Chore: Replace go-multierror with errors package (#66432)

* code refactor and type assertions added to tests

* no-lint rule added for specific line

pkg/services/ngalert/state/cache.go

@@ -2,6 +2,7 @@ package state
 
 import (
 	"context"
+	"errors"
 	"math"
 	"net/url"
 	"strings"
@@ -9,7 +10,6 @@ import (
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
-	"github.com/hashicorp/go-multierror"
 
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/services/ngalert/eval"
@@ -161,21 +161,21 @@ func calculateState(ctx context.Context, log log.Logger, alertRule *ngModels.Ale
 // template.ExpandError errors.
 func expand(ctx context.Context, log log.Logger, name string, original map[string]string, data template.Data, externalURL *url.URL, evaluatedAt time.Time) (map[string]string, error) {
 	var (
-		errs     *multierror.Error
+		errs     error
 		expanded = make(map[string]string, len(original))
 	)
 	for k, v := range original {
 		result, err := template.Expand(ctx, name, v, data, externalURL, evaluatedAt)
 		if err != nil {
 			log.Error("Error in expanding template", "error", err)
-			errs = multierror.Append(errs, err)
+			errs = errors.Join(errs, err)
 			// keep the original template on error
 			expanded[k] = v
 		} else {
 			expanded[k] = result
 		}
 	}
-	return expanded, errs.ErrorOrNil()
+	return expanded, errs
 }
 
 func (rs *ruleStates) deleteStates(predicate func(s *State) bool) []*State {

pkg/services/ngalert/state/cache_test.go

@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
-	"github.com/hashicorp/go-multierror"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -67,14 +66,15 @@ func Test_expand(t *testing.T) {
 		require.NotNil(t, err)
 		require.Equal(t, original, results)
 
-		// TODO: Please update this test in issue https://github.com/grafana/grafana/issues/63686
-		var multierr *multierror.Error
-		require.True(t, errors.As(err, &multierr))
-		require.Equal(t, multierr.Len(), 2)
+		//nolint:errorlint
+		multierr, is := err.(interface{ Unwrap() []error })
+		require.True(t, is)
+		unwrappedErrors := multierr.Unwrap()
+		require.Equal(t, len(unwrappedErrors), 2)
 
 		errsStr := []string{
-			multierr.Errors[0].Error(),
-			multierr.Errors[1].Error(),
+			unwrappedErrors[0].Error(),
+			unwrappedErrors[1].Error(),
 		}
 
 		firstErrStr := "failed to expand template '{{- $labels := .Labels -}}{{- $values := .Values -}}{{- $value := .Value -}}Instance {{ $labels. }} has been down for more than 5 minutes': error parsing template __alert_test: template: __alert_test:1: unexpected <.> in operand"
@@ -83,7 +83,7 @@ func Test_expand(t *testing.T) {
 		require.Contains(t, errsStr, firstErrStr)
 		require.Contains(t, errsStr, secondErrStr)
 
-		for _, err := range multierr.Errors {
+		for _, err := range unwrappedErrors {
 			var expandErr template.ExpandError
 			require.True(t, errors.As(err, &expandErr))
 		}
@@ -103,10 +103,11 @@ func Test_expand(t *testing.T) {
 		require.NotNil(t, err)
 		require.Equal(t, expected, results)
 
-		// TODO: Please update this test in issue https://github.com/grafana/grafana/issues/63686
-		var multierr *multierror.Error
-		require.True(t, errors.As(err, &multierr))
-		require.Equal(t, multierr.Len(), 1)
+		//nolint:errorlint
+		multierr, is := err.(interface{ Unwrap() []error })
+		require.True(t, is)
+		unwrappedErrors := multierr.Unwrap()
+		require.Equal(t, len(unwrappedErrors), 1)
 
 		// assert each error matches the expected error
 		var expandErr template.ExpandError