layout_thread: Avoid adding the UA sheets multiple times when there's…

… no root flow. Fixes #18631
servo · Oct 1, 2017 · 8976b1a · 8976b1a
1 parent dd27ec1
commit 8976b1a
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Showing 3 changed files with 27 additions and 2 deletions.
diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
@@ -1318,6 +1318,7 @@ impl LayoutThread {
                                                          &mut layout_context);
         }
 
+        self.first_reflow.set(false);
         self.respond_to_query_if_necessary(&data.reflow_goal,
                                            &mut *rw_data,
                                            &mut layout_context,
@@ -1618,8 +1619,6 @@ impl LayoutThread {
                                                     &mut *layout_context,
                                                     rw_data);
 
-        self.first_reflow.set(false);
-
         if opts::get().trace_layout {
             layout_debug::end_trace(self.generation.get());
         }

diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -14546,6 +14546,12 @@
      {}
     ]
    ],
+   "mozilla/first-reflow-sheet-assert.html": [
+    [
+     "/_mozilla/mozilla/first-reflow-sheet-assert.html",
+     {}
+    ]
+   ],
    "mozilla/focus_blur.html": [
     [
      "/_mozilla/mozilla/focus_blur.html",
@@ -27925,6 +27931,10 @@
    "f2ec5f89521fb4eda64a5e70249bbfb8850c4278",
    "testharness"
   ],
+  "mozilla/first-reflow-sheet-assert.html": [
+   "8a0cf9152c3f2421d3e418f824f02c915092d78f",
+   "testharness"
+  ],
   "mozilla/focus_blur.html": [
    "2735c5c482e38743b0976789af858075c54408c1",
    "testharness"

diff --git a/tests/wpt/mozilla/tests/mozilla/first-reflow-sheet-assert.html b/tests/wpt/mozilla/tests/mozilla/first-reflow-sheet-assert.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Issue 18631: Assertion failure when double-adding the UA sheets to the page</title>
+<style>
+* { display: none }
+</style>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+// Trigger two forced reflows.
+test(function() {
+  document.documentElement.offsetTop;
+  document.documentElement.offsetTop;
+  assert_true(true, "Didn't assert");
+}, "Passes if it doesn't assert");
+</script>