[TYPO3-commerce] RFC: #6634: Refactor tx_commerce_products get_attribute_matrix() and get_product_attribute_matrix()

[Christian Kuhn]

This is an SVN patch request.

Type: Refactoring

Branches: trunk

Forge issue ID: http://forge.typo3.org/issues/show/6634

Problem: get_attribute_matrix() and get_product_attribute_matrix() have 
tons of duplicate code, are messy and slow.

Solution: Rewrite the methods from scratch.

Notes:
The patch set is splitted into 4 parts:
- 6634_03_pre.diff is a pre patch to the existing methods to fix some 
minor issues and to make the result arrays a bit more predictable.
- 6634_03_main.diff is the main patch that introduces the new methods 
getAttributeMatrix() and getAttributeMatrixQuery().
- 6634_03_test.diff is a test patch that uses the old methods in 
parallel to the new methods and will output a debug if the result arrays 
differ.
- 6634_03_action.diff will be a follow-up patch to put the new methods 
into action and to deprecate the old ones.

The patches will be committed one at a time, so that each of it can be 
reverted easily afterwards, if messed something up.

How to test:
Apply patches _pre, _main and _test (find them attached to the forge 
issue), then test if the frontend produces debug output and compare the 
result arrays if so.

Many thanks to Dimitry König for early reviews and fixes!


Looking forward to your reviews
Christian