git-debrebase: merge: mergedbreakwaters_anchor: Check consistency

Check that the result contains all the other anchors.  This is
ensured by walk, and required of VanillaMerges.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/git-debrebase b/git-debrebase
index 35b75cd..bc725fa 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -846,6 +846,8 @@ sub mergedbreakwaters_anchor ($) {
 	$best_anchor = $panchor
 	    if !defined $best_anchor
 	    or is_fast_fwd $best_anchor, $panchor;
+	fail "inconsistent anchors in merged-breakwaters $p->{CommitId}"
+	    unless is_fast_fwd $panchor, $best_anchor;
     }
     return $best_anchor;
 }