From c2332ce4aa35d3555e536fcac10201919955e267 Mon Sep 17 00:00:00 2001
From: subwaystation <simon.heumos@qbic.uni-tuebingen.de>
Date: Tue, 6 Oct 2020 15:14:22 +0200
Subject: [PATCH] handle reversing self edges in divide_handle in odgi

---
 bdsg/src/odgi.cpp         | 16 ++++++++++++++++
 bdsg/src/test_libbdsg.cpp |  4 ++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/bdsg/src/odgi.cpp b/bdsg/src/odgi.cpp
index 030cbb51..fcd3dd5f 100644
--- a/bdsg/src/odgi.cpp
+++ b/bdsg/src/odgi.cpp
@@ -1131,6 +1131,22 @@ std::vector<handle_t> ODGI::divide_handle(const handle_t& handle, const std::vec
     for (auto& s : seqs) {
         handles.push_back(create_handle(s));
     }
+
+    // update the backwards references back onto this node
+    handle_t last_handle = handles.back();
+    follow_edges(fwd_handle, false, [&](const handle_t& h) {
+            if (h == flip(fwd_handle)) {
+                // destroy_edge(last_handle, h);
+                create_edge(last_handle, flip(handles.back()));
+            }
+    });
+    // update the forward references back onto this node
+    follow_edges(handle, left, [&](const handle_t& h) {
+        if (h == flip(handle)) {
+            create_edge(h, handles.front());
+        }
+    });
+
     // and record their reverse, for use in path fixup
     std::vector<handle_t> rev_handles;
     for (auto& h : handles) {
diff --git a/bdsg/src/test_libbdsg.cpp b/bdsg/src/test_libbdsg.cpp
index b9173175..63b90243 100644
--- a/bdsg/src/test_libbdsg.cpp
+++ b/bdsg/src/test_libbdsg.cpp
@@ -1357,8 +1357,8 @@ void test_deletable_handle_graphs() {
         PackedGraph pg;
         implementations.push_back(&pg);
         
-        //ODGI og;
-        //implementations.push_back(&og);
+        ODGI og;
+        implementations.push_back(&og);
         
         for (DeletableHandleGraph* implementation : implementations) {
             DeletableHandleGraph& graph = *implementation;