Setup Install `phpcs` and the moodlehq coding standards globally: composer global require moodlehq/moodle-cs Ensure that your global vendor binaries directory is in your $PATH as noted at https://getcomposer.org/doc/03-cli.md#global - this will depend on your installation, but usually it's a case of updating your .bashrc or .zshrc (or whatever shell you use) to add: export PATH=~/.composer/vendor/bin:$PATH Test Go to your moodle instance's root folder. Make sure you're using the correct nodejs version and that grunt-cli is installed. Assuming you have nvm : nvm install npm i Ensure you do not already have the phpcs.xml file: rm .phpcs.xml Remove any default standard for phpcs: phpcs --config-delete default_standard Run phpcs against course/format/classes : phpcs -sp course/format/classes Confirm that there were some warnings about print_error() (which is a Moodleism) Note: There are also some other warnings Run phpcs against an external file, for example lib/zipstream : phpcs -sp lib/zipstream Confirm that loads of Moodle-specific errors/warnings are shown (e.g. header) (At this point we don't know how to ignore it) Generate the ignorefile: npx grunt ignorefiles Run phpcs against an external file again, for example lib/zipstream : phpcs -sp lib/zipstream Confirm that there was no output at all Run phpcs with increased verbosity to check that files are appropriately ignored: phpcs -spvv lib/zipstream Confirm that the file was loaded: Processing ruleset /Users/nicols/Sites/moodles/sm/moodle/.phpcs.xml *Confirm that the Moodle ruleset was then used: Processing rule "moodle" Confirm that a number of global ignore patterns were added, including lib/zipstream : => added global absolute ignore pattern: lib/zipstream/ Remove the Moodle standard but ensure that phpcs is still instaled composer global remove moodlehq/moodle-cs composer global require squizlabs/php_codesniffer Run phpcs on a file again phpcs index.php Confirm that it complained that no sniffs were avaialble : ERROR: No sniffs were registered   Run "phpcs --help" for usage information Add the moodle-local_codechecker plugin: git clone https://github.com/moodlehq/moodle-local_codechecker local/codechecker Try to run the global phpcs again: phpcs index.php Confirm that it failed spectacularly : ➜ sm git:(MDL-74511-master) ✗ phpcs lib/zipstream PHP Fatal error: Cannot declare class PHP_CodeSniffer\Standards\PEAR\Sniffs\Commenting\FileCommentSniff, because the name is already in use in /Users/nicols/Sites/moodles/sm/moodle/local/codechecker/phpcs/src/Standards/PEAR/Sniffs/Commenting/FileCommentSniff.php on line 16 PHP Stack trace: PHP 1. {main}() /Users/nicols/.composer/vendor/squizlabs/php_codesniffer/bin/phpcs:0 ... Instead run the phpcsp from the local/codechecker directory: local/codechecker/phpcs/bin/phpcs index.php *Confirm that it ran the included Moodle sniffs: FILE: /Users/nicols/Sites/moodles/sm/moodle/index.php ------------------------------------------------------------------------------------------------------- FOUND 1 ERROR AFFECTING 1 LINE ------------------------------------------------------------------------------------------------------- 25 | ERROR | Expected MOODLE_INTERNAL check or config.php inclusion. Change in global state detected. -------------------------------------------------------------------------------------------------------   Time: 157ms; Memory: 12MB Run the local/codechecker version against lib/zipstream again: local/codechecker/phpcs/bin/phpcs -sp lib/zipstream Confirm that no files were processed Run phpcs with increased verbosity to check that files are appropriately ignored: local/codechecker/phpcs/bin/phpcs -spvv lib/zipstream Confirm that the file was loaded: Processing ruleset /Users/nicols/Sites/moodles/sm/moodle/.phpcs.xml *Confirm that the Moodle ruleset was then used: Processing rule "moodle" Confirm that a number of global ignore patterns were added, including lib/zipstream : => added global absolute ignore pattern: lib/zipstream/