.md
  • js/src/$.mjs
  • js/src/commands/$.exit.mjs
  • js/tests/virtual-exit.test.mjs

[konard]

Working session summary

Fixed both virtual exit bugs, added regression tests and a patch changeset, and marked PR #215 ready for review.

Validation: 2,574 Bun tests and 830 Rust tests passed. All seven CI workflows pass after one existing macOS timing test passed on rerun. The working tree is clean.

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[konard]

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[konard]

🎉 Auto-merged

This pull request has been automatically merged by hive-mind.

• All CI checks have passed

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Auto-merged by hive-mind with --auto-merge flag