Making changes show up during development

Sometime, when you are trying to do Moodle development, you edit the code, and nothing seems to change as a result. This is because, to improve performance, Moodle now has all sorts of caching built in. When this is happening, this page will try to give you the quickest way to make your changes show up in all situation.

General advice

1. In your development site, change most of the admin settings like 'Cache language strings', 'Cache JavaScript' to be suitable for development. Note that doing this will slow down your development site a bit.
2. If in doubt, visit http://your.domain/moodle/admin to check that the Moodle install is up-to-date.
3. And then http://your.domain/moodle/admin/purgecaches.php and click the 'Purge all caches' button. This will slow things down for the next few requests, until the caches have re-populated. Note there is also a CLI tool to purge caches.
4. Depending on what you changed in your plugin, then in addition to the above, you may need to remember to increase the version number in the plugin's version.php, or the changes will not show up.
5. You may have forgotten to run grunt.
6. If you have just added a new Behat or PHPunit test, you may need to re-run admin/tool/.../cli/init.php

The above steps are a brute force approach. They will probably work, but are probably not the fastest way.

Here's a quick overview about what changes need which actions to be followed with. Below, we list for all the various type of change you can make, the most efficient way to make the change show up.

Keep in mind that once you're done developing your plugin, you should always bump the version number.

Changed	Delete specific cache	Purge all caches	Bump plugin version	Other
PHP	opcache, if enabled	-	-
Autoloaded classes	x	-	-
JavaScript	x	-	-
CSS, SCSS, LESS	x	-	-
Language strings	x	-	-
Capabilities	-	-	x
Events	?	?	?
Scheduled tasks	-	-	x
Web services	?	?	?
Database structure	-	-	x
Behat	-	-	-	see below

PHP

After changing the PHP files (*.php), you should just need to press reload (F5) in your browser.

If you somehow have opcache enabled on your server, you may have to delete it depending on your settings.

Adding or removing an autoloaded class

If you get class-not-found errors, you need to either do any of these:

• GUI: visit http://your.domain/moodle/admin
• File system: Delete the file core_component.php in the moodledata cache directory.

JavaScript

AMD Modules

While changing older AMD Javascript Module source files (amd/src/*.js), if you have Administration -> Appearance -> AJAX and Javascript -> Cache Javascript turned off, then you should just need to reload (F5) in your browser. If JS caching is on, you need to re-run grunt, because Moodle will always prefer to load the minified modules then.

ES Modules

If you're using the newer ES module syntax, you always have to re-run grunt or have it running in watch mode, as the normal js files need to be transpiled by grunt (using babel) to be usable.

CSS, SCSS, LESS

After changing the CSS styles (*.css, *.scss, *.less) you may either:

• GUI: Purge all caches via /admin/purgecaches.php
• "developer way": Write a mini script that calls theme_reset_all_caches()

Language strings

After changing language pack strings (lang/en/type_plugin.php), you may either:

• Prevention: The best option is to turn off Admin -> Language -> Language settings -> Cache all language strings when doing development. Then you only need to press F5 to refresh to see your changes.
• GUI: Otherwise you need to Purge all caches (or just the Language strings cache) before reloading.
• "developer_way": Write a mini script that calls get_string_manager()->reset_caches()

Capabilities

After changing capabilities (db/access.php) you need to

1. Bump the plugin version number.
2. Go to admin -> Notifications.

Then check that the capabilities show up on Site administration > Users > Permissions > Define roles for any role.

Events

After changing event listeners (db/events.php) you don't seem to need to do anything. Event listeners don't seem to be cached in any way.

Scheduled tasks

After changing scheduled tasks (db/tasks.php) you need to

1. Bump the plugin version number.
2. Go to admin -> Notifications.

Then check that the task shows up on Admin -> Server -> Scheduled tasks.

Web services

After changing web services (db/services.php) ...

Database structure

After changing the database scheme (db/install.xml, db/upgrade.php) ...

Behat

After you add a new *.feature file, you need to re-run

$ php admin/tool/behat/cli/init.php

Mobile support for plugins

If you are doing the kind of development described in Mobile support for plugins, using a pre-built version of the app like https://mobileapp.moodledemo.net/.

Note, these steps were originally written by people mostly on question type plugins. Hopefully they are generally applicable, but if they don't make sense in your case, that might be why. Please edit to improve them.

General note

If there are lots of red error messages appearing in the JavaScript console (but not the very common error 'ERROR Error: Uncaught (in promise): null...' that repeats every minute and fills the console logs!) it is often necessary to clear site data and restart.

1. In browser developer tools, go to Application -> Clear storage.
2. Close the browser, and re-launch.

Adding mobile support to a plugin for the first time

1. Bump the plugin version number.
2. Go to admin -> Notifications.
3. F5 in the app to restart.

HTML template

After changing an existing template (mobile/*.html), just pull down in the app to refresh.

Client-side JavaScript

After changing an existing client-side JavaScript (mobile/*.js), press F5 in the browser developer tools to restart the app.

Server-side classes/output/mobile.php

???

Mobile CSS

1. Bump version number in db/mobile.php
2. Purge caches (specifically the tool_mobile/plugininfo MUC cache)
3. Press F5 to restart the app.