Improve wp-cache config functions

[stodorovic]

• Improve regular expressions in functions wp_cache_replace_line and wp_cache_update_rejected_pages
• Copy fixed CS (wp-cache-config-sample.php) from PHPCS fixes for wp-cache-config-sample.php #484 props @robjarsen
• Introduce function wpsc_var_export

[stodorovic]

Tests for function wpsc_var_export:

var_dump( wpsc_var_export( false ) );
var_dump( wpsc_var_export( true ) );
var_dump( wpsc_var_export( 0 ) );
var_dump( wpsc_var_export( '0' ) );
var_dump( wpsc_var_export( 'test' ) );
var_dump( wpsc_var_export( array( ) ) );
var_dump( wpsc_var_export( array( 'bot1', 'bot2' ) ) );
var_dump( wpsc_var_export( array( 0 => 'bot1', 1 => 'bot2' ) ) );
$obj = new stdclass();
$obj->test = 'test';
var_dump( wpsc_var_export( $obj ) );

Output:

test-scripts/wpsc/test1.php:19:
string(5) "false"
test-scripts/wpsc/test1.php:20:
string(4) "true"
test-scripts/wpsc/test1.php:21:
string(1) "0"
test-scripts/wpsc/test1.php:22:
string(3) "'0'"
test-scripts/wpsc/test1.php:23:
string(6) "'test'"
test-scripts/wpsc/test1.php:24:
string(7) "array()"
test-scripts/wpsc/test1.php:25:
string(23) "array( 'bot1', 'bot2' )"
test-scripts/wpsc/test1.php:26:
string(23) "array( 'bot1', 'bot2' )"
test-scripts/wpsc/test1.php:29:
string(52) "stdClass::__set_state(array(    'test' => 'test', ))"

I've also checked wp_cache_setting. It seems that all variants work as should.

I'll avoid replace spaces when $var is object because it could make some side effects. For arrays, we don't need keys and config file is more readable.

[donnchawp]

That looks great, but I'll leave this until the next release after this one as it's a critical part of the plugin.

[stodorovic]

I agree. We need to carefully test everything. I'm still testing it..

[donnchawp]

$valid_nonce needs to be a global variable in the functions that update settings because the REST API in rest/class.wp-super-cache-rest-update-settings.php sets it to true so it can use these update functions.

If we want to verify the nonce in each update function the REST API update code has to be modified to generate a valid POST nonce too. Probably best to keep that for a different PR?