MDL-67114 core: php74 fix. Fix use of scalar as array in core

There are various places where it's not guaranteed that the
variable being used is array, and instead, can be null, bool, int...

We need to check that because php74 warns about it.

Where possible we have used the coalesce operator as
replacement for isset() ternary operations.

competency/tests/privacy_test.php

@@ -2302,7 +2302,7 @@ public function test_export_data_for_user_about_their_learning_plans() {
         $this->assertEquals('-', $comp['rating']['rating']);
         $comp = $data->competencies[2];
         $this->assertEquals($comp4->get('shortname'), $comp['name']);
-        $this->assertNull($comp['rating']['rating']);
+        $this->assertNull($comp['rating']);
         $data = writer::with_context($u1ctx)->get_data(array_merge($path, ["{$p1a->get('name')} ({$p1a->get('id')})",
             get_string('commentsubcontext', 'core_comment')]));
         $this->assert_exported_comments(['Hello.', 'It\'s me.', 'After all these years...'], $data->comments);
@@ -2320,7 +2320,7 @@ public function test_export_data_for_user_about_their_learning_plans() {
         $this->assertEquals('C', $comp['rating']['rating']);
         $comp = $data->competencies[2];
         $this->assertEquals($comp4->get('shortname'), $comp['name']);
-        $this->assertNull($comp['rating']['rating']);
+        $this->assertNull($comp['rating']);
 
         // This plan is complete.
         $data = writer::with_context($u1ctx)->get_data(array_merge($path, ["{$p1c->get('name')} ({$p1c->get('id')})"]));

enrol/meta/lib.php

@@ -120,10 +120,12 @@ public function add_instance($course, array $fields = null) {
         require_once("$CFG->dirroot/enrol/meta/locallib.php");
 
         // Support creating multiple at once.
-        if (is_array($fields['customint1'])) {
+        if (isset($fields['customint1']) && is_array($fields['customint1'])) {
             $courses = array_unique($fields['customint1']);
-        } else {
+        } else if (isset($fields['customint1'])) {
             $courses = array($fields['customint1']);
+        } else {
+            $courses = array(null); // Strange? Yes, but that's how it's working or instance is not created ever.
         }
         foreach ($courses as $courseid) {
             if (!empty($fields['customint2']) && $fields['customint2'] == ENROL_META_CREATE_GROUP) {

lib/editor/tests/fixtures/editor_form.php

@@ -44,7 +44,7 @@ class editor_form extends moodleform {
      */
     protected function definition() {
         $mform = $this->_form;
-        $editoroptions = $this->_customdata['editoroptions'];
+        $editoroptions = $this->_customdata['editoroptions'] ?? null;
 
         // Add header.
         $mform->addElement('header', 'myheader', 'Editor in Moodle form');

lib/filestorage/file_system.php

@@ -416,11 +416,16 @@ public function is_image_from_storedfile(stored_file $file) {
     protected function get_imageinfo_from_path($path) {
         $imageinfo = getimagesize($path);
 
+        if (!is_array($imageinfo)) {
+            return false; // Nothing to process, the file was not recognised as image by GD.
+        }
+
         $image = array(
                 'width'     => $imageinfo[0],
                 'height'    => $imageinfo[1],
                 'mimetype'  => image_type_to_mime_type($imageinfo[2]),
             );
+
         if (empty($image['width']) or empty($image['height']) or empty($image['mimetype'])) {
             // GD can not parse it, sorry.
             return false;

lib/form/duration.php

@@ -200,7 +200,7 @@ function onQuickFormEvent($event, $arg, &$caller) {
                 break;
 
             case 'createElement':
-                if ($arg[2]['optional']) {
+                if (!empty($arg[2]['optional'])) {
                     $caller->disabledIf($arg[0], $arg[0] . '[enabled]');
                 }
                 $caller->setType($arg[0] . '[number]', PARAM_FLOAT);

lib/form/filetypes.php

@@ -221,6 +221,8 @@ public function onQuickFormEvent($event, $arg, &$caller) {
      */
     public function validateSubmitValue($value) {
 
+        $value = $value ?? ['filetypes' => null]; // A null $value can arrive here. Coalesce, creating the default array.
+
         if (!$this->allowall) {
             // Assert that there is an actual list provided.
             $normalized = $this->util->normalize_file_types($value['filetypes']);

lib/tests/session_manager_test.php

@@ -835,7 +835,7 @@ public function test_get_locked_page_at($url, $time) {
         $SESSION->recentsessionlocks = $this->sessionlock_history();
 
         $page = \core\session\manager::get_locked_page_at($time);
-        $this->assertEquals($url, $page['url']);
+        $this->assertEquals($url, is_array($page) ? $page['url'] : null);
     }
 
     /**

mod/glossary/import_form.php

@@ -10,7 +10,7 @@ class mod_glossary_import_form extends moodleform {
     function definition() {
         global $CFG;
         $mform =& $this->_form;
-        $cmid = $this->_customdata['id'];
+        $cmid = $this->_customdata['id'] ?? null;
 
         $mform->addElement('filepicker', 'file', get_string('filetoimport', 'glossary'));
         $mform->addHelpButton('file', 'filetoimport', 'glossary');

mod/wiki/comments_form.php

@@ -10,8 +10,8 @@ class mod_wiki_comments_form extends moodleform {
     protected function definition() {
         $mform = $this->_form;
 
-        $current = $this->_customdata['current'];
-        $commentoptions = $this->_customdata['commentoptions'];
+        $current = $this->_customdata['current'] ?? null;
+        $commentoptions = $this->_customdata['commentoptions'] ?? null;
 
         // visible elements
         $mform->addElement('editor', 'entrycomment_editor', get_string('comment', 'glossary'), null, $commentoptions);

mod/wiki/parser/parser.php

@@ -47,7 +47,7 @@ public static function get_section(&$string, $type, $section, $all_content = fal
             	return $content;
             }
             else {
-            	return $content[1];
+            	return is_array($content) ? $content[1] : null;
         	}
         }
         else {

question/engine/questionusage.php

@@ -701,7 +701,7 @@ public function prepare_simulated_post_data($simulatedresponses) {
             // Behaviour vars should not be processed by question type, just add prefix.
             $behaviourvars = $this->get_question_attempt($slot)->get_behaviour()->get_expected_data();
             foreach (array_keys($responsedata) as $responsedatakey) {
-                if ($responsedatakey[0] === '-') {
+                if (is_string($responsedatakey) && $responsedatakey[0] === '-') {
                     $behaviourvarname = substr($responsedatakey, 1);
                     if (isset($behaviourvars[$behaviourvarname])) {
                         // Expected behaviour var found.

repository/dropbox/classes/dropbox.php

@@ -181,7 +181,7 @@ protected function fetch_dropbox_content($endpoint, $data = []) {
      * @throws  moodle_exception
      */
     protected function check_and_handle_api_errors($data) {
-        if ($this->info['http_code'] == 200) {
+        if (!is_array($this->info) or $this->info['http_code'] == 200) {
             // Dropbox only returns errors on non-200 response codes.
             return;
         }