From 5382a99adb00a77e8b25fc246b3213616a471f79 Mon Sep 17 00:00:00 2001
From: Mats Palmgren <mats@mozilla.com>
Date: Tue, 21 Jul 2020 19:46:45 +0000
Subject: [PATCH] style: [css-grid] Make empty and all-whitespace strings in
 'grid-template-areas' invalid.

Differential Revision: https://phabricator.services.mozilla.com/D84398
---
 components/style/values/specified/position.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/components/style/values/specified/position.rs b/components/style/values/specified/position.rs
index 72886b2d7b1..1b55e010878 100644
--- a/components/style/values/specified/position.rs
+++ b/components/style/values/specified/position.rs
@@ -710,6 +710,11 @@ impl TemplateAreas {
                     });
                     current_area_index = Some(index);
                 }
+                if column == 0 {
+                    // Each string must produce a valid token.
+                    // https://github.com/w3c/csswg-drafts/issues/5110
+                    return Err(());
+                }
                 if let Some(index) = current_area_index {
                     if areas[index].columns.end != column + 1 {
                         assert_ne!(areas[index].rows.start, row);