ignore DNS error when doing migration allow/block check (#19567)

Co-authored-by: Lauris BH <lauris@nix.lv>

models/error.go

@@ -332,7 +332,6 @@ type ErrInvalidCloneAddr struct {
 	IsProtocolInvalid  bool
 	IsPermissionDenied bool
 	LocalPath          bool
-	NotResolvedIP      bool
 }
 
 // IsErrInvalidCloneAddr checks if an error is a ErrInvalidCloneAddr.
@@ -342,9 +341,6 @@ func IsErrInvalidCloneAddr(err error) bool {
 }
 
 func (err *ErrInvalidCloneAddr) Error() string {
-	if err.NotResolvedIP {
-		return fmt.Sprintf("migration/cloning from '%s' is not allowed: unknown hostname", err.Host)
-	}
 	if err.IsInvalidPath {
 		return fmt.Sprintf("migration/cloning from '%s' is not allowed: the provided path is invalid", err.Host)
 	}

services/migrations/migrate.go

@@ -81,10 +81,9 @@ func IsMigrateURLAllowed(remoteURL string, doer *user_model.User) error {
 		err = nil //nolint
 		hostName = u.Host
 	}
-	addrList, err := net.LookupIP(hostName)
-	if err != nil {
-		return &models.ErrInvalidCloneAddr{Host: u.Host, NotResolvedIP: true}
-	}
+
+	// some users only use proxy, there is no DNS resolver. it's safe to ignore the LookupIP error
+	addrList, _ := net.LookupIP(hostName)
 
 	var ipAllowed bool
 	var ipBlocked bool