X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=git-debrebase;h=2a28e720b43d3712fb2910902375fb5113e6370b;hp=37982499351e8365da2ef022c71f9abff5873b29;hb=952a781025083b34762fe6bb2093ef64524c23cd;hpb=a7e1b2feb9013251c5d1c763394170acc95eef65

diff --git a/git-debrebase b/git-debrebase
index 37982499..2a28e720 100755
--- 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 ($) {
@@ -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;
 
@@ -368,8 +379,36 @@ sub gbp_pq_export ($$$) {
 #  our own patch identification algorithm?
 #  this is an alternative strategy
 
+sub merge_failed ($$) {
+    my ($wrecknotes, $emsg) = @_;
+    my @m;
+    push @m, "Merge resolution failed: $emsg";
+
+    $opt_save_wreckage //= do {
+	my $c = cfg 'git-debrebase.merge.save-wreckage', 1;
+	# ^ xxx documentation
+	$c && $c =~ m/^[1ty]/;
+    };
+
+    if ($opt_save_wreckage) {
+	my @updates;
+	merge_wreckage_cleaning \@updates;
+	keys %$wrecknotes;
+	while (my ($k,$v) = each %$wrecknotes) {
+	    push @updates, "create $wrecknoteprefix/$k $v";
+	}
+	run_ref_updates_now "merge failed", \@updates;
+	push @m, "Wreckage left in $wrecknoteprefix/* as requested.";
+    }
+    push @m, "See git-debrebase(1) section FAILED MERGES for suggestions.";
+    # ^ xxx this section does not yet exist
+    fail join '', map { "$_\n" } @m;
+}
+
 sub mwrecknote ($$$) {
     my ($wrecknotes, $reftail, $commitish) = @_;
+    confess unless defined $commitish;
+    printdebug "mwrecknote $reftail $commitish\n";
     $wrecknotes->{$reftail} = $commitish;
 }
 
@@ -454,7 +493,7 @@ sub merge_series ($$$;@) {
 	    printdebug "pec' $pec\n";
             runcmd @git, qw(reset -q --hard), $pec;
 	    $q->{MR}{PEC} = $pec;
-	    $mwrecknote->("$q->{LeftRight}-patchqueue");
+	    $mwrecknote->("$q->{LeftRight}-patchqueue", $pec);
 	}
 	# now, because of reverse, we are on $input_q->{MR}{OQC}
 	runcmd @git, qw(checkout -q -b merge);
@@ -1044,7 +1083,8 @@ sub walk ($;$$$) {
     };
 
     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}, @_); };
@@ -1053,6 +1093,7 @@ sub walk ($;$$$) {
 
     for (;;) {
 	$cl = classify $cur;
+	$cl->{MergeWreckNotes} //= {};
 	my $ty = $cl->{Type};
 	my $st = $cl->{SubType};
 	$prline->("$cl->{CommitId} $cl->{Type}");
@@ -2594,6 +2635,7 @@ 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"