Rewrite product attribute helper using new filter

[Ninos]

After following woocommerce PR (woocommerce/woocommerce#62572) it's "now" (in WC >= 10.6) easier to update product attributes.

So thx for your crazy workaround here, but following quote in your code is (happily) no longer valid :D

// This is the only nice way to update attributes after Woo has updated product attributes

TODO

The helper class includes following function get_attribute(), which is using WC_GZD_Product_Attribute, I'm not sure if it's possible to remove this part without breaking anything. In my opinion the whole WC_GZD_Product_Attribute class should be removed (also used somewhere in importer script).

PS: WC 10.6 is still not released & this would also break compatibility with instances updating germanized but not woocommerce. So we may should wait a while before merging... :'D

[dennisnissle]

Hi @Ninos,

thanks for your work on making this easier to achieve :) We will definitely need a backwards compatibility here for WooCommerce < 10.6 so we might need to add some checks whether the current version already has those changes implemented or not and leave the original implementation in tact for some time.

Best,
Dennis

[Ninos]

@dennisnissle yeah good point! Added some fallback to the static instance() function & also removed the unnessessary get_attribute() method (still in use by the deprecated helper class).

Tested this PR in combination with my patched woocommerce version, seems working fine. Haven't tested following:

• deprecated routine (still working fine with wc < 10.6.0?)
• product import/export