Indexing cron triggers sigsegv in apachesolr.module line 387

After releasing to the live server, the cron wouldn't index the documents anymore.
The cron would just die without leaving a message in the error logs.

I found that line 387 in apachesolr.module triggered a signal 11 (SIGSEGV) error in PHP 5.2.0-8+etch16.
PHP version 5.2.6-1+lenny4 (and higher) don't seem to suffer from this issue.

Backtrace: (sorry no php debug info)
Program terminated with signal 11, Segmentation fault.
#0 0x082beb03 in zend_object_store_get_object ()
(gdb) bt
#0 0x082beb03 in zend_object_store_get_object ()
#1 0x082bb75d in zend_objects_get_address ()
#2 0x082bcc60 in zend_std_read_property ()
#3 0x082f5ba4 in zend_get_zval_ptr_ptr ()
#4 0x082c0c88 in execute ()
#5 0x082d0c71 in execute ()
#6 0x082c0c88 in execute ()
#7 0x08297894 in zend_call_function ()
#8 0x082989da in call_user_function_ex ()
#9 0x081de97e in zif_call_user_func_array ()
#10 0x082d128f in execute ()
#11 0x082c0c88 in execute ()
#12 0x082d0c71 in execute ()
#13 0x082c0c88 in execute ()
#14 0x082d0c71 in execute ()
#15 0x082c0c88 in execute ()
#16 0x082a1e5c in zend_execute_scripts ()
#17 0x0825d0c2 in php_execute_script ()
#18 0x08330ffe in main ()

Since the backtrace mentions the zend_object_store_get_object, the array_walk_recursive function is called and the array on which this function is called contains objects, I figured that rewriting this line of code might solve the problem and it did!

I've attached my patch, but it need reviews because I didn't completely follow why the flattening of the array was called like this. See code below.

Questions I have are:

• Why is the temp data added to an object containing an array and not just an array?
• Is it even possible that the document array contains nested arrays? If not the code is redundant anyway.

code after patch:

// line 385
/**
 * Old code triggers signal 11 (SIGSEGV) in PHP 5.2.0-8+etch16.
 */
//  $tmp = (object) array('a' => array());
//  array_walk_recursive($documents, create_function('&$v, $k, &$t', '$t->a[] = $v;'), $tmp);
//  $documents = $tmp->a;

  // Flatten $documents
  $tmp = array();
  apachesolr_flatten_documents_array($documents, &$tmp);
  $documents = $tmp;

[...]

// line 431
/**
 * Function to flatten documents array recursively.
 * @param array $documents The documents array.
 * @param array $tmp The placeholder for the flat array.
 */
function apachesolr_flatten_documents_array($documents, &$tmp) {
  foreach ($documents AS $index => $item) {
    if (is_array($item)) {
      apachesolr_flatten_documents_array($item, $tmp);
    }
    else {
      $tmp[] = $item;
    }
  }
}