confess 'dangerous internal error' unless all_snags_summarised();
- my @upd_cmd = (@git, qw(update-ref --stdin -m), "debrebase: $mrest");
+ my @upd_cmd = (git_update_ref_cmd "debrebase: $mrest", qw(--stdin));
debugcmd '>|', @upd_cmd;
open U, "|-", @upd_cmd or die $!;
foreach (@deferred_updates) {