That can be coded into your plugin, to check for PHP version, WP version, etc etc.
I just thought it would be more convenient if the plugin browser notified users of any compatibility issues prior to installing the plugin. This would take some of the burden off of plugin developers.
Since there are so many different implementations of PHP, however, it would be a pretty tall order to put that into Core.
I’m not sure I get your meaning. Once the data is incorporated into the plugin api it would be fairly simple to add a few more checks in addition to the existing WordPress compatibility checks.
For example, this is the code where the wordpress version is checked (plugin-install.php line 341):
if ( !empty($api->tested) && version_compare( substr($GLOBALS['wp_version'], 0, strlen($api->tested)), $api->tested, '>') )<br />
echo '<div class="updated"><p>' . __('<strong>Warning:</strong> This plugin has <strong>not been tested</strong> with your current version of WordPress.') . '</p></div>';</p>
<p> else if ( !empty($api->requires) && version_compare( substr($GLOBALS['wp_version'], 0, strlen($api->requires)), $api->requires, '<') )<br />
echo '<div class="updated"><p>' . __('<strong>Warning:</strong> This plugin has <strong>not been marked as compatible</strong> with your version of WordPress.') . '</p></div>';
Assuming the api is updated to include a minimum php version data point you would just need to add the following to check if you meet the requirement:
<br />
if ( !empty($api->min_php) && version_compare( phpversion(), $api->min_php, '<') )<br />
echo '<div class="updated"><p>' . __('<strong>Warning:</strong> This plugin has <strong>not been marked as compatible</strong> with your version of PHP.') . '</p></div>';<br />
Unless there is something I’m not understanding it seems like the biggest challenge would be to update the plugin api to include the additional data from the readme, not wordpress itself.