Editing checkout agreements throws exception

[cizgidekiadam]

Preconditions

1. Magento 2.1.2
2. Updated from 2.1 via composer
3. Single Store Mode enabled

Steps to reproduce

1. Create new checkout agreement.
2. Try to edit

Expected result

1. Open agreement for edit

Actual result

1. Warning: htmlspecialchars() expects parameter 1 to be string, array given in
   /vendor/magento/framework/Data/Form/Element/AbstractElement.php on line 286

[palamar]

Internal ticket MAGETWO-60143 has been created to track this issue.

[mosesmalone]

Same problem here on Magento 2.1.2.
Any workaround to delete a term that's been created?
I'd like to remove it, but can't, because editing is not possible :)

[mosesmalone]

sorry, found the entry in the database.
Table "checkout_agreement".

[mosesmalone]

I was able to fix it by changing Line 302 in /vendor/magento/framework/Data/Form/Element/AbstractElement.php from
return $this->_escape($value);
to
if(is_string($value)) { return $this->_escape($value); }

don't know if this causes any other issues though :)

[therool]

I encountered the same issue on magento 2.1.0 and found that the issue lies withing https://github.com/magento/magento2/blob/develop/app/code/Magento/CheckoutAgreements/Block/Adminhtml/Agreement/Edit/Form.php#L139. Megento expects that the value of hidden field is string but existing aggreement stores property is always array containing all the store ids it it associated with and is overwrites the default store id on https://github.com/magento/magento2/blob/develop/app/code/Magento/CheckoutAgreements/Block/Adminhtml/Agreement/Edit/Form.php#L186.

The fix is pretty easy - just change the line https://github.com/magento/magento2/blob/develop/app/code/Magento/CheckoutAgreements/Block/Adminhtml/Agreement/Edit/Form.php#L144 to
$model->setStores($this->_storeManager->getStore(true)->getId());

[KrystynaKabannyk]

@rbostan, the fix will be provided under MAGETWO-63840 (MAGETWO-60143 is closed as duplicate).