MM-23876: Fix for patching channel moderations with a null team schem… (#14239)

* MM-23876: Fix for patching channel moderations with a null team scheme channel guest role.

* MM-23876: Tests the moderations response.

api4/channel_test.go

@@ -3282,4 +3282,69 @@ func TestPatchChannelModerations(t *testing.T) {
 		require.NotEqual(t, scheme.DeleteAt, int64(0))
 	})
 
+	t.Run("Does not return an error if the team scheme has a blank DefaultChannelGuestRole field", func(t *testing.T) {
+		team := th.BasicTeam
+		scheme := th.SetupTeamScheme()
+		scheme.DefaultChannelGuestRole = ""
+
+		mockStore := mocks.Store{}
+		mockSchemeStore := mocks.SchemeStore{}
+		mockSchemeStore.On("Get", mock.Anything).Return(scheme, nil)
+		mockSchemeStore.On("Save", mock.Anything).Return(scheme, nil)
+		mockSchemeStore.On("Delete", mock.Anything).Return(scheme, nil)
+		mockStore.On("Scheme").Return(&mockSchemeStore)
+		mockStore.On("Team").Return(th.App.Srv().Store.Team())
+		mockStore.On("Channel").Return(th.App.Srv().Store.Channel())
+		mockStore.On("User").Return(th.App.Srv().Store.User())
+		mockStore.On("Post").Return(th.App.Srv().Store.Post())
+		mockStore.On("FileInfo").Return(th.App.Srv().Store.FileInfo())
+		mockStore.On("Webhook").Return(th.App.Srv().Store.Webhook())
+		mockStore.On("System").Return(th.App.Srv().Store.System())
+		mockStore.On("License").Return(th.App.Srv().Store.License())
+		mockStore.On("Role").Return(th.App.Srv().Store.Role())
+		mockStore.On("Close").Return(nil)
+		th.App.Srv().Store = &mockStore
+
+		team.SchemeId = &scheme.Id
+		_, err := th.App.UpdateTeamScheme(team)
+		require.Nil(t, err)
+
+		moderations, res := th.SystemAdminClient.PatchChannelModerations(channel.Id, emptyPatch)
+		require.Nil(t, res.Error)
+		require.Equal(t, len(moderations), 4)
+		for _, moderation := range moderations {
+			if moderation.Name == "manage_members" {
+				require.Empty(t, moderation.Roles.Guests)
+			} else {
+				require.Equal(t, moderation.Roles.Guests.Value, false)
+				require.Equal(t, moderation.Roles.Guests.Enabled, false)
+			}
+
+			require.Equal(t, moderation.Roles.Members.Value, true)
+			require.Equal(t, moderation.Roles.Members.Enabled, true)
+		}
+
+		patch := []*model.ChannelModerationPatch{
+			{
+				Name:  &createPosts,
+				Roles: &model.ChannelModeratedRolesPatch{Members: model.NewBool(true)},
+			},
+		}
+
+		moderations, res = th.SystemAdminClient.PatchChannelModerations(channel.Id, patch)
+		require.Nil(t, res.Error)
+		require.Equal(t, len(moderations), 4)
+		for _, moderation := range moderations {
+			if moderation.Name == "manage_members" {
+				require.Empty(t, moderation.Roles.Guests)
+			} else {
+				require.Equal(t, moderation.Roles.Guests.Value, false)
+				require.Equal(t, moderation.Roles.Guests.Enabled, false)
+			}
+
+			require.Equal(t, moderation.Roles.Members.Value, true)
+			require.Equal(t, moderation.Roles.Members.Enabled, true)
+		}
+	})
+
 }

app/channel.go

@@ -726,7 +726,7 @@ func (a *App) GetChannelModerationsForChannel(channel *model.Channel) ([]*model.
 	}
 
 	var higherScopedGuestRole *model.Role
-	if len(guestRoleName) > 0 {
+	if len(higherScopedGuestRoleName) > 0 {
 		higherScopedGuestRole, err = a.GetRoleByName(higherScopedGuestRoleName)
 		if err != nil {
 			return nil, err
@@ -738,19 +738,30 @@ func (a *App) GetChannelModerationsForChannel(channel *model.Channel) ([]*model.
 
