Do not remove extra columns at the end of the table (#33451)

<col> and <colgroup> elements can be used to create extra columns that
have no cell. We were removing these columns and column groups, but in
general we shouldn't do that.

Now we will only remove them if the table has no row nor row group.
matching WebKit and the expectations of some tests. But note that Gecko
and Blink never remove them.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

1 files changed, 11 insertions, 21 deletions

diff --git a/components/layout_2020/table/construct.rs b/components/layout_2020/table/construct.rs
index 61f939e9300..461267bdad0 100644
--- a/components/layout_2020/table/construct.rs
+++ b/components/layout_2020/table/construct.rs
@@ -271,8 +271,8 @@ impl TableBuilder {
     }
 
     pub fn finish(mut self) -> Table {
+        self.adjust_table_geometry_for_columns_and_colgroups();
         self.do_missing_cells_fixup();
-        self.remove_extra_columns_and_column_groups();
         self.reorder_first_thead_and_tfoot();
         self.do_final_rowspan_calculation();
         self.table
@@ -287,26 +287,16 @@ impl TableBuilder {
     }
 
     /// It's possible to define more table columns via `<colgroup>` and `<col>` elements
-    /// than actually exist in the table. In that case, remove these bogus columns
-    /// to prevent using them later in layout.
-    fn remove_extra_columns_and_column_groups(&mut self) {
-        let number_of_actual_table_columns = self.table.size.width;
-        self.table.columns.truncate(number_of_actual_table_columns);
-
-        let mut remove_from = None;
-        for (group_index, column_group) in self.table.column_groups.iter_mut().enumerate() {
-            if column_group.track_range.start >= number_of_actual_table_columns {
-                remove_from = Some(group_index);
-                break;
-            }
-            column_group.track_range.end = column_group
-                .track_range
-                .end
-                .min(number_of_actual_table_columns);
-        }
-
-        if let Some(remove_from) = remove_from {
-            self.table.column_groups.truncate(remove_from);
+    /// than actually exist in the table. In that case, increase the size of the table.
+    ///
+    /// However, if the table has no row nor row group, remove the extra columns instead.
+    /// This matches WebKit, and some tests require it, but Gecko and Blink don't do it.
+    fn adjust_table_geometry_for_columns_and_colgroups(&mut self) {
+        if self.table.rows.is_empty() && self.table.row_groups.is_empty() {
+            self.table.columns.truncate(0);
+            self.table.column_groups.truncate(0);
+        } else {
+            self.table.size.width = self.table.size.width.max(self.table.columns.len());
         }
     }