git-debrebase: bomb on totally ambiguous pseudomerges

[dgit.git] / git-debrebase

diff --git a/git-debrebase b/git-debrebase
index 0e199b852a747d3e9d225a69d8d5bca0a1003ee5..b69450baaa4f952463e6bbcb925ad0be6a0788e1 100755 (executable)
--- a/git-debrebase
+++ b/git-debrebase
@@ -33,7 +33,7 @@
 #    git-debrebase [<options>] stitch [--prose=<for commit message>]
 #    git-debrebase [<options>] downstream-rebase-launder-v0  # experimental
 #
-#    git-debrebase [<options>] convert-from-gbp <upstream-git-rev>
+#    git-debrebase [<options>] convert-from-gbp [<upstream-git-rev>]
 #    git-debrebase [<options>] convert-to-gbp
 
 # problems / outstanding questions:
@@ -450,15 +450,23 @@ sub classify ($) {
                           Contributor => $identical[0]);
     }
     if (@p == 2 && @identical == 2) {
-       my @bytime = nsort_by {
-           my ($ph,$pm) = get_commit $_->{CommitId};
+       my $get_t = sub {
+           my ($ph,$pm) = get_commit $_[0]{CommitId};
            $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
            $1;
-       } @p;
+       };
+       my @bytime = @p;
+       my $order = $get_t->($bytime[0]) <=> $get_t->($bytime[1]);
+       if ($order > 0) { # newer first
+       } elsif ($order < 0) {
+           @bytime = reverse @bytime;
+       } else {
+           return $unknown->('merge of two identical same-age parents');
+       }
        return $classify->(qw(Pseudomerge),
                           SubType => qw(Ambiguous),
-                          Overwritten => [ $bytime[0] ],
-                          Contributor => $bytime[1]);
+                          Contributor => $bytime[0],
+                          Overwritten => [ $bytime[1] ]);
     }
     foreach my $p (@p) {
        my ($p_h, $p_m) = get_commit $p->{CommitId};