Incorrect method return value in \Magento\Shipping\Model\Carrier\AbstractCarrier::getTotalNumOfBoxes()

[korostii]

Please see the method getTotalNumOfBoxes() in \Magento\Shipping\Model\Carrier\AbstractCarrier: https://github.com/magento/magento2/blob/2.2.2/app/code/Magento/Shipping/Model/Carrier/AbstractCarrier.php#L512-L531

Incoming $weight parameter is not checked to be integer. Moreover, even if it is, you can still get a float result when $weight > $maxPackageWeight since these are both arbitrary numbers.

This method is a member of AbstractCarrier class commonly used for 3-rd party implementations of the Shipmen Carrier SPI and might be used by 3rd-party developers in their modules.
In order to apply proper validation and\or rounding around the method's return results, it would be helpful to see the actual return value in PHPDocs which are commonly used by IDEs when providing hints, for example here: http://take.ms/9dnaD

Additionally, the method name is severely misleading: it implies the method is a getter, however it can modify object's internal state. Moreover, the value returned is in fact what seems to be an average weight of a box, not "Total number of boxes" as one might assume.

Backward Compatibility: Please note that Magento's USPS implementation expects float return value, implying internal knowledge of the method: https://github.com/magento/magento2/blob/2.2.2/app/code/Magento/Usps/Model/Carrier.php#L341
If any rounding is to be added, it should probably be done via a new extra method, deprecating the old one (if at all)

Preconditions

1. Magento CE 2.1.10, Magento CE 2.2.2
2. PHP 7.0.18

Steps to reproduce

1. Open file app/code/Magento/Shipping/Model/Carrier/AbstractCarrier.php
2. Scroll down to getTotalNumOfBoxes method

Expected result

1. Observe correct return type "float" declared in PHPDoc block
   OR proper rounding applied to the $weight variable.

Actual result

1. Observe incorrect return type "int" declared in PHPDoc block
   AND no rounding applied to $weight variable

[magento-engcom-team]

@korostii, thank you for your report.
We've acknowledged the issue and added to our backlog.

[magento-engcom-team]

Hi @cedmudit. Thank you for working on this issue.
Looks like this issue is already verified and confirmed. But if your want to validate it one more time, please, go though the following instruction:

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[magento-engcom-team]

Hi @korostii. Thank you for your report.
The issue has been fixed in #20898 by @cedmudit in 2.3-develop branch
Related commit(s):

• 56504e1d8b0bde92a0eba4cec2ef233ad147dfc9

The fix will be available with the upcoming 2.3.2 release.