[release-11.6.2] Alerting: Ensure field validators return the proper type (#105284)

Alerting: Ensure field validators return the proper type (#104050)

* Ensure field validators return the proper type

This ensures correct error propagation through services up to
the API layer.

* Move error wrapping up to call site

(cherry picked from commit 820c338414)

pkg/services/ngalert/models/alert_rule.go

@@ -624,7 +624,7 @@ func (alertRule *AlertRule) ValidateAlertRule(cfg setting.UnifiedAlertingSetting
 		err = validateAlertRuleFields(alertRule)
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf("%w: %s", ErrAlertRuleFailedValidation, err)
 	}
 
 	if alertRule.For < 0 {
@@ -665,10 +665,10 @@ func validateAlertRuleFields(rule *AlertRule) error {
 func validateRecordingRuleFields(rule *AlertRule) error {
 	metricName := prommodels.LabelValue(rule.Record.Metric)
 	if !metricName.IsValid() {
-		return fmt.Errorf("%w: %s", ErrAlertRuleFailedValidation, "metric name for recording rule must be a valid utf8 string")
+		return errors.New("metric name for recording rule must be a valid utf8 string")
 	}
 	if !prommodels.IsValidMetricName(metricName) {
-		return fmt.Errorf("%w: %s", ErrAlertRuleFailedValidation, "metric name for recording rule must be a valid Prometheus metric name")
+		return errors.New("metric name for recording rule must be a valid Prometheus metric name")
 	}
 
 	ClearRecordingRuleIgnoredFields(rule)

pkg/services/ngalert/models/alert_rule_test.go

@@ -18,6 +18,7 @@ import (
 	"golang.org/x/exp/maps"
 	"gopkg.in/yaml.v3"
 
+	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/util"
 	"github.com/grafana/grafana/pkg/util/cmputil"
 )
@@ -1018,6 +1019,53 @@ func TestGeneratorFillsAllFields(t *testing.T) {
 	require.FailNow(t, "AlertRule generator does not populate fields", "skipped fields: %v", maps.Keys(fields))
 }
 
+func TestValidateAlertRule(t *testing.T) {
+	t.Run("ExecErrState & NoDataState", func(t *testing.T) {
+		testCases := []struct {
+			name         string
+			execErrState string
+			noDataState  string
+			error        bool
+		}{
+			{
+				name:         "invalid error state",
+				execErrState: "invalid",
+				error:        true,
+			},
+			{
+				name:        "invalid no data state",
+				noDataState: "invalid",
+				error:       true,
+			},
+			{
+				name:  "valid states",
+				error: false,
+			},
+		}
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				rule := RuleGen.With(
+					RuleMuts.WithIntervalSeconds(10),
+				).Generate()
+				if tc.execErrState != "" {
+					rule.ExecErrState = ExecutionErrorState(tc.execErrState)
+				}
+				if tc.noDataState != "" {
+					rule.NoDataState = NoDataState(tc.noDataState)
+				}
+
+				err := rule.ValidateAlertRule(setting.UnifiedAlertingSettings{BaseInterval: 10 * time.Second})
+				if tc.error {
+					require.Error(t, err)
+					require.ErrorIs(t, err, ErrAlertRuleFailedValidation)
+				} else {
+					require.NoError(t, err)
+				}
+			})
+		}
+	})
+}
+
 func TestAlertRule_PrometheusRuleDefinition(t *testing.T) {
 	tests := []struct {
 		name             string