phpMyAdmin's ruleset is based on PEAR standards. One of this standard (PEAR_Sniffs_NamingConventions_ValidVariableNameSniff) is to name class' attributes / methods with a leading underscore when the element is protected / private.

This rule is quite useful because it helps to see very quickly if an element is public or not. But http://www.php-fig.org/psr/psr-2/#4-2-properties asks not to use this leading underscore.

For attributes, I'm not sure this is a big deal because almost all the attributes shouldn't be visible and accessible only by getters / setters. But for methods, there is nothing to know the visibility of a method. However actual IDE help to see this.

Do you think that we should follow PSR2? Only for attributes maybe?

Should we consider to base our ruleset on another standard closest to PSR rules?

Thanks for your feedback,

H.