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PHP CodeSniffer

PHPCodeSniffer is a tool used to analyse PHP code using a set of rules. In many cases these rules can be used to automatically fix the errors they identify.

Moodle has two sets of published rule-sets intended to meet the Moodle Coding Style, and identify any parts of the code do not conform to this style. These are:

  • moodle - The standard ruleset which meets all variants of the coding style
  • moodle-extra - The extended standard which includes recommended best practices

We recommend use of the moodle-extra standard, particularly when writing new code.


The recommended method of installation is via the global composer command:

composer global config minimum-stability dev
composer global require moodlehq/moodle-cs

This ensures that you have a single copy of the standard used for all code.

Updates to the CodeSniffer are not applied automatically. To determine if updates are required, run the following via the command line:

composer global show -l

To apply updates:

composer global update


Since 4.1.0
Since 4.0.1
Since 3.11.7

A PHPCS configuration is included in the Moodle codebase and ensures that the correct phpcs ruleset is always used for the Moodle codebase.

This can be further extended by generating an additional configuration to ignore all third-party libraries using the grunt ignorefiles command. See grunt for further information on using Grunt.

If you would like to make use of the moodle-extra standard then you should create a .phpcs.xml file with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="MoodleCore">
<rule ref="./phpcs.xml"/>
<rule ref="moodle-extra"/>

This will extend the standard configuration, and apply the extra standard on top of it.

Moodle 3.10 and earlier

The easiest way to have PHP CodeSniffer pick up your preferred style is via a local configuration file.

You can create a file named .phpcs.xml with the following contents:

<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="MoodleCore">
<rule ref="moodle"/>

If you wish to use the moodle-extra coding style, then you can use the following content:

<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="MoodleCore">
<rule ref="moodle-extra"/>

Third-party library code will not be ignored with these versions of Moodle.

Ignoring the file with Git

We recommend configuring your code checkout to ignore the .phpcs.xml file by adding a local ignore record to .git/info/exclude

Community plugins, and older Moodle versions

If you are developing your own plugin outside of the main Moodle directory, or you are working with an older version of Moodle, the easiest way to configure phpcs to use the Moodle ruleset is by creating a local phpcs.xml.dist configuration at the root directory of your repository with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="MoodleCore">
<rule ref="moodle"/>

If you do not wish to include this file in your repository, or you are using an older version of Moodle, then you should add this to your local gitignore files. On a Unix-like system this can be achieved with:

echo phpcs.xml.dist >> .git/info/exclude

The .git/info/exclude file is a per-repository version of the .gitignore file. Whilst .gitignore is tracked within the Moodle codebase and a version is shipped with Moodle, the .git/info/exclude file is local to your git clone.

See the gitignore documentation for more information on the gitignore feature.

System-side default standard

Although not recommended, you can configure the Moodle ruleset as the system-wide default for phpcs:

phpcs --config-set default_standard moodle
Not recommended

This approach is not recommended and is only preserved for reference.

Editor integrations

Many modern editors and IDEs will natively integrate with PHPCodeSniffer, and since Moodle versions 3.11.7, 4.0.1, and 4.1.0, no additional configuration is required.

For older versions many editors will allow you to manually configure the PHPCodeSniffer standard to use, for example, the VS Code PHPCodeSniffer extension can be configured in this way.

If you get the error: 'ERROR: Referenced sniff "moodle" does not exist', you may need to specify the location of the CodeSniffer in your IDE. Note the location when installing, and add that to the settings. e.g. "Exec: Linux": "/home/xxxx/.config/composer/vendor/bin/phpcs"; and select "Automatic" as the Standard.

Advanced Usage

Ignoring warnings

You can run the CodeSniffer with the -n flag to ignore warnings:

phpcs -n index.php
28 | ERROR | line indented incorrectly; expected 0 spaces, found 4
50 | ERROR | line indented incorrectly; expected 0 spaces, found 4

Recursive analysis

If you give the name of a folder instead of a file, it will search, analyse and report on all PHP files found in this folder and all its subfolders. This will produce a full report for each PHP file. Since this is likely to be too much information, you may want to print only a summary report, by using the following syntax (search the files/ folder as an example):

phpcs --report=summary blocks/html
/var/www/html/moodle/blocks/html/block_html.php 24 0
/var/www/html/moodle/blocks/html/edit_form.php 16 0
/var/www/html/moodle/blocks/html/lib.php 11 0
/var/www/html/moodle/blocks/html/settings.php 6 0
/var/www/html/moodle/blocks/html/backup/moodle2/backup_html_block_task.class.php 2 0
/var/www/html/moodle/blocks/html/backup/moodle2/restore_html_block_task.class.php 3 0
/var/www/html/moodle/blocks/html/classes/privacy/provider.php 13 0
/var/www/html/moodle/blocks/html/classes/search/content.php 6 0
/var/www/html/moodle/blocks/html/tests/search_content_test.php 6 0

Time: 626ms; Memory: 16MB

Other report formats

CodeSniffer can export its reports in the following formats:

  1. full: default, shown first above
  2. summary: also shown above
  3. xml: Simple XML format
  4. csv: Comma-separated list
  5. checkstyle: XML format intended for use with CruiseControl

See also

  1. Coding
  2. Coding style