fix: EIP-681 QR scans 404 — recipient guard rejects address@chainId (main hotfix)

[abalinda]

Why

Cherry-pick of the EIP-681 fix from #2427, re-targeted at main as a hotfix (original PR is based on dev and carries unrelated dev history).

Scanning any real-world EIP-681 payment QR (e.g. ethereum:USDC@42161/transfer?address=0x…&uint256=3.44e7) dead-ends on the 404 page. The scanner builds /0x…@42161/34.4USDC correctly and the downstream url parser supports recipient@chain — but couldBeRecipient (the Feb-21 /es/argentina SEO-regression guard) tests the EVM-address regex against the full segment including @42161, fails, and notFound()s.

Repro: Konrad's scan 07-15 13:54 UTC (PostHog qr_scanned, qr_type EIP_681, Crisp session_50bb92f0).

What

Two commits cherry-picked from #2427 (b085d10a, a423b1e1):

• couldBeRecipient: strip the @chain suffix before the address/ENS checks (already stripped for the username check); collapse the dead includes('@') ternary.
• generateMetadata ([...recipient]/page.tsx): wrap parseAmountAndToken in try/catch — the widened guard lets /0x…@chain/<garbage> reach it; now falls back to default metadata instead of 500ing.

Design notes / accepted trade-offs

• /0xADDR@<invalid-chain> now renders a 200 with a clean "Invalid chain" ErrorAlert instead of a hard 404 (@-suffixed inputs never reach PublicProfile). Never-indexable URLs, negligible crawl exposure. Tracked in Recipient route guard duplicates parser rules with no contract test (drift risk) #2428.
• The guard remains a deliberate synchronous superset of the async parser; contract-test follow-up in Recipient route guard duplicates parser rules with no contract test (drift risk) #2428.

Risks / breaking changes

• None cross-repo. Route-guard widening only; chain validation still happens downstream.
• Hotfix to main → back-merge debt main→dev (fix: EIP-681 QR scans 404 — recipient guard rejects address@chainId #2427 covers the dev side).

QA

• New assertions: 0xADDR@42161, percent-encoded %4042161, vitalik.eth@arbitrum accepted; locale-regression guards still pass.
• Local: 177/178 suites green (the one red suite, deferred-link.test.ts, is a worktree env artifact — @capacitor/preferences missing from the symlinked node_modules; untouched by this diff).

Summary by CodeRabbit

• New Features

  • Added support for recipient links that include a chain identifier after an address or ENS name, including encoded separators.

• Bug Fixes

  • Prevented malformed amount or token values in links from breaking page rendering.
  • Default metadata is now generated when link parameters cannot be parsed.

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Project	Deployment	Actions	Updated (UTC)
peanut-wallet	Ready	Preview	Aug 5, 2026 2:51pm

[coderabbitai]

📝 Walkthrough

Walkthrough

Recipient detection now supports address and ENS links with optional chain suffixes. Metadata generation now handles malformed amount or token segments by using default metadata values.

Changes

Recipient link handling

Layer / File(s)	Summary
Chain-suffixed recipient validation src/constants/routes.ts, src/constants/__tests__/routes.test.ts	couldBeRecipient removes optional @chain suffixes before validating addresses, ENS names, and usernames. Tests cover numeric and percent-encoded chain identifiers.
Malformed metadata parsing src/app/[...recipient]/page.tsx	Amount and token parsing now catches invalid segments and generates metadata without those values.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• peanutprotocol/peanut-ui#2114: Modifies the same recipient validation and metadata parsing logic.
• peanutprotocol/peanut-ui#2427: Updates couldBeRecipient and related tests for chain-suffixed EIP-681 links.
• peanutprotocol/peanut-ui#2246: Modifies recipient routing behavior in src/constants/routes.ts.

