Set Drupal to show all errors when developing your module. As an example of how this can help, if you are converting from D6 to D7, in hook forms you must replace the D6
$type = node_get_types('type', $node); with D7
$type = node_type_get_types($node);. The error is only reported when all PHP error reporting is switched on. Without the error reporting on, you get the dreaded White Screen of Death.
Change settings in your dev site
You can show all errors by adding a few lines to your local testing site's settings.php:
Note: Do not include the opening and closing PHP tags when you copy the code above. Those are already there in settings.php
In addition, navigate to Administration→ Configuration→ Development → logging and errors and select "All messages". (This sets
$conf['error_level'] = 2; .)
Switch on strict PHP error reporting
Or you can go through your development site's php.ini file, in the php folder, and switch all error reporting on. To do this, check through your php.ini file and set error reporting to
E_ALL | E_STRICT. The documentation there is very thorough, and you may find a different setting that's better suited to your needs. Warning: as the PHP documentation states, this setting is only for development sites, not for production sites.