fix(stability): close crash paths found in the 2026-08 crash audit

DashWallet/Sources/Application/Syncyng Activity Monitor/SyncingActivityMonitor.swift

@@ -136,7 +136,7 @@ class SyncingActivityMonitor: NSObject, NetworkReachabilityHandling {
     @objc
     public var progress: Double = 0 {
         didSet {
-            observers.forEach { $0.syncingActivityMonitorProgressDidChange(progress) }
+            observerSnapshot().forEach { $0.syncingActivityMonitorProgressDidChange(progress) }
         }
     }
 
@@ -157,7 +157,7 @@ class SyncingActivityMonitor: NSObject, NetworkReachabilityHandling {
                                                 kSyncStateChangedNewStateKey: state,
                                             ])
 
-            observers.forEach { $0.syncingActivityMonitorStateDidChange(previousState: oldValue, state: state) }
+            observerSnapshot().forEach { $0.syncingActivityMonitorStateDidChange(previousState: oldValue, state: state) }
         }
     }
 
@@ -178,7 +178,8 @@ class SyncingActivityMonitor: NSObject, NetworkReachabilityHandling {
     private var lastPeakDate: Date?
     private var cancellables = Set<AnyCancellable>()
 
-    private lazy var observers: [SyncingActivityMonitorObserver] = []
+    private var observers: [SyncingActivityMonitorObserver] = []
+    private let observersLock = NSLock()
 
     override init() {
         super.init()
@@ -196,19 +197,32 @@ class SyncingActivityMonitor: NSObject, NetworkReachabilityHandling {
 
     @objc(addObserver:)
     public func add(observer: SyncingActivityMonitorObserver) {
+        observersLock.lock()
+        defer { observersLock.unlock() }
         observers.append(observer)
     }
 
     @objc(removeObserver:)
     public func remove(observer: SyncingActivityMonitorObserver) {
+        observersLock.lock()
+        defer { observersLock.unlock() }
         if let idx = observers.firstIndex(where: { $0 === observer }) {
             observers.remove(at: idx)
         }
     }
 
+    private func observerSnapshot() -> [SyncingActivityMonitorObserver] {
+        observersLock.lock()
+        defer { observersLock.unlock() }
+        return observers
+    }
+
     deinit {
         NotificationCenter.default.removeObserver(self)
-        NotificationCenter.default.removeObserver(reachabilityObserver!)
+        if let observer = reachabilityObserver {
+            NotificationCenter.default.removeObserver(observer)
+            reachabilityObserver = nil
+        }
     }
 
     /// ObjC-visible accessor for `.syncStateChangedNotification` (same

DashWallet/Sources/Categories/NumberFormatter+DashWallet.swift

@@ -44,27 +44,25 @@ extension NumberFormatter {
             return formattedString
         }
 
-        var currencySymbolRange: Range<String.Index>! = formattedString.range(of: currencySymbol)
+        var currencySymbolRange = formattedString.range(of: currencySymbol)
 
         if currencySymbolRange == nil && currencySymbol.count != numberFormatter.currencySymbol.count {
-            assertionFailure("Invalid formatted string")
+            return nil
         } else if currencySymbolRange == nil {
             currencySymbolRange = formattedString.range(of: numberFormatter.currencySymbol)
         }
 
         guard let currencySymbolRange else {
-            fatalError("Invalid formatted string")
+            return nil
         }
 
         let isCurrencySymbolAtTheBeginning = currencySymbolRange.lowerBound == formattedString.startIndex
         var currencySymbolNumberSeparator: String
 
         if isCurrencySymbolAtTheBeginning {
-            currencySymbolNumberSeparator =
-                String(formattedString[
-                    currencySymbolRange.upperBound..<formattedString
-                        .index(after: currencySymbolRange.upperBound)
-                ])
+            let separatorStart = currencySymbolRange.upperBound
+            guard separatorStart < formattedString.endIndex else { return nil }
+            currencySymbolNumberSeparator = String(formattedString[separatorStart..<formattedString.index(after: separatorStart)])
         } else {
             currencySymbolNumberSeparator =
                 String(formattedString[
@@ -85,8 +83,9 @@ extension NumberFormatter {
         var formattedSeparatorIndex: String.Index! = formattedStringWithoutCurrency.range(of: decimalSeparator)?.lowerBound
 
