[4.x]: Error with Conditions on Dropdown fields with Optgroup

[tommysvr]

What happened?

Description

When editing an Entry Type with an existing condition on a Dropdown field with an Optgroup, I'm getting an Undefined array key "value" error.

[web.ERROR] [yii\base\ErrorException:2] yii\base\ErrorException: Undefined array key "value" in /var/www/html/vendor/craftcms/cms/src/fields/conditions/OptionsFieldConditionRule.php:28

Trying to create a new condition based on a Dropdown field with an Optgroup doesn't error, but you're not able to add any rules.

It looks to be related to this change: 6ceb924

Steps to reproduce

1. Create a Dropdown field with an Optgroup
2. Add that to an Entry Type
3. Add a Condition to another field based on the Dropdown
4. Unable to add rules

Expected behavior

Able to add rules like this:

Actual behavior

Unable add any rules:

Craft CMS version

Tested on 4.6.1 and 4.7.0

PHP version

No response

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

No response

[i-just]

Thanks for all the info, Tommy! I raised a PR for this.

[brandonkelly]

Fixed in 4.7.1!