fi-prune-empty: Whoops, some merges weren't being pruned

If 2 parents both mapped to the same commit, it would emit a commit with 2
of the same parent, bypassing the no-change logic.

1 files changed, 9 insertions, 1 deletions

diff --git a/fi-prune-empty/main.go b/fi-prune-empty/main.go
index 7c1ea5d..fb25794 100644
--- a/fi-prune-empty/main.go
+++ b/fi-prune-empty/main.go
@@ -149,11 +149,19 @@ func (h *PruneEmpty) subsumedBy(c string, commits []string) bool {
 	}
 	return false
 }
+func inArray(needle string, haystack []string) bool {
+	for _, straw := range haystack {
+		if straw == needle {
+			return true
+		}
+	}
+	return false
+}
 func (h *PruneEmpty) pruneParents(commits []string) []string {
 	var ret []string
 	for _, c := range commits {
 		c = h.fixupMark(c)
-		if c != "" && !h.subsumedBy(c, commits) {
+		if c != "" && !h.subsumedBy(c, commits) && !inArray(c, ret) {
 			ret = append(ret, c)
 		}
 	}