Fatal error with ACF

[Marycka9]

Warning: A non-numeric value encountered in
/wp-content/plugins/versionpress/src/Storages/Serialization/SerializedDataToIniConverter.php
on line 390

Warning: A non-numeric value encountered in
/wp-content/plugins/versionpress/src/Storages/Serialization/SerializedDataToIniConverter.php
on line 390

Warning: Cannot modify header information - headers already sent by (output started at
/wp-content/plugins/versionpress/src/Storages/Serialization/SerializedDataToIniConverter.php:390)
in /wp-includes/pluggable.php on line 1251

Warning: Cannot modify header information - headers already sent by (output started at /wp-content/plugins/versionpress/src/Storages/Serialization/SerializedDataToIniConverter.php:390) in /wp-includes/pluggable.php on line 1254

[pavelevap]

Hi @Marycka9,

do you have any example or steps to reproduce? It is probably related to some specific ACF data or settings.

Problem is related to following line of code (throws warning in PHP 7.1 when using math operation on non-numeric strings):

versionpress/plugins/versionpress/src/Storages/Serialization/SerializedDataToIniConverter.php

Line 390 in 9671af8

$subkey += 0; // convert to number

[Marycka9]

The example is very simple:
I save a new group of fields for the page and this error occurs. Although the data is saved.

[pavelevap]

Which version of ACF and WordPress do you use? Do you have Gutenberg editor active?

My clean installation is WP 5.1.1, ACF 5.7.12 and I tried to create one field group with text field and I did not encountered your error. I think that it is related to some specific field or settings?

I found some other Notices (on Plugins page after ACF activation), but nothing like you described.