Issue #2078 - Follow-up: Ensure empty selector lists aren't iterated when serialized

Really odd that this wasn't caught/doesn't cause any issues on MSVC/unoptimized GCC. Must've been luck, I guess.

1 files changed, 4 insertions, 0 deletions

diff --git a/layout/style/StyleRule.cpp b/layout/style/StyleRule.cpp
index 815c6f96cc..437806a1b8 100644
--- a/layout/style/StyleRule.cpp
+++ b/layout/style/StyleRule.cpp
@@ -1030,6 +1030,10 @@ nsCSSSelectorList::ToString(nsAString& aResult, CSSStyleSheet* aSheet)
 {
   aResult.Truncate();
   nsCSSSelectorList *p = this;
+  // Don't append anything if we're an empty selector list.
+  if (!mSelectors) {
+    return;
+  }
   for (;;) {
     p->mSelectors->ToString(aResult, aSheet, true);
     p = p->mNext;