[MM-56174] Account for archived channels in channel member for post permission check (#25837)

* [MM-56174] Account for archived channels in channel member for post permission check

* Add tests

server/channels/app/authorization_test.go

@@ -667,3 +667,107 @@ func TestHasPermissionToReadChannel(t *testing.T) {
 		})
 	}
 }
+
+func TestSessionHasPermissionToChannelByPost(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	session, err := th.App.CreateSession(th.Context, &model.Session{
+		UserId: th.BasicUser.Id,
+		Roles:  model.SystemUserRoleId,
+	})
+	require.Nil(t, err)
+
+	session2, err := th.App.CreateSession(th.Context, &model.Session{
+		UserId: th.BasicUser2.Id,
+		Roles:  model.SystemUserRoleId,
+	})
+	require.Nil(t, err)
+
+	channel := th.CreateChannel(th.Context, th.BasicTeam)
+	th.App.AddUserToChannel(th.Context, th.BasicUser, channel, false)
+	post := th.CreatePost(channel)
+
+	archivedChannel := th.CreateChannel(th.Context, th.BasicTeam)
+	archivedPost := th.CreatePost(archivedChannel)
+	th.App.DeleteChannel(th.Context, archivedChannel, th.SystemAdminUser.Id)
+
+	t.Run("read channel", func(t *testing.T) {
+		require.Equal(t, true, th.App.SessionHasPermissionToChannelByPost(*session, post.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.SessionHasPermissionToChannelByPost(*session2, post.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read archived channel - setting off", func(t *testing.T) {
+		th.App.UpdateConfig(func(cfg *model.Config) {
+			cfg.TeamSettings.ExperimentalViewArchivedChannels = model.NewBool(false)
+		})
+		require.Equal(t, false, th.App.SessionHasPermissionToChannelByPost(*session, archivedPost.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.SessionHasPermissionToChannelByPost(*session2, archivedPost.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read archived channel - setting on", func(t *testing.T) {
+		th.App.UpdateConfig(func(cfg *model.Config) {
+			cfg.TeamSettings.ExperimentalViewArchivedChannels = model.NewBool(true)
+		})
+		require.Equal(t, true, th.App.SessionHasPermissionToChannelByPost(*session, archivedPost.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.SessionHasPermissionToChannelByPost(*session2, archivedPost.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read public channel", func(t *testing.T) {
+		require.Equal(t, true, th.App.SessionHasPermissionToChannelByPost(*session, post.Id, model.PermissionReadPublicChannel))
+		require.Equal(t, true, th.App.SessionHasPermissionToChannelByPost(*session2, post.Id, model.PermissionReadPublicChannel))
+	})
+
+	t.Run("read channel - user is admin", func(t *testing.T) {
+		adminSession, err := th.App.CreateSession(th.Context, &model.Session{
+			UserId: th.SystemAdminUser.Id,
+			Roles:  model.SystemAdminRoleId,
+		})
+		require.Nil(t, err)
+
+		require.Equal(t, true, th.App.SessionHasPermissionToChannelByPost(*adminSession, post.Id, model.PermissionReadChannel))
+	})
+}
+
+func TestHasPermissionToChannelByPost(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	channel := th.CreateChannel(th.Context, th.BasicTeam)
+	th.App.AddUserToChannel(th.Context, th.BasicUser, channel, false)
+	post := th.CreatePost(channel)
+
+	archivedChannel := th.CreateChannel(th.Context, th.BasicTeam)
+	archivedPost := th.CreatePost(archivedChannel)
+	th.App.DeleteChannel(th.Context, archivedChannel, th.SystemAdminUser.Id)
+
+	t.Run("read channel", func(t *testing.T) {
+		require.Equal(t, true, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser.Id, post.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser2.Id, post.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read archived channel - setting off", func(t *testing.T) {
+		th.App.UpdateConfig(func(cfg *model.Config) {
+			cfg.TeamSettings.ExperimentalViewArchivedChannels = model.NewBool(false)
+		})
+		require.Equal(t, false, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser.Id, archivedPost.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser2.Id, archivedPost.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read archived channel - setting on", func(t *testing.T) {
+		th.App.UpdateConfig(func(cfg *model.Config) {
+			cfg.TeamSettings.ExperimentalViewArchivedChannels = model.NewBool(true)
+		})
+		require.Equal(t, true, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser.Id, archivedPost.Id, model.PermissionReadChannel))
+		require.Equal(t, false, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser2.Id, archivedPost.Id, model.PermissionReadChannel))
+	})
+
+	t.Run("read public channel", func(t *testing.T) {
+		require.Equal(t, true, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser.Id, post.Id, model.PermissionReadPublicChannel))
+		require.Equal(t, true, th.App.HasPermissionToChannelByPost(th.Context, th.BasicUser2.Id, post.Id, model.PermissionReadPublicChannel))
+	})
+
+	t.Run("read channel - user is admin", func(t *testing.T) {
+		require.Equal(t, true, th.App.HasPermissionToChannelByPost(th.Context, th.SystemAdminUser.Id, post.Id, model.PermissionReadChannel))
+	})
+}