         if formattedSeparatorIndex == nil {
-            formattedSeparatorIndex = formattedStringWithoutCurrency.endIndex
             formattedStringWithoutCurrency = formattedStringWithoutCurrency + decimalSeparator
+            formattedSeparatorIndex = formattedStringWithoutCurrency.index(formattedStringWithoutCurrency.endIndex,
+                                                                            offsetBy: -decimalSeparator.count)
         }
 
         let formattedFractionPartRange = formattedSeparatorIndex..<formattedStringWithoutCurrency.endIndex

DashWallet/Sources/Infrastructure/Database/DatabaseConnection.swift

@@ -29,9 +29,10 @@ class DatabaseConnection: NSObject {
     var migrationManager: SQLiteMigrationManager!
 
     override init() {
-        print("SQLite: ", DatabaseConnection.storeURL().absoluteString)
+        let databaseURL = DatabaseConnection.storeURL()
+        print("SQLite: ", databaseURL.path)
         do {
-            db = try Connection(DatabaseConnection.storeURL().absoluteString)
+            db = try Connection(databaseURL.path)
             migrationManager = SQLiteMigrationManager(db: db,
                                                       migrations: DatabaseConnection.migrations(),
                                                       bundle: DatabaseConnection.migrationsBundle())
@@ -44,6 +45,12 @@ class DatabaseConnection: NSObject {
 
     @objc
     func migrateIfNeeded() throws {
+        guard let migrationManager else {
+            throw NSError(domain: "DatabaseConnection", code: 1, userInfo: [
+                NSLocalizedDescriptionKey: "The wallet database could not be opened."
+            ])
+        }
+
         if !migrationManager.hasMigrationsTable() {
             try migrationManager.createMigrationsTable()
         }
@@ -62,11 +69,8 @@ extension DatabaseConnection {
         let dirPaths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
         let docsDir = dirPaths[0] as String
 
-        guard let documentsURL = URL(string: docsDir) else {
-            fatalError("could not get user documents directory URL")
-        }
-
-        return documentsURL.appendingPathComponent(kDatabaseName)
+        return URL(fileURLWithPath: docsDir, isDirectory: true)
+            .appendingPathComponent(kDatabaseName)
     }
 
     static func migrations() -> [Migration] {

DashWallet/Sources/Infrastructure/SwiftDashSDK/SwiftDashSDKKeyMigrator.swift

@@ -203,6 +203,10 @@ final class SwiftDashSDKKeyMigrator: NSObject {
         network: Network,
         isImported: Bool
     ) throws -> Data {
+        guard !Thread.isMainThread else {
+            throw MigrationError.hostCreateOnMainThread
+        }
+
         let semaphore = DispatchSemaphore(value: 0)
         var result: Result<Data, Error>?
 
@@ -228,6 +232,7 @@ final class SwiftDashSDKKeyMigrator: NSObject {
 
     private enum MigrationError: LocalizedError {
         case hostCreateDidNotReturn
+        case hostCreateOnMainThread
     }
 
     // MARK: - Helpers

DashWallet/Sources/Infrastructure/SwiftDashSDK/SwiftDashSDKSPVCoordinator.swift

@@ -369,7 +369,7 @@ public final class SwiftDashSDKSPVCoordinator: NSObject, ObservableObject {
                 gapLimit: CoinJoinRecovery.recoveryGapLimit)
             coinJoinRecoveryWidenedNetwork = network
             Self.logger.info(
-                "🛰️ SPVCOORD :: CJTEST coinjoin recovery gap widened on \(network.rawValue, privacy: .public) to \(CoinJoinRecovery.recoveryGapLimit, privacy: .public)")
+                "🛰️ SPVCOORD :: coinjoin recovery gap widened on \(network.rawValue, privacy: .public) to \(CoinJoinRecovery.recoveryGapLimit, privacy: .public)")
         } catch {
             Self.logger.error(
                 "🛰️ SPVCOORD :: coinjoin recovery widen failed: \(String(describing: error), privacy: .public)")
@@ -452,7 +452,7 @@ public final class SwiftDashSDKSPVCoordinator: NSObject, ObservableObject {
               let network = coinJoinRecoveryWidenedNetwork,
               network == runningNetwork else { return }
 
