From 5a1cc3fa8fb701b13009c9fd2d9c35295a061d8c Mon Sep 17 00:00:00 2001
From: Tom Wilkie <tom.wilkie@gmail.com>
Date: Mon, 30 Nov 2015 12:43:02 +0000
Subject: [PATCH] Filter nodes that are only connected to themselves.

---
 render/filters.go      | 11 +++++++----
 render/filters_test.go | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/render/filters.go b/render/filters.go
index 84711d1771..9bacd0c3dc 100644
--- a/render/filters.go
+++ b/render/filters.go
@@ -22,7 +22,8 @@ func (c CustomRenderer) Render(rpt report.Report) RenderableNodes {
 }
 
 // ColorConnected colors nodes with the IsConnected key if
-// they have edges to or from them.
+// they have edges to or from them.  Edges to/from yourself
+// are not counted here (see #656).
 func ColorConnected(r Renderer) Renderer {
 	return CustomRenderer{
 		Renderer: r,
@@ -35,9 +36,11 @@ func ColorConnected(r Renderer) Renderer {
 					continue
 				}
 
-				connected[id] = void
-				for _, id := range node.Adjacency {
-					connected[id] = void
+				for _, adj := range node.Adjacency {
+					if adj != id {
+						connected[id] = void
+						connected[adj] = void
+					}
 				}
 			}
 
diff --git a/render/filters_test.go b/render/filters_test.go
index 905fea177f..325e29d25d 100644
--- a/render/filters_test.go
+++ b/render/filters_test.go
@@ -108,3 +108,18 @@ func TestFilterUnconnectedPesudoNodes(t *testing.T) {
 		}
 	}
 }
+
+func TestFilterUnconnectedSelf(t *testing.T) {
+	// Test nodes that are only connected to themselves are filtered.
+	{
+		nodes := render.RenderableNodes{
+			"foo": {ID: "foo", Node: report.MakeNode().WithAdjacent("foo")},
+		}
+		renderer := render.FilterUnconnected(mockRenderer{RenderableNodes: nodes})
+		want := render.RenderableNodes{}
+		have := renderer.Render(report.MakeReport()).Prune()
+		if !reflect.DeepEqual(want, have) {
+			t.Error(test.Diff(want, have))
+		}
+	}
+}