From d28b4ec3264148a652639b8ca416ba853b1db3f9 Mon Sep 17 00:00:00 2001
From: Shamim Rezaie <shamim@moodle.com>
Date: Mon, 6 Apr 2020 17:03:51 +1000
Subject: [PATCH] MDL-68343 output: fix html table structure

A <th> that contains no text may result in cells with missing or
incorrect header information. WAVE advises that we should make a cell
a <td> rather than a <th> if the cell must remain empty (such as the
top-left cell in a data table).

Also note that the scope attribute is only valid for <th>
---
 lib/outputcomponents.php | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/outputcomponents.php b/lib/outputcomponents.php
index f6d432d2a0b..490e3b488e2 100644
--- a/lib/outputcomponents.php
+++ b/lib/outputcomponents.php
@@ -2207,8 +2207,9 @@ class html_writer {
                     $heading->header = true;
                 }
 
-                if ($heading->header && empty($heading->scope)) {
-                    $heading->scope = 'col';
+                $tagtype = 'td';
+                if ($heading->header && (string)$heading->text != '') {
+                    $tagtype = 'th';
                 }
 
                 $heading->attributes['class'] .= ' header c' . $key;
@@ -2224,16 +2225,15 @@ class html_writer {
                     $heading->attributes['class'] .= ' ' . $table->colclasses[$key];
                 }
                 $heading->attributes['class'] = trim($heading->attributes['class']);
-                $attributes = array_merge($heading->attributes, array(
-                        'style'     => $table->align[$key] . $table->size[$key] . $heading->style,
-                        'scope'     => $heading->scope,
-                        'colspan'   => $heading->colspan,
-                    ));
+                $attributes = array_merge($heading->attributes, [
+                    'style'     => $table->align[$key] . $table->size[$key] . $heading->style,
+                    'colspan'   => $heading->colspan,
+                ]);
 
-                $tagtype = 'td';
-                if ($heading->header === true) {
-                    $tagtype = 'th';
+                if ($tagtype == 'th') {
+                    $attributes['scope'] = !empty($heading->scope) ? $heading->scope : 'col';
                 }
+
                 $output .= html_writer::tag($tagtype, $heading->text, $attributes) . "\n";
             }
             $output .= html_writer::end_tag('tr') . "\n";