git-debrebase: merge: Prettify subprocess failures

If we print STDERR in advance, there is a newline beforehand, which is
undesirable.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

1 files changed, 6 insertions, 4 deletions

diff --git a/git-debrebase b/git-debrebase
index d3ed731..7f96749 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -379,10 +379,11 @@ sub gbp_pq_export ($$$) {
 #  our own patch identification algorithm?
 #  this is an alternative strategy
 
-sub merge_failed ($$) {
-    my ($wrecknotes, $emsg) = @_;
+sub merge_failed ($$;@) {
+    my ($wrecknotes, $emsg, @xmsgs) = @_;
     my @m;
     push @m, "Merge resolution failed: $emsg";
+    push @m, @xmsgs;
 
     changedir $maindir;
 
@@ -443,8 +444,9 @@ sub merge_series ($$$;@) {
 	debugcmd '+', @_;
 	$!=0; $?=-1;
 	if (system @_) {
-	    failedcmd_report_cmd undef, @_;
-	    merge_failed $wrecknotes, failedcmd_waitstatus();
+	    merge_failed $wrecknotes,
+		failedcmd_waitstatus(),
+		"failed command: @_";
 	}
     };