Make CSSConditionRule.conditionText readonly.

emilio · moz-wptsync-bot · commit d2bf5dfe928e · 2022-04-12T05:19:08.000+01:00
Differential Revision: https://phabricator.services.mozilla.com/D143193 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1762474 gecko-commit: 99a576b867673ace7c940451a070a0c3a8e7629b gecko-reviewers: layout-reviewers, firefox-style-system-reviewers, boris
diff --git a/css/cssom/CSSConditionRule-conditionText.html b/css/cssom/CSSConditionRule-conditionText.html
@@ -0,0 +1,23 @@
+<!doctype html>
+<title>CSSConditionRule.conditionText</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://drafts.csswg.org/css-conditional-3/#cssconditionrule">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+@media not all {
+  :root { color: lime }
+}
+</style>
+<script>
+test(function(t) {
+  let rule = document.styleSheets[0].cssRules[0];
+  assert_true(rule instanceof CSSConditionRule);
+  assert_equals(rule.conditionText, "not all");
+  rule.conditionText = 1;
+  assert_equals(rule.conditionText, "not all");
+  rule.conditionText = "all";
+  assert_equals(rule.conditionText, "not all");
+  assert_not_equals(getComputedStyle(document.documentElement).color, "rgb(0, 255, 0)");
+});
+</script>
diff --git a/interfaces/css-conditional.idl b/interfaces/css-conditional.idl
@@ -9,7 +9,7 @@ partial interface CSSRule {
 
 [Exposed=Window]
 interface CSSConditionRule : CSSGroupingRule {
-    attribute CSSOMString conditionText;
+    readonly attribute CSSOMString conditionText;
 };
 
 [Exposed=Window]
