MM-19574 Don't return metadata for deleted posts (#12878)

app/post_metadata.go

@@ -87,6 +87,11 @@ func (a *App) PreparePostForClient(originalPost *model.Post, isNewPost bool, isE
 
 	post.Metadata = &model.PostMetadata{}
 
+	if post.DeleteAt > 0 {
+		// Don't fill out metadata for deleted posts
+		return post
+	}
+
 	// Emojis and reaction counts
 	if emojis, reactions, err := a.getEmojisAndReactionsForPost(post); err != nil {
 		mlog.Warn("Failed to get emojis and reactions for a post", mlog.String("post_id", post.Id), mlog.Err(err))

app/post_metadata_test.go

@@ -477,6 +477,36 @@ func TestPreparePostForClient(t *testing.T) {
 			}, imageDimensions[server.URL+"/test-image1.png"])
 		})
 	})
+
+	t.Run("no metadata for deleted posts", func(t *testing.T) {
+		th := setup()
+		defer th.TearDown()
+
+		fileInfo, err := th.App.DoUploadFile(time.Now(), th.BasicTeam.Id, th.BasicChannel.Id, th.BasicUser.Id, "test.txt", []byte("test"))
+		require.Nil(t, err)
+
+		post, err := th.App.CreatePost(&model.Post{
+			Message:   "test",
+			FileIds:   []string{fileInfo.Id},
+			UserId:    th.BasicUser.Id,
+			ChannelId: th.BasicChannel.Id,
+		}, th.BasicChannel, false)
+		require.Nil(t, err)
+
+		th.AddReactionToPost(post, th.BasicUser, "taco")
+
+		post, err = th.App.DeletePost(post.Id, th.BasicUser.Id)
+		require.Nil(t, err)
+
+		// DeleteAt isn't set on the post returned by App.DeletePost
+		post.DeleteAt = model.GetMillis()
+
+		clientPost := th.App.PreparePostForClient(post, false, false)
+
+		assert.NotEqual(t, nil, clientPost.Metadata, "should've populated Metadata“")
+		assert.Nil(t, clientPost.Metadata.Reactions, "should not have populated Reactions")
+		assert.Nil(t, clientPost.Metadata.Files, "should not have populated Files")
+	})
 }
 
 func TestPreparePostForClientWithImageProxy(t *testing.T) {