Fix crash when the Prepublishing sheet is restored without a post

The sheet is a DialogFragment, so the FragmentManager restores it after a
config change or process death regardless of whether the host activity has
loaded a post, and PrepublishingHomeFragment then built its UI against an
empty EditPostRepository. Dismiss the sheet instead, and stop
EditPostRepository.status from laundering a null post through the
unannotated PostStatus.fromPost.

Fixes JETPACK-ANDROID-1EVE

Author: nbradbury

WordPress/src/main/java/org/wordpress/android/ui/posts/EditPostRepository.kt

@@ -73,7 +73,7 @@ class EditPostRepository
     val password: String
         get() = post!!.password
     val status: PostStatus
-        get() = fromPost(getPost())
+        get() = post?.let { fromPost(it) } ?: PostStatus.UNKNOWN
     val isPage: Boolean
         get() = post!!.isPage
     val isLocalDraft: Boolean

WordPress/src/main/java/org/wordpress/android/ui/posts/prepublishing/home/PrepublishingHomeFragment.kt

@@ -3,6 +3,7 @@ package org.wordpress.android.ui.posts.prepublishing.home
 import android.content.Context
 import android.os.Bundle
 import android.view.View
+import androidx.fragment.app.DialogFragment
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.ViewModelProvider
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -102,6 +103,11 @@ class PrepublishingHomeFragment : Fragment(R.layout.post_prepublishing_home_frag
             actionClickedListener?.onSubmitButtonClicked(publishPost)
         }
 
+        viewModel.dismissSheet.observeEvent(viewLifecycleOwner) {
+            // allowing state loss because this can run while the host activity is already finishing
+            (parentFragment as? DialogFragment)?.dismissAllowingStateLoss()
+        }
+
         viewModel.start(getEditPostRepository(), getSite())
     }
 

WordPress/src/main/java/org/wordpress/android/ui/posts/prepublishing/home/PrepublishingHomeViewModel.kt

@@ -23,6 +23,7 @@ import org.wordpress.android.ui.posts.prepublishing.home.usecases.GetButtonUiSta
 import org.wordpress.android.ui.posts.trackPrepublishingNudges
 import org.wordpress.android.ui.utils.UiString.UiStringRes
 import org.wordpress.android.ui.utils.UiString.UiStringText
+import org.wordpress.android.util.AppLog
 import org.wordpress.android.util.StringUtils
 import org.wordpress.android.util.analytics.AnalyticsTrackerWrapper
 import org.wordpress.android.util.merge
@@ -49,6 +50,9 @@ class PrepublishingHomeViewModel @Inject constructor(
     private val _onSubmitButtonClicked = MutableLiveData<Event<PublishPost>>()
     val onSubmitButtonClicked: LiveData<Event<PublishPost>> = _onSubmitButtonClicked
 
+    private val _dismissSheet = MutableLiveData<Event<Unit>>()
+    val dismissSheet: LiveData<Event<Unit>> = _dismissSheet
+
     private val _uiState = MutableLiveData<List<PrepublishingHomeItemUiState>>()
     private var _socialUiState: MutableLiveData<SocialUiState> = MutableLiveData(SocialUiState.Hidden)
 
@@ -68,6 +72,14 @@ class PrepublishingHomeViewModel @Inject constructor(
     fun start(editPostRepository: EditPostRepository, site: SiteModel) {
         this.editPostRepository = editPostRepository
         if (isStarted) return
+        // The sheet is a DialogFragment, so the FragmentManager can restore it after a config
+        // change or process death before the host activity has loaded a post. Close the sheet
+        // rather than building its UI against an empty repository.
+        if (!editPostRepository.hasPost()) {
+            AppLog.e(AppLog.T.POSTS, "Prepublishing sheet opened without a post; dismissing.")
+            _dismissSheet.postValue(Event(Unit))
+            return
+        }
         isStarted = true
 
         setupHomeUiState(editPostRepository, site)

