git-debrebase: merge: Save wreckage in $maindir

[dgit.git] / git-debrebase

diff --git a/git-debrebase b/git-debrebase
index 563fb9970fa4f7bb8f7ac46c4d7b583e8d68f36a..213728023f249305eb873722d305f3168a1cb0c4 100755 (executable)
--- a/git-debrebase
+++ b/git-debrebase
@@ -55,6 +55,8 @@ our ($opt_defaultcmd_interactive);
 
 our $us = qw(git-debrebase);
 
+our $wrecknoteprefix = 'refs/debrebase-wreckage';
+
 $|=1;
 
 sub badusage ($) {
@@ -152,6 +154,14 @@ our $snags_summarised = 0;
 our @deferred_updates;
 our @deferred_update_messages;
 
+sub merge_wreckage_cleaning ($) {
+    my ($updates) = @_;
+    git_for_each_ref("$wrecknoteprefix/*", sub {
+       my ($objid,$objtype,$fullrefname,$reftail) = @_;
+       push @$updates, "delete $fullrefname";
+    });
+}
+
 sub all_snags_summarised () {
     $snags_forced + $snags_tripped == $snags_summarised;
 }
@@ -160,6 +170,7 @@ sub run_deferred_updates ($) {
 
     confess 'dangerous internal error' unless all_snags_summarised();
 
+    merge_wreckage_cleaning \@deferred_updates;
     run_ref_updates_now $mrest, \@deferred_updates;
     print $_, "\n" foreach @deferred_update_messages;
 
@@ -368,9 +379,31 @@ sub gbp_pq_export ($$$) {
 #  our own patch identification algorithm?
 #  this is an alternative strategy
 
+sub merge_failed ($$) {
+    my ($wrecknotes, $emsg) = @_;
+    my @m;
+    push @m, "Merge resolution failed: $emsg";
+
+    changedir $maindir;
+
+    my @updates;
+    merge_wreckage_cleaning \@updates;
+    keys %$wrecknotes;
+    while (my ($k,$v) = each %$wrecknotes) {
+       push @updates, "create $wrecknoteprefix/$k $v";
+    }
+    run_ref_updates_now "merge failed", \@updates;
+    push @m, "Wreckage left in $wrecknoteprefix/*.";
+
+    push @m, "See git-debrebase(1) section FAILED MERGES for suggestions.";
+    # ^ xxx this section does not yet exist
+    fail join '', map { "$_\n" } @m;
+}
+
 sub mwrecknote ($$$) {
     my ($wrecknotes, $reftail, $commitish) = @_;
     confess unless defined $commitish;
+    printdebug "mwrecknote $reftail $commitish\n";
     $wrecknotes->{$reftail} = $commitish;
 }
 
@@ -1045,7 +1078,8 @@ sub walk ($;$$$) {
     };
 
     my $nomerge = sub {
-       fail "something useful about failed merge attempt @_ xxx".Dumper($cl);
+       my ($emsg) = @_;
+       merge_failed $cl->{MergeWreckNotes}, $emsg;
     };
 
     my $mwrecknote = sub { &mwrecknote($cl->{MergeWreckNotes}, @_); };