uc_product_feature_save() creates duplicate features / db_affected_rows() always returns 0

This is happening for me, and I'm Ubuntu 10.04 LTS. aka PHP 5.3, MySQL 5.x. I do not believe this is a PHP 5.3 issue though.

Here's how you can re-create the issue and later I'll explain why it's happening.

1. Create a new product.
2. Add a file feature to it and overwrite File Download Limit to 10.
3. Edit that feature and change the File Download Limit to 15.

Expected behavior:
Product Feature is updated.

Resulted behavior:
Duplicate and empty product feature is created.

Explanation into why:

uc_product_feature_save() is using db_affected_rows() to see if uc_product_feature entry has been updated and while it does get updated, the row does not change. In the database row pfid, nid, fid and description all remain the same. Thus I believe db_affected_rows() is returning 0...since nothing is really "affected". This is a minor issue with the database layer. Perhaps mysql specific.

To test this theory do something like change the description of the original product feature and you'll notice that a new entry is not created, instead the desired behavior happens. Why is this? Because the row is updated and "description" column changes, thus db_affected_rows() returns 1.

I've improved leprechau's patch to avoid an additional query that can be avoided in certain use cases.

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Ubercart Themes

Can also confirm this has not been resolved in -dev.

Good catch. Fortunately, this will be simpler in D7 because db_merge() takes care of this logic for us.

Committed.