TYPO3.Flow

While working on some improvements for the Configuration subsystem, I stumbled over the following issue in arrayMergeRecursiveOverrule:

If the first element contains an array, and the second element contains a simple type at a certain position, the ORIGINAL array is used. I think that's a bug, preventing to reset arrays in configuration.

The following test demonstrates this:

 1'inputArray1' => array(
 2    'k1' => 'v1',
 3    'k2' => array(
 4        'k2.1' => 'v2.1'
 5    ),
 6),
 7'inputArray2' => array(
 8    'k2' => 'v2a',
 9    'k3' => 'v3'
10),
11// That's what SHOULD happen IMHO
12'expected' => array(
13    'k1' => 'v1',
14    'k2' => 'v2a',
15    'k3' => 'v3'
16)
17// That's what happens currently
18'actual' => array(
19    'k1' => 'v1',
20    'k2' => array(
21        'k2.1' => 'v2.1'
22    ),
23    'k3' => 'v3'
24)

This has drastical implications on configuration handling, as it makes it impossible to override an array with NULL:

// per-package settings.yaml
Foo:
  Bar:
    Baz: value

// global settings.yaml
Foo:
  Bar: NULL

// Expected:
array('Foo' => array('Bar' => NULL))

// Actual (right now)
array('Foo' => array('Bar' => array('Baz' => 'value')))