From 1cdadf452135c872eca21795197be47a40ea1ba6 Mon Sep 17 00:00:00 2001
From: Adam Pippin <adam@label-engine.com>
Date: Sun, 14 Feb 2021 17:24:56 -0800
Subject: [PATCH] Have dependency graph throw an exception rather than return
 nothing when no edge nodes are present

---
 app/Util/DependencyGraph.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/app/Util/DependencyGraph.php b/app/Util/DependencyGraph.php
index f88e24d..f675467 100644
--- a/app/Util/DependencyGraph.php
+++ b/app/Util/DependencyGraph.php
@@ -105,6 +105,11 @@ class DependencyGraph
 			}
 		}
 
+		if (sizeof($state) == 0)
+		{
+			throw new \Exception('Cannot solve dependency graph -- no edge nodes. Circular dependency?');
+		}
+
 		// Then walk through the array and insert each node's dependencies before
 		// it recursively.
 		$iter = 0;