MM-14481: Do not allow to edit or delete in archived channels (#10422)

* MM-14481: Do not allow to edit or delete in archived channels

* Fixing govet

* Adding new tests

app/post.go

@@ -480,6 +480,16 @@ func (a *App) UpdatePost(post *model.Post, safeUpdate bool) (*model.Post, *model
 		}
 	}
 
+	channel, err := a.GetChannel(oldPost.ChannelId)
+	if err != nil {
+		return nil, err
+	}
+
+	if channel.DeleteAt != 0 {
+		err := model.NewAppError("UpdatePost", "api.post.update_post.can_not_update_post_in_deleted.error", nil, "", http.StatusBadRequest)
+		return nil, err
+	}
+
 	newPost := &model.Post{}
 	*newPost = *oldPost
 
@@ -559,6 +569,16 @@ func (a *App) PatchPost(postId string, patch *model.PostPatch) (*model.Post, *mo
 		return nil, err
 	}
 
+	channel, err := a.GetChannel(post.ChannelId)
+	if err != nil {
+		return nil, err
+	}
+
+	if channel.DeleteAt != 0 {
+		err = model.NewAppError("PatchPost", "api.post.patch_post.can_not_update_post_in_deleted.error", nil, "", http.StatusBadRequest)
+		return nil, err
+	}
+
 	post.Patch(patch)
 
 	updatedPost, err := a.UpdatePost(post, false)
@@ -700,6 +720,16 @@ func (a *App) DeletePost(postId, deleteByID string) (*model.Post, *model.AppErro
 	}
 	post := result.Data.(*model.Post)
 
+	channel, err := a.GetChannel(post.ChannelId)
+	if err != nil {
+		return nil, err
+	}
+
+	if channel.DeleteAt != 0 {
+		err := model.NewAppError("DeletePost", "api.post.delete_post.can_not_delete_post_in_deleted.error", nil, "", http.StatusBadRequest)
+		return nil, err
+	}
+
 	if result := <-a.Srv.Store.Post().Delete(postId, model.GetMillis(), deleteByID); result.Err != nil {
 		return nil, result.Err
 	}

app/post_test.go

@@ -308,6 +308,19 @@ func TestUpdatePostTimeLimit(t *testing.T) {
 	})
 }
 
+func TestUpdatePostInArchivedChannel(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	archivedChannel := th.CreateChannel(th.BasicTeam)
+	post := th.CreatePost(archivedChannel)
+	th.App.DeleteChannel(archivedChannel, "")
+
+	_, err := th.App.UpdatePost(post, true)
+	require.NotNil(t, err)
+	require.Equal(t, "api.post.update_post.can_not_update_post_in_deleted.error", err.Id)
+}
+
 func TestPostReplyToPostWhereRootPosterLeftChannel(t *testing.T) {
 	// This test ensures that when replying to a root post made by a user who has since left the channel, the reply
 	// post completes successfully. This is a regression test for PLT-6523.
@@ -639,6 +652,19 @@ func TestDeletePostWithFileAttachments(t *testing.T) {
 	assert.NotNil(t, err)
 }
 
+func TestDeletePostInArchivedChannel(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	archivedChannel := th.CreateChannel(th.BasicTeam)
+	post := th.CreatePost(archivedChannel)
+	th.App.DeleteChannel(archivedChannel, "")
+
+	_, err := th.App.DeletePost(post.Id, "")
+	require.NotNil(t, err)
+	require.Equal(t, "api.post.delete_post.can_not_delete_post_in_deleted.error", err.Id)
+}
+
 func TestCreatePost(t *testing.T) {
 	t.Run("call PreparePostForClient before returning", func(t *testing.T) {
 		th := Setup(t).InitBasic()
@@ -703,6 +729,19 @@ func TestPatchPost(t *testing.T) {
 	})
 }
 
+func TestPatchPostInArchivedChannel(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	archivedChannel := th.CreateChannel(th.BasicTeam)
+	post := th.CreatePost(archivedChannel)
+	th.App.DeleteChannel(archivedChannel, "")
+
+	_, err := th.App.PatchPost(post.Id, &model.PostPatch{IsPinned: model.NewBool(true)})
+	require.NotNil(t, err)
+	require.Equal(t, "api.post.patch_post.can_not_update_post_in_deleted.error", err.Id)
+}
+
 func TestUpdatePost(t *testing.T) {
 	t.Run("call PreparePostForClient before returning", func(t *testing.T) {
 		th := Setup(t).InitBasic()

i18n/en.json

@@ -1452,6 +1452,18 @@
     "id": "api.post.create_post.town_square_read_only",
     "translation": "This channel is read-only. Only members with permission can post here."
   },
+  {
+    "id": "api.post.patch_post.can_not_update_post_in_deleted.error",
+    "translation": "Can not update a post in a deleted channel."
+  },
+  {
+    "id": "api.post.update_post.can_not_update_post_in_deleted.error",
+    "translation": "Can not update a post in a deleted channel."
+  },
+  {
+    "id": "api.post.delete_post.can_not_delete_post_in_deleted.error",
+    "translation": "Can not delete a post in a deleted channel."
+  },
   {
     "id": "api.post.save_is_pinned_post.town_square_read_only",
     "translation": "This channel is read-only. Only members with permission can pin or unpin posts here."