Error in vendor/magento/module-shipping/Model/Config/Source/Allmethods.php - public function toOptionArray

[Tantuss]

Preconditions

Magento 2.2.2 but also 2.2.1

Steps to reproduce

This code is used by an external extension, but this should just work.
See also: magmodules/magento2-channable#28
But this is actually not the extensions bug, it is a bug in Magento 2.2 code.
See below my explanation.
I have no idea where else this is used in Magento, but if it is, there should be also an error visible.

Expected result

Dropdown box with all carriers, active and inactive.

Actual result

1 exception(s):
Exception #0 (Exception): Notice: Array to string conversion in vendor/magento/module-shipping/Model/Config/Source/Allmethods.php on line 61

Exception #0 (Exception): Notice: Array to string conversion in vendor/magento/module-shipping/Model/Config/Source/Allmethods.php on line 61
#0 vendor/magento/module-shipping/Model/Config/Source/Allmethods.php(61): Magento\Framework\App\ErrorHandler->handler(8, 'Array to string...', '/Users/jw/Proje...', 61, Array)
#1 vendor/magento/module-config/Model/Config/Structure/Element/Field.php(458): Magento\Shipping\Model\Config\Source\Allmethods->toOptionArray(false)
#2 vendor/magento/module-config/Model/Config/Structure/Element/Field.php(376): Magento\Config\Model\Config\Structure\Element\Field->_getOptionsFromSourceModel(Object(Magento\Shipping\Model\Config\Source\Allmethods))

---

Looking into this Magento code on this line:
'label' => '[' . $carrierCode . '] ' . $methodTitle,

At the $carrierCode = 'usps', I get an array returned.
This results in the error above.

So a simple quick fix is to change:

$methods[$carrierCode]['value'][] = [
'value' => $carrierCode . '_' . $methodCode,
'label' => '[' . $carrierCode . '] ' . $methodTitle,
];

into:
if(!is_array($methodTitle))
$methods[$carrierCode]['value'][] = [
'value' => $carrierCode . '_' . $methodCode,
'label' => '[' . $carrierCode . '] ' . $methodTitle,
];

But this is not the complete correct solution, but it makes my page working.

UPD from @joni-jones

To reproduce this issue you need to manually insert carries/usps/allowed_methods NULL into core_config_data table and call \Magento\Shipping\Model\Config\Source\Allmethods::toOptionArray method.

The issue not in the \Magento\Shipping\Model\Config\Source\Allmethods::toOptionArray but how \Magento\Usps\Model\Carrier::getAllowedMethods (and other similar methods) processes invalid configuration.

[Tantuss]

To make it more complete..
If you look here:
vendor/magento/module-usps/Model/Carrier.php

Line 1148: public function getAllowedMethods()

You see that the return of this function is an array.

So the error is a logical result.

[YevSent]

Hi, @Tantuss, did you get the same error on the fresh installation of Magento without extensions? I've checked described case and I didn't get any errors.

According to a described example with USPS, the $carrierMethods contains array in the following format:

array (
  '0_FCLE' => 
  Magento\Framework\Phrase::__set_state(array(
     'text' => 'First-Class Mail Large Envelope',
  )),
...
  1 => 
  Magento\Framework\Phrase::__set_state(array(
     'text' => 'Priority Mail',
  )),
...
  'INT_20' => 
  Magento\Framework\Phrase::__set_state(array(
     'text' => 'Priority Mail International Small Flat Rate Envelope',
  )),
)

So, $methodTitle is a string, not an array.

[Tantuss]

Of course I do not try it on a fresh installation without any configurations.
I assume Magento is not developed to be only installed default and that configuration should be done.

Set in the core_config_data table the path:
carriers/usps/allowed_methods
to a value of 'NULL'.

(so basically nothing selected)

Then you get back the array at the wrong variable.

So probably the mistake is in the USPS extension. So here:
vendor/magento/module-usps/Model/Carrier.php
Line 1148: public function getAllowedMethods()

[YevSent]

Of course I do not try it on a fresh installation without any configurations.
I assume Magento is not developed to be only installed default.

It helps to understand if extensions could be a reason for this issue.

Set in the core_config_data table the path:
carriers/usps/allowed_methods
to a value of 'NULL'.
(so basically nothing selected)

This behavior doesn't seem correct because you don't have a possibility to don't select at least one allowed method, also, by default, the Use system value option is enabled for allowed shipping methods and the configuration will be read from XML because there are no any USPS configurations in core_config_data table.

So, the described case is artificial it might happen only if you manually set invalid data into the database. But agree, the code should validate such behavior.

[Tantuss]

It might be possible in Magento 1 and it might be there because of migration from Magento 1 to 2.

[Tantuss]

This behavior doesn't seem correct because you don't have a possibility to don't select at least one allowed method, also, by default, the Use system value option is enabled for allowed shipping methods and the configuration will be read from XML because there are no any USPS configurations in core_config_data table.

It might seem not correct, but it is definitely possible to do it from the user interface. Just set 1 as active, saved, checked db and it was there. Then unselected that 1 and there was again NULL in the database.

So it is not only related to migration, it is also just easy possible from the UI.