fix(preflight): detect stopped Docker daemon via exit code on macOS

[jyanimaulik]

Summary

Fixes #2348

Problem

assessHost() ran 'docker info --format {{json .}}' with ignoreError:true and treated non-empty stdout as proof the daemon was running. On macOS with Colima stopped, the Docker CLI still emits a client-side JSON struct without contacting the daemon, causing dockerRunning=true incorrectly. Onboarding then passed preflight [1/8] with a false positive and hung indefinitely at [2/8] waiting for gateway health.

Fix

Attempt 'docker info' with ignoreError:false first. If the daemon is unreachable it throws — caught and dockerInfoOutput set to empty string so dockerReachable and dockerRunning remain false. Only on success follow up with the --format call for structured JSON output.

Testing

• 2044 tests pass, 0 new failures introduced
• 1 pre-existing failure (ssrf-parity.test.ts) requires npm run build inside nemoclaw/ — unrelated to this change
• Verified on macOS Apple Silicon M3 Pro with Docker Desktop stopped and running

Summary by CodeRabbit

• Bug Fixes
  • Improved Docker detection during startup validation to avoid false positives when Docker is unreachable, resulting in more reliable readiness checks and clearer handling of Docker detection failures.

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[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between d784c8d and 5568bfc.

📒 Files selected for processing (1)

• src/lib/preflight.ts

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📝 Walkthrough

Walkthrough

The Docker reachability detection in assessHost now runs docker info once without suppressing errors to verify the exit code, and only on success runs the JSON-formatted docker info with error suppression. If the initial call fails, dockerInfoOutput is set to an empty string to avoid false-positive detection.

Changes

Cohort / File(s)	Summary
Docker Reachability Detection src/lib/preflight.ts	Changed assessHost to first run docker info without ignoring errors to check its exit status, then only on success perform the JSON docker info --format '{{json .}}' capture with errors suppressed. Ensures failed CLI/daemon calls do not produce a non-empty JSON that incorrectly marks Docker as running.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 The daemon dozed, the CLI still spoke,
An empty JSON — a sneaky joke.
I check the exit code, then peek inside,
No more false green where sockets hide,
Hopping on truth, with a carrot-certified poke 🥕

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and specifically describes the main fix: detecting a stopped Docker daemon via exit code on macOS, which directly addresses the root cause identified in issue #2348.
Linked Issues check	✅ Passed	The code changes fully implement the required fix by changing the Docker detection logic to check exit codes first and only use formatted output on success, directly addressing all objectives in #2348.
Out of Scope Changes check	✅ Passed	All changes in src/lib/preflight.ts are directly related to the Docker daemon detection fix described in the linked issue; no out-of-scope modifications detected.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[wscurran]

✨ Thanks for submitting this pull request that proposes a way to fix a bug where the Docker daemon status is incorrectly detected on macOS.

Related open issues:

• #2348 [NemoClaw][macOS][Onboard] Preflight check [1/8] falsely reports "✓ Docker is running" when Colima daemon is stopped

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Related open issues:

• #2348 [NemoClaw][macOS][Onboard] Preflight check [1/8] falsely reports "✓ Docker is running" when Colima daemon is stopped