fix(engine): stop parseAmsPolicySpec aliasing the frozen DEFAULT_AMS_POLICY_SPEC sub-objects

[RealDiligent]

Summary

DEFAULT_AMS_POLICY_SPEC (packages/loopover-engine/src/ams-policy-spec.ts) is a deep-frozen shared singleton, and its own doc says "clone before layering overrides on top." But normalizeCapLimits and normalizeConvergenceThresholds returned their fallback — which parseAmsPolicySpec passes as DEFAULT_AMS_POLICY_SPEC.capLimits / .convergenceThresholds — by reference on the undefined/null and not-a-mapping paths (only the valid-mapping path built a fresh object).

So a parsed spec that carries at least one configured field (and therefore returns the normalized spec at line 389, not the all-defaults cloneDefaultAmsPolicySpec() at line 387) aliased the frozen singleton's sub-objects into a caller's mutable spec — the exact hazard the singleton's doc warns about.

Fix

Return { ...fallback } on both fallback paths of each normalizer (a shallow copy fully de-aliases since every field is a primitive), mirroring how normalizeNetworkAllowlist / normalizeEcosystemList already copy their fallback on every return path. No production values change; DEFAULT_AMS_POLICY_SPEC and its sub-objects stay frozen.

Tests

Added to packages/loopover-engine/test/ams-policy-spec-parser.test.ts:

• Parsed capLimits/convergenceThresholds are deepEqual to the defaults but notStrictEqual (distinct objects), are not frozen, and mutating them cannot corrupt DEFAULT_AMS_POLICY_SPEC.
• The not-a-mapping paths ({ capLimits: "nope", convergenceThresholds: [] }, and the configured-field variant that actually returns the normalized spec) also yield fresh, non-aliased copies.
• DEFAULT_AMS_POLICY_SPEC and all three of its sub-objects remain Object.isFrozen.

The two regression tests fail against the current by-reference code; the existing value assertions pass unchanged. Engine-flag coverage of the four changed lines verified (source-mapped lcov).

Closes #9995

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[loopover-orb]

Tip

✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-31 06:33:04 UTC}

2 files · 1 AI reviewer · no blockers · readiness 98/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
Fixes a real aliasing bug: normalizeCapLimits and normalizeConvergenceThresholds previously returned the frozen DEFAULT_AMS_POLICY_SPEC sub-objects by reference on the undefined/null and not-a-mapping paths, while only the valid-mapping path built a fresh object. The shallow `{ ...fallback }` copy is correct since both AmsCapLimits and PortfolioConvergenceThresholds are flat primitive-only shapes, and this mirrors the existing pattern already used in normalizeNetworkAllowlist/normalizeEcosystemList/normalizeExtraHosts in the same file. Tests directly exercise both fallback branches (undefined/null and not-a-mapping) plus the previously-untested case where a configured sibling field routes through the not-a-mapping fallback into the returned (non-default) spec, and assert frozen-state is preserved on the singleton.

Nits — 2 non-blocking

• The new inline comments in normalizeCapLimits/normalizeConvergenceThresholds are a bit verbose for a one-line fix; a shorter note like the existing normalizeEcosystemList comment would keep style consistent (ams-policy-spec.ts:211-213, :232-233).
• Consider trimming the two new multi-line comments to a single line to match the terser style of the comment above normalizeNetworkAllowlist's fallback returns.

Decision drivers

• ✅ Code review — No blockers (1 reviewer)
• ✅ Gate result — Passing (No configured blocker found.)

Context & advisory signals — never blocks the verdict

Signal	Result	Evidence
Linked issue	✅ Linked	#9995
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	✅ 25/25	PR body includes validation/test evidence.
Contributor workload	✅ 10/10	Author activity: 242 registered-repo PR(s), 94 merged, 38 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	RealDiligent; Gittensor profile; 242 PR(s), 38 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The diff makes both normalizeCapLimits and normalizeConvergenceThresholds return fresh shallow copies on all fallback paths (undefined/null and not-a-mapping), matching the exact pattern used by normalizeEcosystemList/normalizeNetworkAllowlist as required, and adds regression tests verifying values are unchanged, objects are non-aliased/unfrozen, and DEFAULT_AMS_POLICY_SPEC remains frozen.

Review context

• Author: RealDiligent
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: not available
• Official Gittensor activity: 242 PR(s), 38 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Keep the PR focused and include validation evidence before maintainer review.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

🧪 Chat with LoopOver

Ask LoopOver a question about this PR directly in a comment — grounded only in the same cached, public-safe facts shown above, never a new claim.

• @loopover ask <question> answers contribution-quality Q&A with source citations and freshness.
• @loopover chat <question> answers in natural prose from cached decision-pack facts via local inference (maintainer/collaborator; read-only).
• A plain-language @loopover mention with a real question is routed to the closest matching read-only command automatically — no exact syntax required.

Full command reference: https://loopover.ai/docs/loopover-commands

🧪 Experimental — new and may change.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

---

💰 Earn for open-source contributions like this. Gittensor lets GitHub contributors earn for the work they already do — register to start earning →.

Checked by LoopOver, a quiet PR intelligence layer for OSS maintainers.

• Re-run LoopOver review

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.88%. Comparing base (a7673e2) to head (f116abf).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10069      +/-   ##
==========================================
- Coverage   91.88%   91.88%   -0.01%     
==========================================
  Files         930      930              
  Lines      113827   113832       +5     
  Branches    27466    27466              
==========================================
+ Hits       104588   104589       +1     
  Misses       7940     7940              
- Partials     1299     1303       +4     

Flag	Coverage Δ
backend	95.66% <100.00%> (-0.01%)	⬇️
engine	72.35% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
packages/loopover-engine/src/ams-policy-spec.ts	98.12% <100.00%> (+0.02%)	⬆️

... and 1 file with indirect coverage changes

[loopover-orb]

LoopOver approves — the gate is satisfied and CI is green.