-        Self.logger.info("🛰️ SPVCOORD :: CJTEST coinjoin recovery scan reached .synced on \(network.rawValue, privacy: .public) — marking recovered")
+        Self.logger.info("🛰️ SPVCOORD :: coinjoin recovery scan reached .synced on \(network.rawValue, privacy: .public) — marking recovered")
         CoinJoinRecovery.shared.markRecovered(for: network)
         coinJoinRecoveryWidenedNetwork = nil
     }

DashWallet/Sources/Infrastructure/SwiftDashSDK/SwiftDashSDKWalletCreator.swift

@@ -154,6 +154,10 @@ final class SwiftDashSDKWalletCreator: NSObject {
         network: Network,
         isImported: Bool
     ) throws -> Data {
+        guard !Thread.isMainThread else {
+            throw CreateError.hostCreateOnMainThread
+        }
+
         let semaphore = DispatchSemaphore(value: 0)
         var result: Result<Data, Error>?
 
@@ -179,5 +183,6 @@ final class SwiftDashSDKWalletCreator: NSObject {
 
     private enum CreateError: LocalizedError {
         case hostCreateDidNotReturn
+        case hostCreateOnMainThread
     }
 }

DashWallet/Sources/Infrastructure/SwiftDashSDK/SwiftDashSDKWalletWiper.swift

@@ -229,6 +229,14 @@ final class SwiftDashSDKWalletWiper: NSObject {
     private static func deleteWalletsFromSDK(
         _ storedWalletIdsByNetwork: [Network: Set<Data>]
     ) -> Bool {
+        // `finished.wait()` below blocks this thread until the `@MainActor`
+        // task signals it. On the main thread that task could never be
+        // scheduled, so the wait would deadlock rather than fail.
+        guard !Thread.isMainThread else {
+            logger.error("Refusing synchronous wallet deletion on the main thread")
+            return false
+        }
+
         let finished = DispatchSemaphore(value: 0)
         let result = WalletWipeResultAccumulator()
         Task { @MainActor in

DashWallet/Sources/Models/Coinbase/Accounts/Account/CBAccount.swift

@@ -109,7 +109,7 @@ extension CBAccount {
                      idem: UUID?) async throws -> (transaction: CoinbaseTransaction, walletId: Data) {
         // NOTE: Maybe better to get the address once and use it during the tx flow
         guard let destination = SwiftDashSDKReceiveAddressReader.receiveDestination() else {
-            fatalError("No wallet")
+            throw Coinbase.Error.unknownError
         }
 
         // TODO: disabled until Coinbase changes are clear

DashWallet/Sources/Models/Coinbase/Infrastructure/API/DTOs/Account/CoinbaseUserAccountData.swift

@@ -37,7 +37,7 @@ struct CoinbaseUserAccountData: Codable, Identifiable {
     var iconURL: URL {
         let code = currency.code.lowercased()
         let urlString = "https://raw.githubusercontent.com/jsupa/crypto-icons/main/icons/\(code).png"
-        return URL(string: urlString)!
+        return URL(string: urlString) ?? URL(fileURLWithPath: "/")
     }
 
     var balanceString: String {
@@ -68,7 +68,7 @@ struct CoinbaseUserAccountData: Codable, Identifiable {
         }
 
         let nf = NumberFormatter.fiatFormatter(currencyCode: App.fiatCurrency)
-        return nf.string(from: fiatAmount as NSNumber)!
+        return nf.string(from: fiatAmount as NSNumber) ?? "—"
     }
 
     var plainAmount: UInt64 {
@@ -83,7 +83,8 @@ struct CoinbaseUserAccountData: Codable, Identifiable {
     var plainAmountInDash: UInt64 {
         if currencyCode == kDashCurrency { return plainAmount }
 
-        guard let dashAmount = try? Coinbase.shared.currencyExchanger.convertToDash(amount: balance.amount.decimal()!, currency: currencyCode) else {
+        guard let amount = balance.amount.decimal(),
+              let dashAmount = try? Coinbase.shared.currencyExchanger.convertToDash(amount: amount, currency: currencyCode) else {
             return 0
         }
 

