Gravity Forms → Product price `29.95` `=` `29.949999999999999`

[remcotolsma]

https://secure.helpscout.net/conversation/1696891636/23013?folderId=1425713

I can reproduce this issue on a Local WordPress installation.

After some debugging i think this has something to do with serialize_precision configuration option.

I couldn't reproduce this setting via PHPUnit or via https://3v4l.org/, it seems that serialize_precision is set to -1 in these environments:

echo ini_get( 'serialize_precision' );

php -r "echo ini_get( 'serialize_precision' );"

If we set serialize_precision to 17 it's behaviour changes:

ini_set( 'serialize_precision', 17 );

$value = 29.95;

var_dump( json_encode( $value ) );

[remcotolsma]

Added a test to reproduce this issue: https://github.com/pronamic/wp-number/commit/13e49a5da0f0ba621206a0a57d8dca8bdcf4ff32

Should we always set serialize_precision to -1 or should we simplify this by using (string) $float?

[remcotolsma]

I think we should go for the serialize_precision to -1 approach. The (string) $float behaviour can also be influenced via the precision option.

<?php

ini_set( 'serialize_precision', 17 );
ini_set( 'precision', 17 );

$value = 29.95;

var_dump( json_encode( $value ) );

var_dump( (string) $value );

[remcotolsma]

• PHP overall
  • 0 mode (EG(precision)= -1) float outputs values rounded to nearest.
• Standard module and JSON
  • serialize(), var_export(), json_encode - Use PG(serialize_precision) and 0 mode by default.

https://wiki.php.net/rfc/precise_float_value

Since we use json_encode we only have to temporary set serialize_precision to -1.

[remcotolsma]

Improved in https://github.com/pronamic/wp-number/compare/44c28cd0cdfb305e62a33ff4d05141d7430ccfad...e4682600b69906e005fe6aaa6af71febeea88d9b and https://github.com/wp-pay-extensions/gravityforms/commit/8b2bea4a3c0f3cd4a4aa5c87936eca17806dff9e.