fix(upgrade): fallback to --legacy-peer-deps on npm ERESOLVE error during OpenCode plugin upgrades

[decode2]

Summary

Closes #831

Adds automatic fallback to --legacy-peer-deps when an OpenCode plugin upgrade fails due to an npm ERESOLVE peer dependency conflict.

Problem

When running gentle-ai upgrade for OpenCode plugins (such as opencode-sdd-engram-manage or opencode-subagent-statusline), npm 7+ enforces strict peer dependency checks. Upstream peer conflicts (e.g., between @opentui/keymap and @opentui/solid) cause npm install to fail with ERESOLVE could not resolve, leaving the plugin in a failed upgrade state.

Solution

In internal/update/upgrade/strategy.go, when npm returns an execution error during plugin upgrade:

1. Check if the command output contains ERESOLVE or --legacy-peer-deps.
2. Automatically retry the upgrade command with --legacy-peer-deps appended (npm install --save --no-audit --no-fund --legacy-peer-deps ...).
3. Added unit test TestRunStrategyOpenCodePluginNpmERESOLVERetriesWithLegacyPeerDeps in strategy_test.go to verify the retry flow.

Test Plan

• Ran go test ./internal/update/upgrade/... -run TestRunStrategyOpenCodePluginNpmERESOLVERetriesWithLegacyPeerDeps — unit test passes.
• Ran go build ./... — builds cleanly.

Summary by CodeRabbit

• Bug Fixes
  • Improved npm-based package upgrade handling when dependency resolution fails.
  • The updater now detects peer-dependency conflict errors and automatically retries using a compatibility-focused install option to complete more upgrades successfully.
  • Upgrade error messages now include clearer captured command output when retries still fail.
• Tests
  • Added coverage to verify the retry behavior and confirm the retry command arguments.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 344187fc-9f77-4f84-bd6e-6cb224ee56ba

📥 Commits

Reviewing files that changed from the base of the PR and between 1b314f9 and 4c4d1e1.

📒 Files selected for processing (1)

• internal/update/upgrade/strategy.go

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📝 Walkthrough

Walkthrough

opencodePluginUpgrade now captures npm failure output, retries with --legacy-peer-deps for ERESOLVE-related failures, and returns the retry result. A new test verifies the retry path and command arguments.

npm ERESOLVE retry

Layer / File(s)	Summary
ERESOLVE retry logic and test internal/update/upgrade/strategy.go, internal/update/upgrade/strategy_test.go	opencodePluginUpgrade inspects npm failure output, retries with --legacy-peer-deps when ERESOLVE markers are present, and clears the error on success. The test stubs two exec calls, fails the first with an ERESOLVE message, succeeds the second, and asserts the retry includes --legacy-peer-deps.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 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 clearly states the OpenCode upgrade fallback to --legacy-peer-deps on npm ERESOLVE errors.
Linked Issues check	✅ Passed	The change retries OpenCode plugin upgrades on npm ERESOLVE with --legacy-peer-deps, matching #831.
Out of Scope Changes check	✅ Passed	The diff stays focused on the upgrade strategy and its test, with no obvious unrelated changes.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@internal/update/upgrade/strategy.go`:
- Around line 154-159: The npm retry path in strategy.go can still start after
the caller has already cancelled the operation. Re-check ctx with a ctx.Done()
guard immediately before constructing and launching the fallback install in the
npm/ERESOLVE branch inside the upgrade strategy logic, so the retry path exits
early instead of continuing work after cancellation.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 39bbc4e7-753c-4d96-89f8-0c49bfdd0c35

📥 Commits

Reviewing files that changed from the base of the PR and between 8df34cd and 1b314f9.

📒 Files selected for processing (2)

• internal/update/upgrade/strategy.go
• internal/update/upgrade/strategy_test.go