 // PatchChannelModerationsForChannel Updates a channels scheme roles based on a given ChannelModerationPatch, if the permissions match the higher scoped role the scheme is deleted.
 func (a *App) PatchChannelModerationsForChannel(channel *model.Channel, channelModerationsPatch []*model.ChannelModerationPatch) ([]*model.ChannelModeration, *model.AppError) {
-	higherScopedGuestRoleName, higherScopedMemberRoleName, _, _ := a.GetTeamSchemeChannelRoles(channel.TeamId)
+	higherScopedGuestRoleName, higherScopedMemberRoleName, _, err := a.GetTeamSchemeChannelRoles(channel.TeamId)
+	if err != nil {
+		return nil, err
+	}
+
 	higherScopedMemberRole, err := a.GetRoleByName(higherScopedMemberRoleName)
 	if err != nil {
 		return nil, err
 	}
 
-	higherScopedGuestRole, err := a.GetRoleByName(higherScopedGuestRoleName)
-	if err != nil {
-		return nil, err
+	var higherScopedGuestRole *model.Role
+	if len(higherScopedGuestRoleName) > 0 {
+		higherScopedGuestRole, err = a.GetRoleByName(higherScopedGuestRoleName)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	higherScopedMemberPermissions := higherScopedMemberRole.GetChannelModeratedPermissions(channel.Type)
-	higherScopedGuestPermissions := higherScopedGuestRole.GetChannelModeratedPermissions(channel.Type)
+
+	var higherScopedGuestPermissions map[string]bool
+	if higherScopedGuestRole != nil {
+		higherScopedGuestPermissions = higherScopedGuestRole.GetChannelModeratedPermissions(channel.Type)
+	}
 
 	for _, moderationPatch := range channelModerationsPatch {
 		if moderationPatch.Roles.Members != nil && *moderationPatch.Roles.Members && !higherScopedMemberPermissions[*moderationPatch.Name] {
@@ -772,19 +783,29 @@ func (a *App) PatchChannelModerationsForChannel(channel *model.Channel, channelM
 		mlog.Info("Permission scheme created.", mlog.String("channel_id", channel.Id), mlog.String("channel_name", channel.Name))
 	}
 
-	guestRoleName, memberRoleName, _, _ := a.GetSchemeRolesForChannel(channel.Id)
+	guestRoleName, memberRoleName, _, err := a.GetSchemeRolesForChannel(channel.Id)
+	if err != nil {
+		return nil, err
+	}
+
 	memberRole, err := a.GetRoleByName(memberRoleName)
 	if err != nil {
 		return nil, err
 	}
 
-	guestRole, err := a.GetRoleByName(guestRoleName)
-	if err != nil {
-		return nil, err
+	var guestRole *model.Role
+	if len(guestRoleName) > 0 {
+		guestRole, err = a.GetRoleByName(guestRoleName)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	memberRolePatch := memberRole.RolePatchFromChannelModerationsPatch(channelModerationsPatch, "members")
-	guestRolePatch := guestRole.RolePatchFromChannelModerationsPatch(channelModerationsPatch, "guests")
+	var guestRolePatch *model.RolePatch
+	if guestRole != nil {
+		guestRolePatch = guestRole.RolePatchFromChannelModerationsPatch(channelModerationsPatch, "guests")
+	}
 
 	for _, channelModerationPatch := range channelModerationsPatch {
 		permissionModified := *channelModerationPatch.Name

model/role.go

@@ -204,6 +204,10 @@ func PermissionsChangedByPatch(role *Role, patch *RolePatch) []string {
 func ChannelModeratedPermissionsChangedByPatch(role *Role, patch *RolePatch) []string {
 	var result []string
 
+	if role == nil {
+		return result
+	}
+
 	if patch.Permissions == nil {
 		return result
 	}