From 3cb02787cfc7d225acbe4982cf914c8f93116514 Mon Sep 17 00:00:00 2001
From: Jun Pataleta <jun@moodle.com>
Date: Thu, 12 Nov 2015 13:28:55 -0600
Subject: [PATCH 1/2] MDL-50935 atto_equation: Fix display of matrix template

Thanks to Geoffrey Rowland's fix suggestion.
---
 lib/editor/atto/plugins/equation/settings.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/editor/atto/plugins/equation/settings.php b/lib/editor/atto/plugins/equation/settings.php
index c7e5b13fe20..118611edb6c 100644
--- a/lib/editor/atto/plugins/equation/settings.php
+++ b/lib/editor/atto/plugins/equation/settings.php
@@ -159,7 +159,7 @@ if ($ADMIN->fulltree) {
 (a)
 [a]
 \lbrace{a}\rbrace
-\left| \begin{matrix} a_1 & a_2 \\ a_3 & a_4 \end{matrix} \right|
+\left| \begin{matrix} a_1 & a_2 \\\\ a_3 & a_4 \end{matrix} \right|
 \frac{a}{b+c}
 \vec{a}
 \binom {a} {b}

From 3f9a93b5228a7f10ad4abc34501cd8243182e98f Mon Sep 17 00:00:00 2001
From: Jun Pataleta <jun@moodle.com>
Date: Mon, 7 Nov 2022 14:40:30 +0800
Subject: [PATCH 2/2] MDL-50935 atto_equation: Add upgrade step to fix existing
 sites

---
 lib/editor/atto/plugins/equation/db/upgrade.php | 10 ++++++++++
 lib/editor/atto/plugins/equation/version.php    |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/editor/atto/plugins/equation/db/upgrade.php b/lib/editor/atto/plugins/equation/db/upgrade.php
index 7434c24196f..c3ffde655ee 100644
--- a/lib/editor/atto/plugins/equation/db/upgrade.php
+++ b/lib/editor/atto/plugins/equation/db/upgrade.php
@@ -38,5 +38,15 @@ function xmldb_atto_equation_upgrade($oldversion) {
     // Automatically generated Moodle v4.0.0 release upgrade line.
     // Put any upgrade step following this.
 
+    if ($oldversion < 2022110700) {
+        $oldmatrix = '\left| \begin{matrix} a_1 & a_2 \\ a_3 & a_4 \end{matrix} \right|';
+        $fixedmatrix = '\left| \begin{matrix} a_1 & a_2 \\\\ a_3 & a_4 \end{matrix} \right|';
+        $config = get_config('atto_equation', 'librarygroup4');
+        $newdefault = str_replace($oldmatrix, $fixedmatrix, $config);
+        set_config('librarygroup4', $newdefault, 'atto_equation');
+        // Atto equation savepoint reached.
+        upgrade_plugin_savepoint(true, 2022110700, 'atto', 'equation');
+    }
+
     return true;
 }
diff --git a/lib/editor/atto/plugins/equation/version.php b/lib/editor/atto/plugins/equation/version.php
index a5cab505501..47e9360b6cf 100644
--- a/lib/editor/atto/plugins/equation/version.php
+++ b/lib/editor/atto/plugins/equation/version.php
@@ -24,6 +24,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2022041900;        // The current plugin version (Date: YYYYMMDDXX).
+$plugin->version   = 2022110700;        // The current plugin version (Date: YYYYMMDDXX).
 $plugin->requires  = 2022041200;        // Requires this Moodle version.
 $plugin->component = 'atto_equation';  // Full name of the plugin (used for diagnostics).