refactor: remove dup fetching position keys

[antoncoding]

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of missing market data from the Morpho API—the system now gracefully returns empty or null results instead of throwing errors
  • Enhanced fallback logic to use Subgraph data only when the Morpho API actually fails
  • Increased resilience to incomplete or missing API responses across multiple data sources

• Style

  • Minor formatting improvements in component styling

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Project	Deployment	Review	Updated (UTC)
monarch	Ready	Preview, Comment	Jan 20, 2026 3:05am

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes add graceful null handling for GraphQL NOT_FOUND errors across the Morpho API data layer. The core fetcher now returns null instead of throwing on NOT_FOUND, and callers guard against falsy responses with early returns or empty defaults. GraphQL response types are relaxed to optional fields.

Changes

Cohort / File(s)	Summary
Core Fetcher src/data-sources/morpho-api/fetchers.ts	Return type changed to Promise<T | null>. Detects NOT_FOUND errors and returns null; preserves throw behavior for other errors.
Market Data Handlers src/data-sources/morpho-api/market.ts, src/data-sources/morpho-api/historical.ts, src/data-sources/morpho-api/market-{borrowers,borrows,liquidations,suppliers,supplies}.ts	Added early returns when fetch result is falsy (null/undefined). GraphQL response types updated to optional fields (data?, items?, pageInfo?). Existing mapping and error paths unchanged.
Other Data Handlers src/data-sources/morpho-api/positions.ts, src/data-sources/morpho-api/prices.ts, src/data-sources/morpho-api/transactions.ts, src/data-sources/morpho-api/{v2-vaults,vaults}.ts	Added guards for falsy responses, returning empty arrays or null before processing. Made response types optional. Error re-throw behavior refined in positions.ts.
Hook Logic src/hooks/useUserPositions.ts	Added apiError flag; fallback to Subgraph now only triggers when Morpho API is attempted AND returns no markets AND errors.
UI Refactor src/features/positions/components/supplied-markets-detail.tsx	Collapsed multi-line conditional ternaries into single-line expressions. No logic changes.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• refactor: add backup data source  #140: Modifies morphoGraphqlFetcher and its call sites to return null on NOT_FOUND errors instead of throwing.
• feat: vault page fixes and collateral #169: Handles GraphQL NOT_FOUND in v2-vaults.ts by returning null rather than throwing.
• feat: Add 'Supply' Button to Position Page #77: Restructures useUserPositions.ts with GraphQL query imports and data shape changes.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Title check	⚠️ Warning	Title mentions 'remove dup fetching position keys' but changes span Morpho API response handling across 13+ files, making it incomplete relative to the actual scope.	Title should reflect the main change: handling missing/NOT_FOUND API responses gracefully. Consider: 'refactor: handle NOT_FOUND responses in Morpho API fetchers' or similar.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/vault-read

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[coderabbitai]

Actionable comments posted: 1

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/hooks/useUserPositions.ts (1)

64-89: Logic bug: Subgraph fallback broken for non-Morpho-API networks.

When supportsMorphoApi(network) is false, the code skips the Morpho block entirely. apiError stays false and markets stays []. The condition on line 79 (markets.length === 0 && apiError) is never true, so Subgraph is never called.

The previous behavior likely fell back to Subgraph when markets.length === 0 regardless of error state.

Proposed fix

       // If Morpho API failed or not supported, try Subgraph
-      if (markets.length === 0 && apiError) {
+      if (markets.length === 0 && (apiError || !supportsMorphoApi(network))) {
         try {
           console.log(`Attempting to fetch positions via Subgraph for network ${network}`);
           markets = await fetchSubgraphUserPositionMarkets(user, network);

🤖 Fix all issues with AI agents

In `@src/data-sources/morpho-api/fetchers.ts`:
- Around line 23-29: The NOT_FOUND check currently inspects err.status which
doesn't exist, so update the guard to examine the message field instead: in the
notFoundError computation (the variable named notFoundError that iterates
(result as any).errors), change the predicate to check
err.message?.includes('NOT_FOUND') (and adjust the inline type from { status?:
string } to { message?: string } if present) so the branch that logs "Morpho API
return Not Found error" and returns null will correctly trigger for NOT_FOUND
errors.

🧹 Nitpick comments (1)

src/data-sources/morpho-api/vaults.ts (1)

34-41: Type updated, but errors field no longer checked.

The errors field is still in the type (line 40) but no longer checked in the function. This is fine since the fetcher now handles GraphQL errors centrally, though you could remove errors from the type for clarity.