From 898dd7bf5bfc733f444bd10a58024fbf705945a8 Mon Sep 17 00:00:00 2001
From: Paul Holden <paulh@moodle.com>
Date: Wed, 21 Oct 2020 00:22:23 +0100
Subject: [PATCH] MDL-69201 core: consistent table primary sort column/order.

---
 lib/tablelib.php | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/tablelib.php b/lib/tablelib.php
index 63510a655196d..e464d39e8be46 100644
--- a/lib/tablelib.php
+++ b/lib/tablelib.php
@@ -1201,6 +1201,12 @@ protected function show_hide_link($column, $index) {
     function print_headers() {
         global $CFG, $OUTPUT;
 
+        // Set the primary sort column/order where possible, so that sort links/icons are correct.
+        [
+            'sortby' => $primarysortcolumn,
+            'sortorder' => $primarysortorder,
+        ] = $this->get_primary_sort_order();
+
         echo html_writer::start_tag('thead');
         echo html_writer::start_tag('tr');
         foreach ($this->columns as $column => $index) {
@@ -1209,14 +1215,6 @@ function print_headers() {
             if ($this->is_collapsible) {
                 $icon_hide = $this->show_hide_link($column, $index);
             }
-
-            $primarysortcolumn = '';
-            $primarysortorder  = '';
-            if (reset($this->prefs['sortby'])) {
-                $primarysortcolumn = key($this->prefs['sortby']);
-                $primarysortorder  = current($this->prefs['sortby']);
-            }
-
             switch ($column) {
 
                 case 'fullname':
@@ -1596,6 +1594,22 @@ protected function sort_link($text, $column, $isprimary, $order) {
                 ]) . ' ' . $this->sort_icon($isprimary, $order);
     }
 
+    /**
+     * Return primary sorting column/order, either the first preferred "sortby" value or defaults defined for the table
+     *
+     * @return array
+     */
+    protected function get_primary_sort_order(): array {
+        if (reset($this->prefs['sortby'])) {
+            return $this->get_sort_order();
+        }
+
+        return [
+            'sortby' => $this->sort_default_column,
+            'sortorder' => $this->sort_default_order,
+        ];
+    }
+
     /**
      * Return sorting attributes values.
      *