Add some logging around SVRB.

app/src/main/java/org/thoughtcrime/securesms/backup/v2/BackupRepository.kt

@@ -1819,7 +1819,7 @@ object BackupRepository {
 
     val forwardSecrecyMetadata = EncryptedBackupReader.readForwardSecrecyMetadata(tempBackupFile.inputStream())
     if (forwardSecrecyMetadata == null) {
-      Log.w(TAG, "Failed to read forward secrecy metadata!")
+      Log.w(TAG, "[remoteRestore] Downloaded the backup file, but failed to read its forward secrecy metadata!")
       return RemoteRestoreResult.Failure
     }
 
@@ -2007,8 +2007,14 @@ object BackupRepository {
     ).encodeByteString()
   }
 
+  /**
+   * Reads the forward secrecy metadata out of the header of the remote backup file, or null if the file has none.
+   *
+   * Note that the two network steps here can fail with the same error types, so each one logs which step it was.
+   */
   suspend fun getRemoteBackupForwardSecrecyMetadata(): Either<ArchiveError.BackupFileError, ByteArray?> {
     return archiveService.getMessageBackupFileLocation()
+      .onLeft { Log.w(TAG, "[getRemoteBackupForwardSecrecyMetadata] Failed to get the backup file location: ${it::class.simpleName}", it.cause, true) }
       .flatMap { location ->
         val headers = location.cdnCredentials.toMutableMap().apply {
           this["range"] = "bytes=0-${EncryptedBackupReader.BACKUP_SECRET_METADATA_UPPERBOUND - 1}"
@@ -2017,6 +2023,7 @@ object BackupRepository {
         AppDependencies.signalServiceMessageReceiver
           .retrieveBackupForwardSecretMetadataBytes(location.cdn, headers, location.path, EncryptedBackupReader.BACKUP_SECRET_METADATA_UPPERBOUND)
           .toArchiveResult()
+          .onLeft { Log.w(TAG, "[getRemoteBackupForwardSecrecyMetadata] Got a backup file location on cdn ${location.cdn}, but failed to read the header: ${it::class.simpleName}", it.cause, true) }
       }
       .map { bytes -> EncryptedBackupReader.readForwardSecrecyMetadata(ByteArrayInputStream(bytes)) }
   }

app/src/main/java/org/thoughtcrime/securesms/jobs/BackupMessagesJob.kt

@@ -252,16 +252,22 @@ class BackupMessagesJob private constructor(
         }
       }
 
-      if (SignalStore.backup.backupSecretRestoreRequired) {
+      val svrbReInitRan = SignalStore.backup.backupSecretRestoreRequired
+      if (svrbReInitRan) {
         Log.i(TAG, "[svrb-restore] First backup of re-registered account without remote restore, read remote data if available to re-init")
 
         val forwardSecrecyMetadata: ByteArray? = when (val result = BackupRepository.getRemoteBackupForwardSecrecyMetadata()) {
-          is Either.Right -> result.value
+          is Either.Right -> {
+            if (result.value == null) {
+              Log.w(TAG, "[svrb-restore] Read the remote backup header, but it contained no forward secrecy metadata!", true)
+            }
+            result.value
+          }
           is Either.Left -> when (val error = result.value) {
             is ArchiveError.CredentialError.Unauthorized,
             is ArchiveError.EntitlementError.NotEntitled,
             is ArchiveError.CredentialError.NotFound -> {
-              Log.i(TAG, "[svrb-restore] No backup data found, continuing.", true)
+              Log.i(TAG, "[svrb-restore] No backup data found (${error::class.simpleName}), continuing.", true)
               null
             }
             is ArchiveError.CredentialError.ZkVerificationFailed -> {
@@ -315,13 +321,16 @@ class BackupMessagesJob private constructor(
               return Result.fatalFailure(RuntimeException(result.throwable))
             }
           }
+        } else {
+          Log.w(TAG, "[svrb-restore] No remote forward secrecy metadata to restore from, skipping the SVRB restore.", true)
         }
 
+        Log.i(TAG, "[svrb-restore] Re-init finished. Have local secret data: ${SignalStore.backup.nextBackupSecretData != null}", true)
         SignalStore.backup.backupSecretRestoreRequired = false
       }
 
       val backupSecretData = SignalStore.backup.nextBackupSecretData ?: run {
-        Log.i(TAG, "First SVRB backup! Creating new backup chain.", true)
+        Log.i(TAG, "First SVRB backup! Creating new backup chain. (reInitRan: $svrbReInitRan)", true)
         val secretData = SignalNetwork.svrBApi.createNewBackupChain(auth, SignalStore.backup.messageBackupKey)
         SignalStore.backup.nextBackupSecretData = secretData
         secretData

feature/registration/src/main/java/org/signal/registration/screens/remotebackuprestore/RemoteBackupRestoreViewModel.kt

@@ -48,6 +48,9 @@ class RemoteBackupRestoreViewModel(
   private val _state = MutableStateFlow(RemoteBackupRestoreState(aep))
   val state: StateFlow<RemoteBackupRestoreState> = _state.asStateFlow()
 
+  /** Logging only. Each attempt costs an SVRB guess, so it's useful to know how many were spent. */
+  private var restoreAttempts = 0
+
   init {
     _state
       .throttleLatest(1.seconds) { it.restoreState != RemoteBackupRestoreState.RestoreState.InProgress }
@@ -127,6 +130,8 @@ class RemoteBackupRestoreViewModel(
 
   private fun restoreBackup() {
     viewModelScope.launch {
+      restoreAttempts++
+      Log.i(TAG, "[restoreBackup] Starting restore attempt #$restoreAttempts.")
       repository.restoreRemoteBackup(_state.value.aep).collect { progress ->
         when (progress) {
           is RemoteBackupRestoreProgress.Downloading -> {
@@ -187,7 +192,7 @@ class RemoteBackupRestoreViewModel(
             )
           }
           is RemoteBackupRestoreProgress.PermanentSvrBFailure -> {
-            Log.w(TAG, "[restoreBackup] Remote restore failed: permanent SVRB failure.")
+            Log.w(TAG, "[restoreBackup] Remote restore failed: permanent SVRB failure. (attempt #$restoreAttempts)")
             _state.value = _state.value.copy(
               restoreState = RemoteBackupRestoreState.RestoreState.PermanentSvrBFailure,
               restoreProgress = null