DashWallet/Sources/Models/Coinbase/Infrastructure/API/DTOs/Base/CoinbaseAmount.swift

@@ -19,13 +19,13 @@ extension Amount {
         assert(currency != kDashCurrency)
 
         guard let decimal = amount.decimal() else {
-            fatalError("Trying to convert non number string")
+            return "—"
         }
 
         let numberFormatter = NumberFormatter.fiatFormatter(currencyCode: currency)
 
         guard let string = numberFormatter.string(from: decimal as NSNumber) else {
-            fatalError("Trying to convert non number string")
+            return "—"
         }
 
         return string
@@ -35,11 +35,11 @@ extension Amount {
         assert(currency == kDashCurrency)
 
         guard let decimal = amount.decimal() else {
-            fatalError("Trying to convert non number string")
+            return "—"
         }
 
         guard let string = NumberFormatter.dashFormatter.string(from: decimal as NSNumber) else {
-            fatalError("Trying to convert non number string")
+            return "—"
         }
 
         return string

DashWallet/Sources/Models/Coinbase/Infrastructure/Currency Exchanger/CoinbaseRatesProvider.swift

@@ -45,6 +45,7 @@ extension CoinbaseRatesProvider {
 
     private func fetchPrices() {
         Task {
+            do {
             let response: BaseDataResponse<CoinbaseExchangeRate> = try await httpClient.request(.exchangeRates(kDashCurrency))
             guard let rates = response.data.rates else { return }
 
@@ -53,11 +54,14 @@ extension CoinbaseRatesProvider {
 
             for rate in rates {
                 let key = rate.key
-                let price = Decimal(string: rate.value)!
+                guard let price = Decimal(string: rate.value) else { continue }
                 array.append(.init(code: key, name: key, price: price))
             }
 
             self.updateHandler?(array)
+            } catch {
+                DWLogger.log("Coinbase exchange rates request failed: \(error.localizedDescription)")
+            }
         }
     }
 }

DashWallet/Sources/Models/Transactions/WalletSendService.swift

@@ -333,7 +333,7 @@ final class WalletSendService: NSObject {
             )
         }
 
-        Self.logger.info("💸 TXSEND :: CJTEST preparing CoinJoin sweep — balance \(amount, privacy: .public) duffs (\(Double(amount) / 1e8, privacy: .public) DASH)")
+        Self.logger.info("💸 TXSEND :: preparing CoinJoin sweep — balance \(amount, privacy: .public) duffs (\(Double(amount) / 1e8, privacy: .public) DASH)")
         try await sendAuthorizer.authorizeSend(spendAmount: amount)
 
         guard let destination = SwiftDashSDKReceiveAddressReader.receiveAddress() else {
@@ -343,13 +343,13 @@ final class WalletSendService: NSObject {
             )
         }
 
-        Self.logger.info("💸 TXSEND :: CJTEST CoinJoin sweep destination resolved \(destination, privacy: .public)")
+        Self.logger.info("💸 TXSEND :: CoinJoin sweep destination resolved \(destination, privacy: .public)")
         let txids = try SwiftDashSDKTransactionSender.sweepCoinJoin(to: destination)
         guard !txids.isEmpty else {
             // A reported-success sweep that produced no transaction is treated
             // as a failure, so the caller surfaces an error (the sweep alert)
             // rather than silently "succeeding" with the balance unchanged.
-            Self.logger.error("💸 TXSEND :: CJTEST CoinJoin sweep returned no transactions for \(amount, privacy: .public) duffs — treating as failure")
+            Self.logger.error("💸 TXSEND :: CoinJoin sweep returned no transactions for \(amount, privacy: .public) duffs — treating as failure")
             throw Self.makeError(
                 code: .coinJoinSweepUnavailable,
                 description: "CoinJoin sweep produced no transactions"
@@ -366,12 +366,12 @@ final class WalletSendService: NSObject {
         let recordedHexes: [String] = txids.map { (txid: Data) in
             txid.reversed().map { String(format: "%02x", $0) }.joined()
         }
-        Self.logger.info("💸 TXSEND :: CJTEST recorded \(txids.count, privacy: .public) sweep txid(s) in CoinJoinWithdrawalStore: \(recordedHexes.joined(separator: ","), privacy: .public)")
+        Self.logger.info("💸 TXSEND :: recorded \(txids.count, privacy: .public) sweep txid(s) in CoinJoinWithdrawalStore: \(recordedHexes.joined(separator: ","), privacy: .public)")
 
