The transactionShippingMethod key unconditionally attempts to output the shipping "Carrier Code".
This is fine in most cases, but for "virtual" orders (ie, orders for which all products are virtual, and so there is no shipping information whatsoever), no CarrierCode is defined. This results in an illegal offset error (internal to Magento) when the non-existent carrier information is requested.
The pull request #29 attempts to correct this issue, using similar logic to that found within the checkout controllers. ie: only referencing shipping information if the order is not Virtual.
The transactionShippingMethod key unconditionally attempts to output the shipping "Carrier Code".
This is fine in most cases, but for "virtual" orders (ie, orders for which all products are virtual, and so there is no shipping information whatsoever), no CarrierCode is defined. This results in an illegal offset error (internal to Magento) when the non-existent carrier information is requested.
The pull request #29 attempts to correct this issue, using similar logic to that found within the checkout controllers. ie: only referencing shipping information if the order is not Virtual.