From 51a3972ad573f658a96548e593b4665b82ec0863 Mon Sep 17 00:00:00 2001
From: Jacob Wright <jacwright@gmail.com>
Date: Wed, 19 Sep 2018 15:23:01 -0600
Subject: [PATCH] Fixes shorthand class directives which do not have classes

Fixes #1739
---
 src/compile/nodes/Element.ts                     |  2 +-
 .../samples/class-shortcut-with-class/_config.js | 16 ++++++++++++++++
 .../samples/class-shortcut-with-class/main.html  |  1 +
 test/runtime/samples/class-shortcut/_config.js   |  7 +++----
 test/runtime/samples/class-shortcut/main.html    |  2 +-
 5 files changed, 22 insertions(+), 6 deletions(-)
 create mode 100644 test/runtime/samples/class-shortcut-with-class/_config.js
 create mode 100644 test/runtime/samples/class-shortcut-with-class/main.html

diff --git a/src/compile/nodes/Element.ts b/src/compile/nodes/Element.ts
index 32f0b04e37..1206ad939b 100644
--- a/src/compile/nodes/Element.ts
+++ b/src/compile/nodes/Element.ts
@@ -1326,7 +1326,7 @@ export default class Element extends Node {
 				dependencies = expression.dependencies;
 			} else {
 				snippet = `ctx${quotePropIfNecessary(name)}`;
-				dependencies = [name];
+				dependencies = new Set([name]);
 			}
 			const updater = `@toggleClass(${this.var}, "${name}", ${snippet});`;
 
diff --git a/test/runtime/samples/class-shortcut-with-class/_config.js b/test/runtime/samples/class-shortcut-with-class/_config.js
new file mode 100644
index 0000000000..2d36b6eabf
--- /dev/null
+++ b/test/runtime/samples/class-shortcut-with-class/_config.js
@@ -0,0 +1,16 @@
+export default {
+	data: {
+		"is-active": true,
+		isSelected: true,
+		myClass: 'one two'
+	},
+	html: `<div class="one two is-active isSelected"></div>`,
+
+	test ( assert, component, target, window ) {
+		component.set({ "is-active": false });
+
+		assert.htmlEqual( target.innerHTML, `
+			<div class="one two isSelected"></div>
+		` );
+	}
+};
diff --git a/test/runtime/samples/class-shortcut-with-class/main.html b/test/runtime/samples/class-shortcut-with-class/main.html
new file mode 100644
index 0000000000..8e608c33e7
--- /dev/null
+++ b/test/runtime/samples/class-shortcut-with-class/main.html
@@ -0,0 +1 @@
+<div class="{ myClass }" class:is-active class:isSelected class:not-used></div>
diff --git a/test/runtime/samples/class-shortcut/_config.js b/test/runtime/samples/class-shortcut/_config.js
index 2d36b6eabf..22ccd68b5b 100644
--- a/test/runtime/samples/class-shortcut/_config.js
+++ b/test/runtime/samples/class-shortcut/_config.js
@@ -1,16 +1,15 @@
 export default {
 	data: {
 		"is-active": true,
-		isSelected: true,
-		myClass: 'one two'
+		isSelected: true
 	},
-	html: `<div class="one two is-active isSelected"></div>`,
+	html: `<div class="is-active isSelected"></div>`,
 
 	test ( assert, component, target, window ) {
 		component.set({ "is-active": false });
 
 		assert.htmlEqual( target.innerHTML, `
-			<div class="one two isSelected"></div>
+			<div class="isSelected"></div>
 		` );
 	}
 };
diff --git a/test/runtime/samples/class-shortcut/main.html b/test/runtime/samples/class-shortcut/main.html
index 8e608c33e7..2bd6a32b6e 100644
--- a/test/runtime/samples/class-shortcut/main.html
+++ b/test/runtime/samples/class-shortcut/main.html
@@ -1 +1 @@
-<div class="{ myClass }" class:is-active class:isSelected class:not-used></div>
+<div class:is-active class:isSelected class:not-used></div>