fix crash when Account.displayName is null (#1667)

app/src/main/java/com/keylesspalace/tusky/AccountActivity.kt

@@ -458,7 +458,7 @@ class AccountActivity : BottomSheetActivity(), ActionButtonActivity, HasAndroidI
 
             loadAvatar(movedAccount.avatar, accountMovedAvatar, avatarRadius, animateAvatar)
 
-            accountMovedText.text = getString(R.string.account_moved_description, movedAccount.displayName)
+            accountMovedText.text = getString(R.string.account_moved_description, movedAccount.name)
 
             // this is necessary because API 19 can't handle vector compound drawables
             val movedIcon = ContextCompat.getDrawable(this, R.drawable.ic_briefcase)?.mutate()

app/src/main/java/com/keylesspalace/tusky/components/conversation/ConversationEntity.kt

@@ -166,7 +166,7 @@ fun Account.toEntity() =
         ConversationAccountEntity(
                 id,
                 username,
-                displayName,
+                displayName.orEmpty(),
                 avatar,
                 emojis ?: emptyList()
         )

app/src/main/java/com/keylesspalace/tusky/entity/Account.kt

@@ -31,7 +31,7 @@ data class Account(
         val id: String,
         @SerializedName("username") val localUsername: String,
         @SerializedName("acct") val username: String,
-        @SerializedName("display_name") val displayName: String,
+        @SerializedName("display_name") val displayName: String?, // should never be null per Api definition, but some servers break the contract
         val note: @WriteWith<SpannedParceler>() Spanned,
         val url: String,
         val avatar: String,
@@ -49,7 +49,7 @@ data class Account(
 ) : Parcelable {
 
     val name: String
-        get() = if (displayName.isEmpty()) {
+        get() = if (displayName.isNullOrEmpty()) {
             localUsername
         } else displayName
 

app/src/main/java/com/keylesspalace/tusky/repository/TimelineRepository.kt

@@ -298,7 +298,7 @@ fun Account.toEntity(accountId: Long, gson: Gson): TimelineAccountEntity {
             timelineUserId = accountId,
             localUsername = localUsername,
             username = username,
-            displayName = displayName,
+            displayName = displayName.orEmpty(),
             url = url,
             avatar = avatar,
             emojis = gson.toJson(emojis),