refactor(preflight): simplify swap handling

[cv]

Summary

Refactor bin/lib/preflight.js swap handling to satisfy the current ESLint rules. This keeps the existing behavior but reduces ensureSwap() complexity and replaces the empty catch block with an explicit best-effort path.

Changes

• extract swapfile existence, existing swap activation, disk-space checks, marker writing, cleanup, and creation into small helpers
• simplify ensureSwap() control flow so it stays under the configured complexity limit
• replace the empty catch around the managed swap marker write with a documented best-effort catch

Type of Change

• Code change for a new feature, bug fix, or refactor.
• Code change with doc updates.
• Doc only. Prose changes without code sample modifications.
• Doc only. Includes code sample changes.

Testing

• npx prek run --all-files passes (or equivalently make check).
• npm test passes.
• make docs builds without warnings. (for doc-only changes)

Ran locally:

• npm run lint
• npm test -- test/preflight.test.js
• npm test (currently fails locally in existing test/onboard.test.js cases unrelated to this change)

Checklist

General

• I have read and followed the contributing guide.
• I have read and followed the style guide. (for doc-only changes)

Code Changes

• Formatters applied — npx prek run --all-files auto-fixes formatting (or make format for targeted runs).
• Tests added or updated for new or changed behavior.
• No secrets, API keys, or credentials committed.
• Doc pages updated for any user-facing behavior changes (new commands, changed defaults, new features, bug fixes that contradict existing docs).

Summary by CodeRabbit

• Refactor
  • Reorganized internal swap provisioning to improve maintainability and reliability with no change to user-facing behavior.
• Tests
  • Extended sandbox health-check mocks so provisioning/startup flows are more reliably validated in automated tests.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 059be4b4-76cf-48c2-8f5b-cebc6d432f73

📥 Commits

Reviewing files that changed from the base of the PR and between 81423f8 and 5d08a35.

📒 Files selected for processing (1)

• test/onboard.test.js

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📝 Walkthrough

Walkthrough

Refactored swap provisioning in bin/lib/preflight.js by extracting inline logic from ensureSwap() into helper functions (getExistingSwapResult, checkSwapDiskSpace, createSwapfile, cleanupPartialSwap, writeManagedSwapMarker) and adjusting control flow (including dry-run early return).

Changes

Cohort / File(s)	Summary
Swap Provisioning Refactor bin/lib/preflight.js	Extracted swap-related helpers for existing-swap detection, disk-space guard, swapfile creation, cleanup, and managed-marker persistence. Replaced inline blocks with helper calls, removed redundant platform local, and tightened memory-info retrieval.
Test: sandbox health probe test/onboard.test.js	Added mocks for an in-sandbox health-check command (sandbox exec ... curl -sf http://localhost:18789/) in two runner.runCapture stubs so the probe returns "ok" for affected flows.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Poem

🐰 I hopped through heaps of code tonight,
Extracted bits and set them right,
Helpers snug in tidy rows,
Swapfile springs where memory grows,
🍃 A small hop, and tests say “ok” — delight!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and concisely describes the main change: refactoring swap handling in the preflight module to simplify code organization.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

bin/lib/preflight.js (1)

228-239: Prefer fs.mkdirSync over shell mkdir -p.

Using a shell command for directory creation is unnecessary when Node.js provides fs.mkdirSync with recursive: true. This also avoids a potential command injection risk if os.homedir() contains shell metacharacters (unlikely but possible).

♻️ Suggested refactor

 function writeManagedSwapMarker() {
   const nemoclawDir = path.join(os.homedir(), ".nemoclaw");
-  if (!fs.existsSync(nemoclawDir)) {
-    runCapture(`mkdir -p ${nemoclawDir}`, { ignoreError: true });
-  }
+  fs.mkdirSync(nemoclawDir, { recursive: true });
 
   try {
     fs.writeFileSync(path.join(nemoclawDir, "managed_swap"), "/swapfile");

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@bin/lib/preflight.js` around lines 228 - 239, The writeManagedSwapMarker
function currently uses runCapture("mkdir -p ...") to create the .nemoclaw
directory; replace that shell call with Node's fs.mkdirSync(nemoclawDir, {
recursive: true }) to avoid spawning a shell and potential injection risks and
to use native filesystem behavior; keep the existing existence check or simply
call mkdirSync in a try/catch and preserve the current best-effort semantics
(the try/catch around fs.writeFileSync for the managed_swap marker should remain
unchanged).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@bin/lib/preflight.js`:
- Around line 228-239: The writeManagedSwapMarker function currently uses
runCapture("mkdir -p ...") to create the .nemoclaw directory; replace that shell
call with Node's fs.mkdirSync(nemoclawDir, { recursive: true }) to avoid
spawning a shell and potential injection risks and to use native filesystem
behavior; keep the existing existence check or simply call mkdirSync in a
try/catch and preserve the current best-effort semantics (the try/catch around
fs.writeFileSync for the managed_swap marker should remain unchanged).

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: b732a5d4-367d-4f97-a595-c13710db1c1b

📥 Commits

Reviewing files that changed from the base of the PR and between 711b98e and 81423f8.

📒 Files selected for processing (1)

• bin/lib/preflight.js

[ericksoa]

Clean refactoring — the extracted helpers make ensureSwap() much easier to follow. Behavior-preserving with good early-return structure for the dry-run path. LGTM.