git-debrebase: merge: Save wreckage if desired

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

diff --git a/git-debrebase b/git-debrebase
index abf9157e0554fbf7e9496c030af64c9c919fe3cc..589fa901af95f5b1158f850b205e9defc20331ac 100755 (executable)
--- a/git-debrebase
+++ b/git-debrebase
@@ -51,10 +51,12 @@ See git-debrebase(1), git-debrebase(5), dgit-maint-debrebase(7) (in dgit).
 END
 
 our ($opt_force, $opt_noop_ok, @opt_anchors);
-our ($opt_defaultcmd_interactive);
+our ($opt_defaultcmd_interactive, $opt_save_wreckage);
 
 our $us = qw(git-debrebase);
 
+our $wrecknoteprefix = 'refs/debrebase-wreckage';
+
 $|=1;
 
 sub badusage ($) {
@@ -373,6 +375,25 @@ sub merge_failed ($$) {
     my @m;
     push @m, "Merge resolution failed: $emsg";
 
+    $opt_save_wreckage //= do {
+       my $c = cfg 'git-debrebase.merge.save-wreckage', 1;
+       # ^ xxx documentation
+       $c && $c =~ m/^[1ty]/;
+    };
+
+    if ($opt_save_wreckage) {
+       my @updates;
+       git_for_each_ref("$wrecknoteprefix/*", sub {
+            my ($objid,$objtype,$fullrefname,$reftail) = @_;
+            push @updates, "delete $fullrefname";
+        });
+       keys %$wrecknotes;
+       while (my ($k,$v) = each %$wrecknotes) {
+           push @updates, "create $wrecknoteprefix/$k $v";
+       }
+       run_ref_updates_now "merge failed", \@updates;
+       push @m, "Wreckage left in $wrecknoteprefix/* as requested.";
+    }
     push @m, "See git-debrebase(1) section FAILED MERGES for suggestions.";
     # ^ xxx this section does not yet exist
     fail join '', map { "$_\n" } @m;
@@ -2608,6 +2629,7 @@ getoptions_main
           'anchor=s' => \@opt_anchors,
           '--dgit=s' => \($dgit[0]),
           'force!',
+          '--save-wreckage', \$opt_save_wreckage,
           '-i:s' => sub {
               my ($opt,$val) = @_;
               badusage "git-debrebase: no cuddling to -i for git-rebase"