Add logic to validate processor setup.

src/main/java/cash/z/wallet/sdk/block/CompactBlockProcessor.kt

@@ -113,8 +113,8 @@ class CompactBlockProcessor(
      * return the block height where an error was found.
      */
     private suspend fun processNewBlocks(): Int = withContext(IO) {
+        verifySetup()
         twig("beginning to process new blocks (with lower bound: $lowerBoundHeight)...")
-
         // Get the latest info (but don't transmit it on the channel) and then use that to update the scan/download ranges
         ProcessorInfo(
             networkBlockHeight = downloader.getLatestBlockHeight(),
@@ -158,6 +158,10 @@ class CompactBlockProcessor(
 
     }
 
+    private fun verifySetup() {
+        if (!repository.isInitialized()) throw CompactBlockProcessorException.Uninitialized
+    }
+
     @VisibleForTesting //allow mocks to verify how this is called, rather than the downloader, which is more complex
     internal suspend fun downloadNewBlocks(range: IntRange) = withContext<Unit>(IO) {
         if (range.isEmpty()) {

src/main/java/cash/z/wallet/sdk/exception/Exceptions.kt

@@ -41,6 +41,9 @@ sealed class CompactBlockProcessorException(message: String, cause: Throwable? =
     class FailedReorgRepair(message: String) : CompactBlockProcessorException(message)
     object FailedScan : CompactBlockProcessorException("Error while scanning blocks. This most " +
             "likely means a block is missing or a reorg was mishandled. See Rust logs for details.")
+    object Uninitialized : CompactBlockProcessorException("Cannot process blocks because the wallet has not been" +
+            " initialized. Verify that the seed phrase was properly created or imported. If so, then this problem" +
+            " can be fixed by re-importing the wallet.")
 }
 
 sealed class CompactBlockStreamException(message: String, cause: Throwable? = null) : SdkException(message, cause) {
@@ -77,8 +80,8 @@ sealed class InitializerException(message: String, cause: Throwable? = null) :
             " because it already exists in $dbPath", cause)
     object DatabasePathException :
         InitializerException("Critical failure to locate path for storing databases. Perhaps this" +
-                " device prevents apps from storing data? We cannot manage initialize the wallet" +
-                " unless we can store data.")
+                " device prevents apps from storing data? We cannot initialize the wallet unless" +
+                " we can store data.")
 }
 
 sealed class LightwalletException(message: String, cause: Throwable? = null) : SdkException(message, cause) {