replaced indirect expand field.Unique with unique index constraint check

daos/record_expand.go

@@ -9,6 +9,7 @@ import (
 	"github.com/pocketbase/dbx"
 	"github.com/pocketbase/pocketbase/models"
 	"github.com/pocketbase/pocketbase/models/schema"
+	"github.com/pocketbase/pocketbase/tools/dbutils"
 	"github.com/pocketbase/pocketbase/tools/inflector"
 	"github.com/pocketbase/pocketbase/tools/list"
 	"github.com/pocketbase/pocketbase/tools/security"
@@ -86,7 +87,7 @@ func (dao *Dao) expandRecords(records []*models.Record, expandPath string, fetch
 		if indirectRelFieldOptions == nil || indirectRelFieldOptions.CollectionId != mainCollection.Id {
 			return fmt.Errorf("Invalid indirect relation field path %q.", parts[0])
 		}
-		if indirectRelFieldOptions.MaxSelect != nil && *indirectRelFieldOptions.MaxSelect != 1 {
+		if indirectRelFieldOptions.IsMultiple() {
 			// for now don't allow multi-relation indirect fields expand
 			// due to eventual poor query performance with large data sets.
 			return fmt.Errorf("Multi-relation fields cannot be indirectly expanded in %q.", parts[0])
@@ -126,7 +127,7 @@ func (dao *Dao) expandRecords(records []*models.Record, expandPath string, fetch
 			MaxSelect:    nil,
 			CollectionId: indirectRel.Id,
 		}
-		if indirectRelField.Unique {
+		if isRelFieldUnique(indirectRel, indirectRelField.Name) {
 			relFieldOptions.MaxSelect = types.Pointer(1)
 		}
 		// indirect relation
@@ -269,3 +270,14 @@ func normalizeExpands(paths []string) []string {
 
 	return list.ToUniqueStringSlice(result)
 }
+
+func isRelFieldUnique(collection *models.Collection, fieldName string) bool {
+	for _, idx := range collection.Indexes {
+		parsed := dbutils.ParseIndex(idx.(string))
+		if parsed.Unique && len(parsed.Columns) == 1 && strings.EqualFold(parsed.Columns[0].Name, fieldName) {
+			return true
+		}
+	}
+
+	return false
+}

daos/record_expand_test.go

@@ -362,3 +362,57 @@ func TestExpandRecord(t *testing.T) {
 		}
 	}
 }
+
+func TestIndirectExpandSingeVsArrayResult(t *testing.T) {
+	app, _ := tests.NewTestApp()
+	defer app.Cleanup()
+
+	record, err := app.Dao().FindRecordById("demo3", "7nwo8tuiatetxdm")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// non-unique indirect expand
+	{
+		errs := app.Dao().ExpandRecord(record, []string{"demo4(rel_one_cascade)"}, func(c *models.Collection, ids []string) ([]*models.Record, error) {
+			return app.Dao().FindRecordsByIds(c.Id, ids, nil)
+		})
+		if len(errs) > 0 {
+			t.Fatal(errs)
+		}
+
+		result, ok := record.Expand()["demo4(rel_one_cascade)"].([]*models.Record)
+		if !ok {
+			t.Fatalf("Expected the expanded result to be a slice, got %v", result)
+		}
+	}
+
+	// mock a unique constraint for the rel_one_cascade field
+	{
+		demo4, err := app.Dao().FindCollectionByNameOrId("demo4")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		demo4.Indexes = append(demo4.Indexes, "create unique index idx_unique_expand on demo4 (rel_one_cascade)")
+
+		if err := app.Dao().SaveCollection(demo4); err != nil {
+			t.Fatalf("Failed to mock unique constraint: %v", err)
+		}
+	}
+
+	// non-unique indirect expand
+	{
+		errs := app.Dao().ExpandRecord(record, []string{"demo4(rel_one_cascade)"}, func(c *models.Collection, ids []string) ([]*models.Record, error) {
+			return app.Dao().FindRecordsByIds(c.Id, ids, nil)
+		})
+		if len(errs) > 0 {
+			t.Fatal(errs)
+		}
+
+		result, ok := record.Expand()["demo4(rel_one_cascade)"].(*models.Record)
+		if !ok {
+			t.Fatalf("Expected the expanded result to be a single model, got %v", result)
+		}
+	}
+}