fix: transaction history POS

[jakubuid]

Summary

• Fix pagination race conditions by canceling in-flight requests when filter changes
• Include existing data in LoadingMore state to prevent UI flicker and race conditions
• Use Locale.ROOT for ISO 8601 date parsing to avoid locale-specific issues
• Remove tokenSymbol from Transaction model (not returned by API)
• Remove unused TOKEN_ADDRESS_TO_SYMBOL hardcoded mapping

Changes

• POSViewModel: Added transactionLoadingJob to track and cancel in-flight requests
• TransactionHistoryUiState: Changed LoadingMore from object to data class with transactions/stats
• TransactionHistoryScreen: Fixed state access pattern, fixed date locale
• Pos.kt: Removed tokenSymbol field from Transaction
• Mapping.kt: Removed extractTokenSymbol() and token address mapping

Test plan

• Verify transaction history loads correctly
• Verify rapid filter changes don't cause duplicate transactions
• Verify loading more transactions shows spinner without losing existing data
• Verify date formatting works on devices with non-US locales

🤖 Generated with Claude Code

[claude]

Claude finished @jakubuid's task in 1m 18s —— View job

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Code Review Complete

Found 3 issue(s)

Issue 1: Potential race on loadedTransactions mutation

ID: posviewmodel-transactions-mutation-b3f7
File: sample/pos/src/main/kotlin/com/walletconnect/sample/pos/POSViewModel.kt:209
Severity: MEDIUM
Category: code_quality

Context:

• Pattern: Line 209 mutates shared loadedTransactions list after async operation without synchronization
• Risk: If job cancellation occurs between fold block and state mutation, another coroutine could start modifying the same list
• Impact: Could lead to concurrent modification, duplicate transactions, or inconsistent state
• Trigger: Rapid filter changes or pagination while previous request completes

Recommendation: Make loadedTransactions immutable per request:

result.fold(
    onSuccess = { historyResult ->
        val updatedList = if (refresh) {
            historyResult.transactions
        } else {
            loadedTransactions + historyResult.transactions
        }
        loadedTransactions.clear()
        loadedTransactions.addAll(updatedList)
        currentCursor = historyResult.nextCursor
        // ...

Issue 2: Missing CancellationException handling in fold block

ID: posviewmodel-cancellation-propagation-a9e2
File: sample/pos/src/main/kotlin/com/walletconnect/sample/pos/POSViewModel.kt:207-226
Severity: LOW
Category: code_quality

Context:

• Pattern: result.fold() catches all exceptions including CancellationException at line 222
• Risk: If PosClient.getTransactionHistory throws CancellationException during cancellation, fold's onFailure catches it instead of propagating
• Impact: Cancelled jobs may emit Error state instead of silently cancelling, showing false errors to user
• Trigger: Cancelling transactionLoadingJob while network request is in flight

Recommendation: Check for cancellation in onFailure block:

onFailure = { error ->
    if (error is CancellationException) throw error
    _transactionHistoryState.value = TransactionHistoryUiState.Error(
        error.message ?: "Failed to load transactions"
    )
}

Issue 3: Locale.ROOT used for output formatting

ID: transactionhistoryscreen-locale-output-d4c1
File: sample/pos/src/main/kotlin/com/walletconnect/sample/pos/screens/TransactionHistoryScreen.kt:412
Severity: LOW
Category: code_quality

Context:

• Pattern: Line 412 uses SimpleDateFormat("MMM dd, yyyy HH:mm", Locale.getDefault()) for output, but comment at 410 says "Use Locale.ROOT for parsing ISO 8601 dates to avoid locale-specific parsing issues"
• Risk: Comment is misleading - Locale.ROOT is correctly used for input parsing (line 411), but developer may think it applies to output too
• Impact: No functional issue, but comment could confuse future maintainers
• Trigger: Code review or maintenance

Recommendation: Clarify comment:

// Parse ISO 8601 with Locale.ROOT to avoid locale-specific parsing issues
val inputFormat = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.ROOT)
// Format output with user's locale for display
val outputFormat = SimpleDateFormat("MMM dd, yyyy HH:mm", Locale.getDefault())

✅ Positive observations:

• Good use of Job cancellation pattern (line 187)
• LoadingMore state correctly includes existing data to prevent UI flicker
• Proper guard in loadMoreTransactions (line 233)
• CancellationException correctly rethrown in ApiClient (lines 289-290)

[claude]

Claude finished @jakubuid's task in 53s —— View job

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🔄 Incremental Review:

✅ All Previously Reported Issues Resolved

Confirmed fixes:

1. posviewmodel-transactions-mutation-b3f7 → Resolved (POSViewModel.kt:210-217)

   • Now builds list immutably using loadedTransactions + historyResult.transactions before clearing/updating

2. posviewmodel-cancellation-propagation-a9e2 → Resolved (POSViewModel.kt:231)

   • Added if (error is CancellationException) throw error check in onFailure block

3. transactionhistoryscreen-locale-output-d4c1 → Resolved (TransactionHistoryScreen.kt:410-411)

   • Clarified comment to distinguish parsing (Locale.ROOT) from output formatting (Locale.getDefault())

✅ No new issues found in latest commits

Code follows Kotlin conventions, proper coroutine handling, and WalletConnect SDK patterns.

[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.7% Duplication on New Code

See analysis details on SonarQube Cloud