Shipping is not same as billing fails, if discount is applied

It's a tricky one!

The Commerce store is at http://www.thehealthybackbag.co.uk - it should be possible to reproduce the problem by adding one item to the basket and then going to the checkout page. But I haven't managed to reproduce it here, and others say everything is working for them too.

As I hear from other people who've seen the problem I'll post more info here.

Useful new symptom information: the problem occurs if a coupon code is added using commerce_discount/commerce_coupon.

I can now reproduce the problem. Changing "My Shipping information is the same as my Billing information" now results in a 500 server error from the AJAX call.

So not random, it's a problem caused by commerce_discount/commerce_coupon!

The error message is:

EntityMetadataWrapperException: Unable to get the data property
commerce_unit_price as the parent data structure is not set. in
EntityStructureWrapper->getPropertyValue() (line 438 of
/var/www/shared/drupal7/sites/all/modules/entity/includes/entity.wrapper.inc).

Since a "Free Shipping" discount works fine, I suspect it's something to do with the additional line item that the discount/coupon module adds to the order.

I'll try to diagnose the cause further when I get a spare moment.

Three hours more research (this is hard to debug, there are so many function and method calls going on!):

Additional symptoms:

* Error occurs if a Discount Coupon has been applied to the order.
* If you re-apply the Discount Coupon a second time (resulting in "The coupon you have entered has already been applied to your order") then everything works fine.

The error is triggered by the AJAX call which in turn calls commerce_customer_profile_copy_validate() to validate the commerce_customer_profile_copy field in the checkout form. This validation function saves the order, and at some point during the commerce_order_save() an exception is caused and it all stops with a 500 error.

OK, more info.

The problem seems to be that while validating the "The coupon you have entered has already been applied to your order" field the order is saved and refreshed and generally manipulated a great deal. Not sure why this is needed: there's an awful lot of code being run!

For some reason during this process the existing discount line item is being deleted and replaced with a duplicate one with a new ID, but the order in some places still refers to the original line item that is deleted so has no data.

The problem seems to stem from commerce_discount_commerce_cart_order_refresh() deleting and re-creating order discount line items. In the context of this particular AJAX call this results in the order becoming corrupted because it refers to the original discount line item which has been deleted.

Nope, still fails here.

Using:

• commerce_coupon 7.x-2.0-beta4+4-dev
• commerce_discount 7.x-1.0-alpha4+4-dev

If I apply a discount code to the order, using "My Shipping information is the same as my Billing information" causes a 500 error on the AJAX call, meaning customers cannot enter a separate shipping address.

The problem occurs if you:

1. Go to checkout.
2. Apply a discount code.
3. Choose to have a separate shipping address.

The problem does not occur if you:

1. Go to checkout.
2. Apply a discount code.
3. Apply the same discount code again (ignoring warning).
4. Choose to have a separate shipping address.

Moving to commerce_discount, as this problem still occurs with a very simple discount and with commerce_coupon disabled.

Demonstration with simple site:

1. Go to http://www.fonant.com/node/53
2. Add one to cart.
3. Go to checkout, where a fixed 10% order discount is applied.
4. Try to enter a different shipping address: AJAX fails with a 500 error.

Running with:

• commerce 7.x-1.10
• commerce_shipping 7.x-2.1
• commerce_discount 7.x-1.0-alpha4+4-dev

With:

• commerce 7.x-1.11
• commerce_discount 7.x-1.0-alpha5

I got:

EntityMetadataWrapperException: Unable to get the data property commerce_unit_price as the parent data structure is not set. in EntityStructureWrapper->getPropertyValue() (line 438 of /var/www/shared/drupal7/sites/all/modules/entity/includes/entity.wrapper.inc).

but with commerce_discount 7.x-1.x-dev (7.x-1.0-alpha6+2-dev) the error has gone!

Thank you for fixing this :)

Hmmm.. not quite. On my simple demo site the bug has gone away, but on a more complex site the bug still persists a little.

There still seems to be an initialisation problem, just the first time you want a different shipping address:

1. Add products to basket.
2. Add discount code at checkout.
3. Untick "My Shipping information is the same as my Billing information." => 500 ERROR!
4. Tick "My Shipping information is the same as my Billing information." => OK :)
5. Untick "My Shipping information is the same as my Billing information." => OK :)

From then on the shipping address toggle works fine, but if you refresh the checkout page (or go to the next page and then back again) the problem returns.

OK, I've updated my demo site to use coupon code for the discount, and the error is reproducible.

1. Go to http://www.fonant.com/node/53
2. Add one to cart.
3. Go to checkout, where shipping toggle works fine.
4. Enter "DISCOUNT" coupon code: a 10% order discount is applied.
5. Try to enter a different shipping address: AJAX fails with a 500 error.
6. Toggle the shipping address twice more, and it all works again.

• commerce 7.x-1.11
• commerce_discount 7.x-1.0-alpha5
• commerce_coupon 7.x-2.0-rc2

The error is slightly different now:

EntityMetadataWrapperException: Unable to get the data property type as the parent data structure is not set. in EntityStructureWrapper->getPropertyValue() (line 438 of /var/www/shared/drupal7/sites/all/modules/entity/includes/entity.wrapper.inc).

More testing shows that the bug remains even with commerce_coupon 7.x-2.0-rc2+2-dev

Sorry, I was, gave the wrong version numbers above. My demo site has:

• commerce 7.x-1.11
• commerce_discount 7.x-1.0-alpha6+2-dev
• commerce_coupon 7.x-2.0-rc2+2-dev

It's a lot better than it was: with a coupon code entered you still get a 500 error when trying to enter a different shipping address, but if you try again it works.

Here's the backtrace - there's a lot!

Thanks for the ideas :)

Oddly although commerce_donate was once installed, it is no longer enabled and has been uninstalled. I'll check for remnants.

The patch linked to for entity_metadata_wrapper sadly doesn't help.

Here's a print_r($this, TRUE) from where the exception is raised.