Switch to DB indexer if the sort is based on label scope.

Author: telackey

modules/indexer/issues/indexer.go

@@ -8,10 +8,12 @@ import (
 	"fmt"
 	"os"
 	"runtime/pprof"
+	"strings"
 	"sync/atomic"
 	"time"
 
 	db_model "code.gitea.io/gitea/models/db"
+	issue_model "code.gitea.io/gitea/models/issues"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/indexer/issues/bleve"
@@ -293,6 +295,11 @@ func SearchIssues(ctx context.Context, opts *SearchOptions) ([]int64, int64, err
 		indexer = db.NewIndexer()
 	}
 
+	if strings.HasPrefix(string(opts.SortBy), issue_model.ScopeSortPrefix) {
+		// Sorting by label scope is currently only supported by the DB indexer.
+		indexer = db.NewIndexer()
+	}
+
 	result, err := indexer.Search(ctx, opts)
 	if err != nil {
 		return nil, 0, err