fix(alerts): surface individual validation errors in API response

pkg/types/ruletypes/api_params.go

@@ -338,6 +338,7 @@ func isValidLabelValue(v string) bool {
 // validate runs during UnmarshalJSON (read + write path).
 // Preserves the original pre-existing checks only so that stored rules
 // continue to load without errors.
+// TODO(srikanthccv): remove this once v1 is deprecated and removed
 func (r *PostableRule) validate() error {
 	var errs []error
 
@@ -366,9 +367,13 @@ func (r *PostableRule) validate() error {
 
 	errs = append(errs, testTemplateParsing(r)...)
 
-	joined := errors.Join(errs...)
-	if joined != nil {
-		return errors.WrapInvalidInputf(joined, errors.CodeInvalidInput, "validation failed")
+	if len(errs) > 0 {
+		messages := make([]string, len(errs))
+		for i, e := range errs {
+			messages[i] = e.Error()
+		}
+		return errors.NewInvalidInputf(errors.CodeInvalidInput, "alert rule definition is not valid").
+			WithAdditional(messages...)
 	}
 	return nil
 }
@@ -466,9 +471,13 @@ func (r *PostableRule) Validate() error {
 
 	errs = append(errs, testTemplateParsing(r)...)
 
-	joined := errors.Join(errs...)
-	if joined != nil {
-		return errors.WrapInvalidInputf(joined, errors.CodeInvalidInput, "validation failed")
+	if len(errs) > 0 {
+		messages := make([]string, len(errs))
+		for i, e := range errs {
+			messages[i] = e.Error()
+		}
+		return errors.NewInvalidInputf(errors.CodeInvalidInput, "alert rule is not valid").
+			WithAdditional(messages...)
 	}
 	return nil
 }

pkg/types/ruletypes/validate_test.go

@@ -4,8 +4,23 @@ import (
 	"encoding/json"
 	"strings"
 	"testing"
+
+	"github.com/SigNoz/signoz/pkg/errors"
 )
 
+func errorContains(err error, substr string) bool {
+	j := errors.AsJSON(err)
+	if strings.Contains(j.Message, substr) {
+		return true
+	}
+	for _, e := range j.Errors {
+		if strings.Contains(e.Message, substr) {
+			return true
+		}
+	}
+	return false
+}
+
 // validV1Builder returns a minimal valid v1 builder rule JSON.
 func validV1Builder() string {
 	return `{
@@ -494,7 +509,7 @@ func TestValidate_PostableRule_Common(t *testing.T) {
 			if tt.wantErr {
 				if err == nil {
 					t.Errorf("expected error containing %q, got nil", tt.errSubstr)
-				} else if tt.errSubstr != "" && !strings.Contains(err.Error(), tt.errSubstr) {
+				} else if tt.errSubstr != "" && !errorContains(err, tt.errSubstr) {
 					t.Errorf("expected error containing %q, got: %v", tt.errSubstr, err)
 				}
 			} else {
@@ -687,7 +702,7 @@ func TestValidate_V1_ConditionFields(t *testing.T) {
 			if tt.wantErr {
 				if validateErr == nil {
 					t.Errorf("expected Validate() error containing %q, got nil", tt.errSubstr)
-				} else if tt.errSubstr != "" && !strings.Contains(validateErr.Error(), tt.errSubstr) {
+				} else if tt.errSubstr != "" && !errorContains(validateErr, tt.errSubstr) {
 					t.Errorf("expected error containing %q, got: %v", tt.errSubstr, validateErr)
 				}
 			} else {
@@ -1029,7 +1044,7 @@ func TestValidate_V2Alpha1(t *testing.T) {
 			if tt.wantErr {
 				if err == nil {
 					t.Errorf("expected error containing %q, got nil", tt.errSubstr)
-				} else if tt.errSubstr != "" && !strings.Contains(err.Error(), tt.errSubstr) {
+				} else if tt.errSubstr != "" && !errorContains(err, tt.errSubstr) {
 					t.Errorf("expected error containing %q, got: %v", tt.errSubstr, err)
 				}
 			} else {
@@ -1337,7 +1352,7 @@ func TestValidate_MultipleErrors(t *testing.T) {
 			t.Fatal("expected unmarshal error for wrong version")
 		}
 		// The error should mention version
-		if !strings.Contains(err.Error(), "version") {
+		if !errorContains(err, "version") {
 			t.Errorf("expected error to mention version, got: %v", err)
 		}
 	})
@@ -1355,10 +1370,9 @@ func TestValidate_MultipleErrors(t *testing.T) {
 		if validateErr == nil {
 			t.Fatal("expected Validate() error")
 		}
-		errStr := validateErr.Error()
 		// Should contain errors for thresholds, evaluation, notificationSettings
 		for _, substr := range []string{"evaluation", "notificationSettings"} {
-			if !strings.Contains(errStr, substr) {
+			if !errorContains(validateErr, substr) {
 				t.Errorf("expected error to mention %q, got: %v", substr, validateErr)
 			}
 		}
@@ -1469,7 +1483,7 @@ func TestValidate_V2Alpha1_CumulativeEvaluation(t *testing.T) {
 			if tt.wantErr {
 				if err == nil {
 					t.Errorf("expected error containing %q, got nil", tt.errSubstr)
-				} else if !strings.Contains(err.Error(), tt.errSubstr) {
+				} else if !errorContains(err, tt.errSubstr) {
 					t.Errorf("expected error containing %q, got: %v", tt.errSubstr, err)
 				}
 			} else if err != nil {