Suggested reviewers: hugo0

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the EIP-681 QR scan 404 fix caused by recipient validation rejecting address@chainId links.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch hotfix/eip681-address-chain-404-main

---

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[github-actions]

Code-analysis diff

Painscore total: 6346.7 → 6346.94 (+0.24)
Findings: 0 net (+6 new, -6 resolved)

🆕 New findings (6)

• high complexity — src/app/[...recipient]/page.tsx — CC 49, MI 44.51, SLOC 135
• high method-complexity — src/app/[...recipient]/page.tsx:18 — generateMetadata CC 42 SLOC 121
• medium high-mdd — src/app/[...recipient]/page.tsx:18 — generateMetadata: MDD 46.3 (uses across many lines from declarations)
• medium structural-dup — app/[...recipient]/page.tsx:157 — 32 duplicate lines / 107 tokens with app/invite/page.tsx:55
• medium complexity — src/constants/routes.ts — CC 14, MI 61.45, SLOC 46
• low missing-return-type — src/app/[...recipient]/page.tsx:188 — Page: exported fn missing return type annotation

✅ Resolved (6)

• src/app/[...recipient]/page.tsx — CC 49, MI 44.57, SLOC 134
• src/app/[...recipient]/page.tsx:18 — generateMetadata CC 42 SLOC 120
• src/app/[...recipient]/page.tsx:18 — generateMetadata: MDD 44.3 (uses across many lines from declarations)
• app/[...recipient]/page.tsx:153 — 32 duplicate lines / 107 tokens with app/invite/page.tsx:55
• src/constants/routes.ts — CC 15, MI 60.99, SLOC 47
• src/app/[...recipient]/page.tsx:184 — Page: exported fn missing return type annotation

[github-actions]

🧪 UI test report — ✅ all green

Suites

• ✅ unit: 2357 ran, 0 failed, 0 skipped, 39.5s

📊 Coverage (unit)

metric	%
statements	63.0%
branches	46.8%
functions	52.9%
lines	63.4%

⏱ 10 slowest test cases

time	test
4.0s	src/components/Card/share-asset/__tests__/shareAssetLayout.test.ts › never places two stickers in heavy overlap (broad seed sweep)
1.0s	src/utils/__tests__/demo-api.test.ts › isDemoMode() is false when not running under Capacitor
0.5s	src/components/Card/share-asset/__tests__/shareAssetLayout.test.ts › every sticker stays within canvas at any count
0.5s	src/app/actions/__tests__/api-headers.test.ts › should include Content-Type in validateInviteCode
0.3s	src/app/(mobile-ui)/withdraw/__tests__/withdraw-states.test.tsx › Bank withdrawal keeps the $1 minimum for sub-$1 amounts
0.3s	src/app/actions/__tests__/api-headers-extended.test.ts › should not include apiKey in validateInviteCode body
0.3s	src/components/Card/share-asset/__tests__/shareAssetLayout.test.ts › keeps stickers off the username pill (final pass respects the keep-out)
0.2s	src/utils/__tests__/url.utils.test.ts › uses the public BASE_URL in Capacitor, not the localhost WebView origin
0.2s	src/utils/__tests__/demo-balance.test.ts › auto-refills a stored balance that has no timestamp (legacy install)
0.2s	src/utils/__tests__/demo-balance.test.ts › debits and floors at zero

_{📍 Inline annotations are in the **Unit test report** check above. Coverage artifact: `coverage-unit`. Generated by `.github/workflows/tests.yml`.}

[abalinda]

@coderabbitai review

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[Copilot]

Pull request overview

Hotfix to main to prevent EIP-681 QR deep links (e.g. /0x…@42161/<amountToken>) from incorrectly 404’ing due to the catch-all recipient route guard rejecting address@chain-shaped segments, and to make metadata generation resilient to malformed amount/token segments.

Changes:

• Updated couldBeRecipient to validate address@chain / ens@chain by stripping the @chain suffix before applying address/ENS/username checks.
• Added regression tests covering address@chainId, percent-encoded %40<chainId>, and ens@chain.
• Wrapped parseAmountAndToken in generateMetadata with try/catch to avoid 500s on malformed amount segments.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/constants/routes.ts	Adjusts recipient guard to consider only the base recipient when @chain is present.
src/constants/tests/routes.test.ts	Adds assertions to ensure address@chain / ens@chain pass the guard.
src/app/[...recipient]/page.tsx	Prevents metadata generation from throwing on malformed amount/token URL segments.

[kushagrasarathe]

Reviewed via pr-review rulebook: T2, all four checklists pass. Guard widening is bounded (chain validation intact downstream), both throw paths covered (generateMetadata try/catch + SemanticRequestPageWrapper .catch). campaign-maps diff is #2610 riding along pending dev back-merge — benign, BE support confirmed on dev and main. Copilot multiple-@ finding: harmless, garbage @-URLs render the documented error state, not a crash. Known advisory eslint red is pre-existing debt, not worsened by this diff.