         await MainActor.run {
             SwiftDashSDKWalletState.shared.refreshCoinJoinBalance()
             let post = SwiftDashSDKWalletState.shared.coinJoinBalanceDuffs
-            Self.logger.info("💸 TXSEND :: CJTEST post-sweep CoinJoin balance \(post, privacy: .public) duffs (was \(amount, privacy: .public))")
+        Self.logger.info("💸 TXSEND :: post-sweep CoinJoin balance \(post, privacy: .public) duffs (was \(amount, privacy: .public))")
             // The per-network recovery flag is owned solely by the recovery scan-
             // completion path (SwiftDashSDKSPVCoordinator.maybeCompleteCoinJoinRecovery,
             // which marks recovered once the one-time wide scan reaches .synced). A

DashWallet/Sources/UI/Coinbase/Base/ViewModel+Coinbase.swift

@@ -65,10 +65,9 @@ extension CoinbaseTransactionSendable {
             }
         } catch {
             await MainActor.run {
-                self.transactionDelegate?.transferFromCoinbaseToWalletDidFail(with: error as! Coinbase.Error)
+                self.transactionDelegate?.transferFromCoinbaseToWalletDidFail(with: error as? Coinbase.Error ?? .unknownError)
             }
         }
     }
 }
 
-

DashWallet/Sources/UI/Coinbase/Custodial Swaps/Order Preview/Model/ConvertCryptoOrderPreviewModel.swift

@@ -91,18 +91,22 @@ extension ConvertCryptoOrderPreviewModel {
         case .origin, .purchaseAmount:
             let formatter = NumberFormatter.cryptoFormatter(currencyCode: selectedAccount.info.currencyCode, exponent: selectedAccount.info.currency.exponent)
             formatter.minimumFractionDigits = 1
-            value = formatter.string(from: Decimal(string: order.inputAmount.amount)! as NSDecimalNumber) ?? "NaN"
+            guard let amount = Decimal(string: order.inputAmount.amount) else { return "—" }
+            value = formatter.string(from: amount as NSDecimalNumber) ?? "—"
         case .destination:
             let formatter = NumberFormatter.dashFormatter
-            value = formatter.string(from: Decimal(string: order.outputAmount.amount)! as NSDecimalNumber) ?? "NaN"
+            guard let amount = Decimal(string: order.outputAmount.amount) else { return "—" }
+            value = formatter.string(from: amount as NSDecimalNumber) ?? "—"
         case .feeAmount:
             value = order.fee.formattedFiatAmount
         case .totalAmount:
-            let total = Decimal(string: order.fee.amount)! + Decimal(string: order.displayInputAmount.amount)!
+            guard let fee = Decimal(string: order.fee.amount),
+                  let input = Decimal(string: order.displayInputAmount.amount) else { return "—" }
+            let total = fee + input
             let numberFormatter = NumberFormatter.fiatFormatter(currencyCode: order.unitPrice.targetToFiat.currency)
 
             guard let string = numberFormatter.string(from: total as NSNumber) else {
-                fatalError("Trying to convert non number string")
+                return "—"
             }
 
             value = string

DashWallet/Sources/UI/Coinbase/Transfer Amount/Model/TransferAmountModel.swift

@@ -125,7 +125,7 @@ final class TransferAmountModel: CoinbaseAmountModel, CoinbaseTransactionSendabl
                 }
             } catch let error {
                 await MainActor.run {
-                    self.delegate?.transferFromCoinbaseToWalletDidFail(with: error as! Coinbase.Error)
+                    self.delegate?.transferFromCoinbaseToWalletDidFail(with: error as? Coinbase.Error ?? .unknownError)
                 }
             }
         }