WordPress/src/test/java/org/wordpress/android/ui/posts/EditPostRepositoryTest.kt

@@ -19,6 +19,7 @@ import org.wordpress.android.fluxc.model.post.PostLocation
 import org.wordpress.android.fluxc.model.post.PostStatus.DRAFT
 import org.wordpress.android.fluxc.model.post.PostStatus.PENDING
 import org.wordpress.android.fluxc.model.post.PostStatus.PUBLISHED
+import org.wordpress.android.fluxc.model.post.PostStatus.UNKNOWN
 import org.wordpress.android.fluxc.store.PostStore
 import org.wordpress.android.ui.posts.EditPostRepository.UpdatePostResult
 import org.wordpress.android.util.LocaleManagerWrapper
@@ -69,6 +70,11 @@ class EditPostRepositoryTest : BaseUnitTest() {
         assertThat(editPostRepository.isPostPublishable()).isFalse()
     }
 
+    @Test
+    fun `status is UNKNOWN before initialization`() {
+        assertThat(editPostRepository.status).isEqualTo(UNKNOWN)
+    }
+
     @Test
     fun `reads post for undo correctly`() {
         val post = PostModel()

WordPress/src/test/java/org/wordpress/android/ui/posts/PrepublishingHomeViewModelTest.kt

@@ -71,6 +71,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         ).doAnswer {
             PublishButtonUiState(it.arguments[2] as (PublishPost) -> Unit)
         }
+        whenever(editPostRepository.hasPost()).thenReturn(true)
         whenever(editPostRepository.getEditablePost()).thenReturn(PostModel())
         whenever(postSettingsUtils.getPublishDateLabel(any())).thenReturn((""))
         whenever(site.name).thenReturn("")
@@ -86,7 +87,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         val expectedActionsAmount = 3
 
         // act
-        viewModel.start(mock(), site)
+        viewModel.start(editPostRepository, site)
 
         // assert
         assertThat(viewModel.uiState.value?.filterIsInstance(HomeUiState::class.java)?.size).isEqualTo(
@@ -163,7 +164,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         val expectedActionsAmount = 1
 
         // act
-        viewModel.start(mock(), site)
+        viewModel.start(editPostRepository, site)
 
         // assert
         assertThat(viewModel.uiState.value?.filterIsInstance(HeaderUiState::class.java)?.size).isEqualTo(
@@ -177,7 +178,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         val expectedActionsAmount = 1
 
         // act
-        viewModel.start(mock(), site)
+        viewModel.start(editPostRepository, site)
 
         // assert
         assertThat(viewModel.uiState.value?.filterIsInstance(ButtonUiState::class.java)?.size).isEqualTo(
@@ -191,7 +192,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         val expectedActionType = PrepublishingScreenNavigation.Publish
 
         // act
-        viewModel.start(mock(), site)
+        viewModel.start(editPostRepository, site)
         val publishAction = getHomeUiState(expectedActionType)
         publishAction?.onNavigationActionClicked?.invoke(expectedActionType)
 
@@ -205,7 +206,7 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         val expectedActionType = PrepublishingScreenNavigation.Tags
 
         // act
-        viewModel.start(mock(), site)
+        viewModel.start(editPostRepository, site)
         val tagsAction = getHomeUiState(expectedActionType)
         tagsAction?.onNavigationActionClicked?.invoke(expectedActionType)
 
@@ -397,6 +398,19 @@ class PrepublishingHomeViewModelTest : BaseUnitTest() {
         assertThat(uiSocialState).isEqualTo(SocialUiState.Hidden)
     }
 
+    @Test
+    fun `given a repository with no post, when the viewModel is started, then the sheet is dismissed`() {
+        // arrange
+        whenever(editPostRepository.hasPost()).thenReturn(false)
+
+        // act
+        viewModel.start(editPostRepository, site)
+
+        // assert
+        assertThat(viewModel.dismissSheet.value?.peekContent()).isNotNull
+        assertThat(viewModel.uiState.value).isNull()
+    }
+
     private fun getHeaderUiState() = viewModel.uiState.value?.filterIsInstance(HeaderUiState::class.java)?.first()
 
     private fun getButtonUiState(): ButtonUiState? {