Alerting: Do not record rule version if no difference (#100364)

pkg/services/ngalert/store/alert_rule.go

@@ -329,7 +329,13 @@ func (st DBstore) UpdateAlertRules(ctx context.Context, user *ngmodels.UserUID,
 			v := alertRuleToAlertRuleVersion(converted)
 			v.Version++
 			v.ParentVersion = r.Existing.Version
-			ruleVersions = append(ruleVersions, v)
+
+			// check if there is diff between existing and new, and if no, skip saving version.
+			existingConverted, err := alertRuleFromModelsAlertRule(*r.Existing)
+			if err != nil || !alertRuleToAlertRuleVersion(existingConverted).EqualSpec(v) {
+				ruleVersions = append(ruleVersions, v)
+			}
+
 			keys = append(keys, ngmodels.AlertRuleKey{OrgID: r.New.OrgID, UID: r.New.UID})
 		}
 		if len(ruleVersions) > 0 {

pkg/services/ngalert/store/alert_rule_test.go

@@ -73,6 +73,16 @@ func TestIntegrationUpdateAlertRules(t *testing.T) {
 
 		require.NoError(t, err)
 		require.Equal(t, rule.Version+1, dbrule.Version)
+
+		t.Run("should create version record", func(t *testing.T) {
+			var count int64
+			err = sqlStore.WithDbSession(context.Background(), func(sess *db.Session) error {
+				count, err = sess.Table(alertRuleVersion{}).Where("rule_uid = ?", rule.UID).Count()
+				return err
+			})
+			require.NoError(t, err)
+			require.EqualValues(t, 1, count) // only the current version, insert did not create version.
+		})
 	})
 
 	t.Run("updating record field should increase version", func(t *testing.T) {
@@ -191,6 +201,32 @@ func TestIntegrationUpdateAlertRules(t *testing.T) {
 			assert.Nil(t, dbrule.UpdatedBy)
 		})
 	})
+
+	t.Run("should save noop update", func(t *testing.T) {
+		rule := createRule(t, store, gen)
+		newRule := models.CopyRule(rule)
+		err := store.UpdateAlertRules(context.Background(), &usr, []models.UpdateRule{{
+			Existing: rule,
+			New:      *newRule,
+		},
+		})
+		require.NoError(t, err)
+
+		newRule, err = store.GetAlertRuleByUID(context.Background(), &models.GetAlertRuleByUIDQuery{UID: rule.UID})
+		require.NoError(t, err)
+
+		assert.Equal(t, rule.Version+1, newRule.Version)
+
+		t.Run("should not create version record", func(t *testing.T) {
+			var count int64
+			err = sqlStore.WithDbSession(context.Background(), func(sess *db.Session) error {
+				count, err = sess.Table(alertRuleVersion{}).Where("rule_uid = ?", rule.UID).Count()
+				return err
+			})
+			require.NoError(t, err)
+			require.EqualValues(t, 1, count) // only the current version
+		})
+	})
 }
 
 func TestIntegrationUpdateAlertRulesWithUniqueConstraintViolation(t *testing.T) {