From 8455a7f3a1aa83f487745306df0c07c39b6dc803 Mon Sep 17 00:00:00 2001
From: Steven Lambert <2433219+straker@users.noreply.github.com>
Date: Thu, 3 Sep 2020 08:22:21 -0600
Subject: [PATCH] fix(valid-lang): fail when lang attribute contains only
 whitespace (#2504)

---
 lib/checks/language/valid-lang-evaluate.js        | 7 ++++++-
 test/checks/language/valid-lang.js                | 6 ++++++
 test/integration/rules/valid-lang/valid-lang.html | 1 +
 test/integration/rules/valid-lang/valid-lang.json | 2 +-
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/checks/language/valid-lang-evaluate.js b/lib/checks/language/valid-lang-evaluate.js
index 3305d837a5..01897493b1 100644
--- a/lib/checks/language/valid-lang-evaluate.js
+++ b/lib/checks/language/valid-lang-evaluate.js
@@ -1,4 +1,5 @@
 import { validLangs, getBaseLang } from '../../core/utils';
+import { sanitize } from '../../commons/text';
 
 function validLangEvaluate(node, options, virtualNode) {
 	const langs = (options.value ? options.value : validLangs()).map(getBaseLang);
@@ -14,7 +15,11 @@ function validLangEvaluate(node, options, virtualNode) {
 
 		// Edge sets lang to an empty string when xml:lang is set
 		// so we need to ignore empty strings here
-		if (baselangVal !== '' && langs.indexOf(baselangVal) === -1) {
+		if (
+			(baselangVal !== '' && langs.indexOf(baselangVal) === -1) ||
+			// whitespace only lang value is invalid
+			(langVal !== '' && !sanitize(langVal))
+		) {
 			invalid.push(langAttr + '="' + virtualNode.attr(langAttr) + '"');
 		}
 	});
diff --git a/test/checks/language/valid-lang.js b/test/checks/language/valid-lang.js
index 632b587212..e8bffa6e1f 100644
--- a/test/checks/language/valid-lang.js
+++ b/test/checks/language/valid-lang.js
@@ -67,4 +67,10 @@ describe('valid-lang', function() {
 		assert.isTrue(validLangEvaluate.apply(checkContext, params));
 		assert.deepEqual(checkContext._data, ['custom-lang="en_US"']);
 	});
+
+	it('should return true if lang value is just whitespace', function() {
+		var params = checkSetup('<div id="target" lang="  "></div>');
+
+		assert.isTrue(validLangEvaluate.apply(checkContext, params));
+	});
 });
diff --git a/test/integration/rules/valid-lang/valid-lang.html b/test/integration/rules/valid-lang/valid-lang.html
index 73a707e867..0dd98d03bc 100644
--- a/test/integration/rules/valid-lang/valid-lang.html
+++ b/test/integration/rules/valid-lang/valid-lang.html
@@ -8,3 +8,4 @@
 <p lang="gibberish-US" id="fail1">Not English</p>
 <p xml:lang="gibberish-US" id="fail2">Not English</p>
 <p xml:lang="en-US" lang="gibberish-US" id="fail3">Mix</p>
+<p lang=" " id="fail4">English</p>
diff --git a/test/integration/rules/valid-lang/valid-lang.json b/test/integration/rules/valid-lang/valid-lang.json
index 328b10c55f..65b7d71acc 100644
--- a/test/integration/rules/valid-lang/valid-lang.json
+++ b/test/integration/rules/valid-lang/valid-lang.json
@@ -1,7 +1,7 @@
 {
 	"description": "valid-lang test",
 	"rule": "valid-lang",
-	"violations": [["#fail1"], ["#fail2"], ["#fail3"]],
+	"violations": [["#fail1"], ["#fail2"], ["#fail3"], ["#fail4"]],
 	"passes": [
 		["#pass1"],
 		["#pass2"],