From: Mathis Beer <Mathis.Beer@funkwerk-itk.com>
Date: Thu, 12 Mar 2020 10:20:59 +0000 (+0100)
Subject: Work around issue 1671: avoid creating a virtual edge loop.
X-Git-Tag: stable_release_2.44.0~10^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=549c7725b043c03cf62dae3acc0509350d03cd7b;p=graphviz

Work around issue 1671: avoid creating a virtual edge loop.
Not an actual solution!
The code removed from flat_rev is already done in merge_oneway.
---

diff --git a/lib/dotgen/fastgr.c b/lib/dotgen/fastgr.c
index 03d0396b1..ecfc201f0 100644
--- a/lib/dotgen/fastgr.c
+++ b/lib/dotgen/fastgr.c
@@ -338,7 +338,7 @@ basic_merge(edge_t * e, edge_t * rep)
 void 
 merge_oneway(edge_t * e, edge_t * rep)
 {
-    if (rep == ED_to_virt(e)) {
+    if (rep == ED_to_virt(e) || e == ED_to_virt(rep)) {
 	agerr(AGWARN, "merge_oneway glitch\n");
 	return;
     }
diff --git a/lib/dotgen/mincross.c b/lib/dotgen/mincross.c
index d15616683..c7c498541 100644
--- a/lib/dotgen/mincross.c
+++ b/lib/dotgen/mincross.c
@@ -1213,8 +1213,6 @@ void flat_rev(Agraph_t * g, Agedge_t * e)
 		break;
     if (rev) {
 	merge_oneway(e, rev);
-	if (ED_to_virt(e) == 0)
-	    ED_to_virt(e) = rev;
 	if ((ED_edge_type(rev) == FLATORDER)
 	    && (ED_to_orig(rev) == 0))
 	    ED_to_orig(rev) = e;