fix(frontend): keep scrolled-in transaction history across the periodic refresh

[sbpublic]

Motivation

Scroll a native EVM token view back through its history, then wait: after about 30 seconds the list snaps back to the newest page, and scrolling down re-fetches everything again. Reproducible on main.

A regression from #13728, which wired up paging without noticing that the refresh timer takes the same code path.

batchLoadTransactions calls loadEthereumTransactions without updateOnly, so the 30-second WALLET_TIMER_INTERVAL_MILLIS tick runs the full load and ends in ethTransactionsStore.set(...). Since #12193 made the native load incremental, that batch is not the whole history — it is the newest stored page (ten rows) plus anything newer than it. Replacing the token's slot with it discards every older page the user scrolled in.

ERC20 views were unaffected only because their history is still fetched whole, so setting the slot there is a genuine refresh.

Changes

• Prepend the batch instead of setting it. A refresh updates the head and leaves the tail alone. prepend already deduplicates by hash, and on a first load the slot is empty, so it behaves exactly like set did.
• Key the pagination-cursor reset on the list being empty, not on updateOnly. The timer path is not updateOnly, so the cursor was also being rewound to the second page every 30 seconds — the next scroll then re-walked pages already in the store. The comment in fix(frontend): show ETH and EVM transaction history beyond the newest page #13728 claiming the timer was updateOnly was simply wrong.

Only the native path changes. ERC token history is still fetched in full, so its set stays correct — until #13730 makes that path incremental too, at which point it needs the same treatment.

Tests

• eth-transactions.services.spec.ts — a refresh keeps pages already scrolled in (the regression itself), and the cursor is left alone once the list has been built. The pre-existing cursor test for a fresh load still holds. The two sets of rows carry fixed, disjoint hashes rather than the mock's random ones, since the store deduplicates by hash and the exact-length assertion would otherwise rest on them never colliding.
• The updateOnly reload test that asserted the cursor was untouched has been rewritten: it passed for the wrong reason — an empty store, not the reload flag.
• npm run format, npm run lint -- --max-warnings 0, npm run check (0 errors), npm run check:tests (0 errors), 3848 tests pass across tests/eth.

Diagnosed statically from the symptom (30s, ten surviving rows, native-only) and confirmed by the reporter on main; not re-verified in a browser here.

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🤖 Generated with Claude Code — Claude Opus 5 (claude-opus-5)

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to c5c6a6d.

Security Overview

• 🔎 Scanned files: 2 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/00881019-f162-4503-9567-953b0be667d7?scanId=78a1fb6e-7153-48f6-81f3-cfc899e30798&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► src/frontend/src/eth/services/eth-transactions.services.ts       Add hasStoredEthTransactions helper and adjust loadEthTransactions behavior to preserve scroll position and prepend new transactions ► src/frontend/src/tests/eth/services/eth-transactions.services.spec.ts       Update tests to reflect new behavior: keep backend cursor when list built and ensure refresh preserves scrolled pages

[Copilot]

Pull request overview

Fixes a regression in the EVM native-asset transaction history where the periodic refresh (timer tick) replaced the store slot with only the newest incremental batch, discarding older pages the user had already paged in and rewinding the backend pagination cursor.

Changes:

• Native EVM loads now prepend the refreshed batch to preserve already-scrolled history instead of replacing the entire in-memory list.
• Backend pagination cursor reset is now keyed off the list being empty (initial build) rather than the updateOnly flag, preventing timer-driven cursor rewinds.
• Tests updated to cover “refresh preserves paged-in rows” and “cursor remains unchanged once the list is built”.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/frontend/src/tests/eth/services/eth-transactions.services.spec.ts	Updates/extends unit tests to assert that periodic refresh keeps previously paged-in transaction rows and doesn’t rewind the cursor.
src/frontend/src/eth/services/eth-transactions.services.ts	Adjusts native ETH/EVM transaction refresh behavior to prepend incremental batches and avoid resetting the backend pagination cursor once the list is populated.

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