From a3d157bde6970567605d499d2780b603c76b1239 Mon Sep 17 00:00:00 2001
From: James Shubin <james@shubin.ca>
Date: Tue, 20 Dec 2016 05:15:57 -0500
Subject: [PATCH] pgraph: Mutex must be a pointer

This should be done the same way as the WaitGroup so that we don't
panic!
---
 pgraph/pgraph.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pgraph/pgraph.go b/pgraph/pgraph.go
index 3a464f4a..d698f139 100644
--- a/pgraph/pgraph.go
+++ b/pgraph/pgraph.go
@@ -79,8 +79,9 @@ func NewGraph(name string) *Graph {
 		Name:      name,
 		Adjacency: make(map[*Vertex]map[*Vertex]*Edge),
 		state:     graphStateNil,
-		// ptr b/c: "A WaitGroup must not be copied after first use."
-		wg: &sync.WaitGroup{},
+		// ptr b/c: Mutex/WaitGroup must not be copied after first use
+		mutex: &sync.Mutex{},
+		wg:    &sync.WaitGroup{},
 	}
 }