New: Improve behavior and messaging when an account is missing.

Scanning without an account setup is a programming error and prior to this change it wasted a lot of resources and would always crash eventually. Now, this error is caught sooner and surfaced with a clear message.

src/main/java/cash/z/ecc/android/sdk/block/CompactBlockProcessor.kt

@@ -375,22 +375,25 @@ class CompactBlockProcessor(
      */
     private suspend fun verifySetup() {
         // verify that the data is initialized
-        var error = if (!repository.isInitialized()) {
-            CompactBlockProcessorException.Uninitialized
-        } else {
-            // verify that the server is correct
-            downloader.getServerInfo().let { info ->
-                val clientBranch = "%x".format(rustBackend.getBranchIdForHeight(info.blockHeight.toInt()))
-                val network = rustBackend.network.networkName
-                when {
-                    !info.matchingNetwork(network) -> MismatchedNetwork(clientNetwork = network, serverNetwork = info.chainName)
-                    !info.matchingConsensusBranchId(clientBranch) -> MismatchedBranch(clientBranch = clientBranch, serverBranch = info.consensusBranchId, networkName = network)
-                    else -> null
+        var error = when {
+            !repository.isInitialized() -> CompactBlockProcessorException.Uninitialized
+            repository.getAccountCount() == 0 -> CompactBlockProcessorException.NoAccount
+            else -> {
+                // verify that the server is correct
+                downloader.getServerInfo().let { info ->
+                    val clientBranch = "%x".format(rustBackend.getBranchIdForHeight(info.blockHeight.toInt()))
+                    val network = rustBackend.network.networkName
+                    when {
+                        !info.matchingNetwork(network) -> MismatchedNetwork(clientNetwork = network, serverNetwork = info.chainName)
+                        !info.matchingConsensusBranchId(clientBranch) -> MismatchedBranch(clientBranch = clientBranch, serverBranch = info.consensusBranchId, networkName = network)
+                        else -> null
+                    }
                 }
             }
         }
 
         if (error != null) {
+            twig("Validating setup prior to scanning . . . ISSUE FOUND! - ${error.javaClass.simpleName}")
             // give listener a chance to override
             if (onSetupErrorListener?.invoke(error) != true) {
                 throw error

src/main/java/cash/z/ecc/android/sdk/db/DerivedDataDb.kt

@@ -227,6 +227,9 @@ interface SentDao {
 
 @Dao
 interface AccountDao {
+    @Query("SELECT COUNT(account) FROM accounts")
+    fun count(): Int
+
     @Query(
         """
         SELECT account AS accountId,

src/main/java/cash/z/ecc/android/sdk/exception/Exceptions.kt

@@ -83,6 +83,10 @@ sealed class CompactBlockProcessorException(message: String, cause: Throwable? =
             " initialized. Verify that the seed phrase was properly created or imported. If so, then this problem" +
             " can be fixed by re-importing the wallet."
     )
+    object NoAccount : CompactBlockProcessorException(
+        "Attempting to scan without an account. This is probably a setup error or a race condition."
+    )
+
     open class EnhanceTransactionError(message: String, val height: Int, cause: Throwable) : CompactBlockProcessorException(message, cause) {
         class EnhanceTxDownloadError(height: Int, cause: Throwable) : EnhanceTransactionError("Error while attempting to download a transaction to enhance", height, cause)
         class EnhanceTxDecryptError(height: Int, cause: Throwable) : EnhanceTransactionError("Error while attempting to decrypt and store a transaction to enhance", height, cause)

src/main/java/cash/z/ecc/android/sdk/transaction/PagedTransactionRepository.kt

@@ -105,6 +105,8 @@ open class PagedTransactionRepository(
 
     override suspend fun getAccount(accountId: Int): UnifiedAddressAccount? = accounts.findAccountById(accountId)
 
+    override suspend fun getAccountCount(): Int = accounts.count()
+
     /**
      * Close the underlying database.
      */

src/main/java/cash/z/ecc/android/sdk/transaction/TransactionRepository.kt

@@ -86,6 +86,8 @@ interface TransactionRepository {
 
     suspend fun getAccount(accountId: Int): UnifiedAddressAccount?
 
+    suspend fun getAccountCount(): Int
+
     //
     // Transactions
     //

src/main/rust/lib.rs

@@ -789,7 +789,7 @@ pub unsafe extern "C" fn Java_cash_z_ecc_android_sdk_jni_RustBackend_scanBlocks(
 
         match scan_cached_blocks(&network, &db_cache, &mut db_data, None) {
             Ok(()) => Ok(JNI_TRUE),
-            Err(e) => Err(format_err!("Error while scanning blocks: {}", e)),
+            Err(e) => Err(format_err!("Rust error while scanning blocks: {}", e)),
         }
     });
     unwrap_exc_or(&env, res, JNI_FALSE)
@@ -884,7 +884,7 @@ pub unsafe extern "C" fn Java_cash_z_ecc_android_sdk_jni_RustBackend_scanBlockBa
 
         match scan_cached_blocks(&network, &db_cache, &mut db_data, Some(limit as u32)) {
             Ok(()) => Ok(JNI_TRUE),
-            Err(e) => Err(format_err!("Error while scanning blocks: {}", e)),
+            Err(e) => Err(format_err!("Rust error while scanning block batch: {}", e)),
         }
     });
     unwrap_exc_or(&env, res, JNI_FALSE)