From 67c2b502dda8b651aa5cbf6c85755a844492ec79 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Fri, 8 Nov 2019 12:22:00 +0100
Subject: [PATCH] allocate ModuleGraphConnections.explanations only when needed

---
 lib/ModuleGraphConnection.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/ModuleGraphConnection.js b/lib/ModuleGraphConnection.js
index 15f34d852..97f0ba0e2 100644
--- a/lib/ModuleGraphConnection.js
+++ b/lib/ModuleGraphConnection.js
@@ -36,8 +36,9 @@ class ModuleGraphConnection {
 		/** @type {function(): boolean} */
 		this.condition = condition;
 		/** @type {Set<string>} */
-		this.explanations = new Set();
+		this.explanations = undefined;
 		if (explanation) {
+			this.explanations = new Set();
 			this.explanations.add(explanation);
 		}
 	}
@@ -61,10 +62,14 @@ class ModuleGraphConnection {
 	 * @returns {void}
 	 */
 	addExplanation(explanation) {
+		if (this.explanations === undefined) {
+			this.explanations = new Set();
+		}
 		this.explanations.add(explanation);
 	}
 
 	get explanation() {
+		if (this.explanations === undefined) return "";
 		return Array.from(this.explanations).join(" ");
 	}