Alerting: Clean up join errors code (#106243)

pkg/services/ngalert/state/historian/multiple.go

@@ -2,6 +2,7 @@ package historian
 
 import (
 	"context"
+	"errors"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 	ngmodels "github.com/grafana/grafana/pkg/services/ngalert/models"
@@ -44,7 +45,7 @@ func (h *MultipleBackend) Record(ctx context.Context, rule history_model.RuleMet
 				errs = append(errs, err)
 			}
 		}
-		errCh <- Join(errs...)
+		errCh <- errors.Join(errs...)
 	}()
 	return errCh
 }
@@ -52,53 +53,3 @@ func (h *MultipleBackend) Record(ctx context.Context, rule history_model.RuleMet
 func (h *MultipleBackend) Query(ctx context.Context, query ngmodels.HistoryQuery) (*data.Frame, error) {
 	return h.primary.Query(ctx, query)
 }
-
-// TODO: This is vendored verbatim from the Go standard library.
-// TODO: The grafana project doesn't support go 1.20 yet, so we can't use errors.Join() directly.
-// TODO: Remove this and replace calls with "errors.Join(...)" when go 1.20 becomes the minimum supported version.
-//
-// Join returns an error that wraps the given errors.
-// Any nil error values are discarded.
-// Join returns nil if errs contains no non-nil values.
-// The error formats as the concatenation of the strings obtained
-// by calling the Error method of each element of errs, with a newline
-// between each string.
-func Join(errs ...error) error {
-	n := 0
-	for _, err := range errs {
-		if err != nil {
-			n++
-		}
-	}
-	if n == 0 {
-		return nil
-	}
-	e := &joinError{
-		errs: make([]error, 0, n),
-	}
-	for _, err := range errs {
-		if err != nil {
-			e.errs = append(e.errs, err)
-		}
-	}
-	return e
-}
-
-type joinError struct {
-	errs []error
-}
-
-func (e *joinError) Error() string {
-	var b []byte
-	for i, err := range e.errs {
-		if i > 0 {
-			b = append(b, '\n')
-		}
-		b = append(b, err.Error()...)
-	}
-	return string(b)
-}
-
-func (e *joinError) Unwrap() []error {
-	return e.errs
-}