Since I had a request for the feature and noticed that it is used by Product Extra Fields 2.1 I have upgraded this contribution to allow an extra product field to be available only for products that exist in certain categories. Since products can exist in multiple categories the contribution checks all categories containing the product being edited to see if it is one of the categories for which the extra field is available. If none match then the field is hidden from view so that data can't be entered into the field for the product. By default extra fields apply to all categories. If the extra field is available for a category it is also automatically available for every subcategory found underneath that category no matter have far down it is nested.

The complete contribution is enclosed. For new installations the install instructions have been updated for the new feature. Upgrade instructions are included for those upgrading from an earlier version of Extra Product Fields. For those converting from the Product Extra Fields contribution the conversion program has been updated to accomodate the version 2.1 feature that applies fields to specific categories. Extra fields created from older versions of Product Extra Fields will be set as available to all categories.

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