Fix crash with assignees in MergeRequest.

app/src/main/java/ru/terrakok/gitlabclient/entity/issue/Issue.kt

@@ -15,7 +15,8 @@ data class Issue(
     @SerializedName("author") val author: ShortUser,
     @SerializedName("milestone") val milestone: Milestone?,
     @SerializedName("project_id") val projectId: Long,
-    @SerializedName("assignees") val assignees: List<ShortUser>,
+    // Assignees can be null in MergeRequest, so assume it can be null too.
+    @SerializedName("assignees") val assignees: List<ShortUser>?,
     @SerializedName("updated_at") val updatedAt: ZonedDateTime?,
     @SerializedName("title") val title: String?,
     @SerializedName("created_at") val createdAt: ZonedDateTime,
@@ -35,5 +36,6 @@ data class Issue(
     @SerializedName("merge_requests_count") val relatedMergeRequestCount: Int,
     @SerializedName("time_stats") val timeStats: TimeStats,
     @SerializedName("weight") val weight: Int?,
-    @SerializedName("discussion_locked") val discussionLocked: Boolean
+    @SerializedName("discussion_locked") val discussionLocked: Boolean,
+    @SerializedName("assignee") val assignee: ShortUser?
 )
\ No newline at end of file

app/src/main/java/ru/terrakok/gitlabclient/entity/mergerequest/MergeRequest.kt

@@ -42,7 +42,8 @@ data class MergeRequest(
     @SerializedName("merged_by") val mergedBy: ShortUser?,
     @SerializedName("merged_at") val mergedAt: ZonedDateTime?,
     @SerializedName("changes") val changes: List<MergeRequestChange>?,
-    @SerializedName("assignees") val assignees: List<ShortUser>,
+    // It sometimes can be null.
+    @SerializedName("assignees") val assignees: List<ShortUser>?,
     @SerializedName("time_stats") val timeStats: TimeStats,
     @SerializedName("discussion_locked") val discussionLocked: Boolean
 )

app/src/main/java/ru/terrakok/gitlabclient/entity/target/Target.kt

@@ -53,7 +53,6 @@ abstract class Target {
     val title get() = _title!!
     val state get() = _state!!
     val labels get() = _labels!!
-    val assignees get() = _assignees!!
     val userNotesCount get() = _userNotesCount!!
     val upVotes get() = _upVotes!!
     val downVotes get() = _downVotes!!

app/src/main/java/ru/terrakok/gitlabclient/ui/issue/IssueInfoFragment.kt

@@ -34,7 +34,7 @@ class IssueInfoFragment : BaseFragment(), IssueInfoView {
 
     override fun showInfo(issue: Issue) {
         with(issue) {
-            showAssignees(assignees)
+            showAssignees(assignees ?: assignee?.let { listOf(it) } ?: emptyList())
             showMilestone(milestone)
             showDueDate(dueDate)
             showTimeStats(timeStats)

app/src/main/java/ru/terrakok/gitlabclient/ui/mergerequest/MergeRequestInfoFragment.kt

@@ -35,7 +35,7 @@ class MergeRequestInfoFragment : BaseFragment(), MergeRequestInfoView {
 
     override fun showInfo(mr: MergeRequest) {
         with(mr) {
-            showAssignees(assignees)
+            showAssignees(assignees ?: assignee?.let { listOf(it) } ?: emptyList())
             showMilestone(milestone)
             showMergeStatus(state, mergeStatus)
             showTimeStats(timeStats)