With config validation we can declare a config key to be nullable. When submitting a config form with an empty string in a textfield, or an empty select element, the config is saved as an empty string. It is possible to use a callback (as below) to convert empty strings to null, but it's a bit awkward.
$form['foo'] = [
'#title' => $this->t('Foo'),
'#type' => 'textfield',
'#config_target' => new ConfigTarget(
'my_module.config,
'foo',
toConfig: static fn (string $value) => $value ?: NULL,
),
];
Provide a way for ConfigTarget to treat empty values as null. Maybe it's another param in the constructor, or maybe a fluent setter, like new ConfigTarget('my_module.config', 'foo')->convertEmptyToNull()
Figure out the best DX
Do it
Active
11.0 🔥
Last updated
Not sure if it was in an issue or in Slack but somewhere @alexpott wondered whether NULL is really the correct thing to do for config string values and whether we should just use empty string instead to avoid having to handle conversion from UI input.