'Not unique table/alias' warning

Somehow the attachment didn't get sent along.

The problem seems to extend a bit further than what I anticipated.
When more than two instances of the same join are used, there were still unique table errors.

I came to the conclusion that array_merge did not merge the query arrays the way they should be merged.

For instance, the query->joins array:

query1 => Array (
    ...,
    [joins] => Array (
            [relativity_parent] => Array (
                    [2] => Array (
                            [left] => Array (
                                    [table] => node
                                    [field] => nid
                                    [alias] => v61
                                )
                            [right] => Array (
                                    [field] => parent_nid
                                )
                            [type] => inner
                        )
                )
            [node] => ...

array_merge'd with (notice the different index of the relativity_parent join -- 1 vs 2):

query2 => Array (
    ...,
    [joins] => Array (
            [relativity_parent] => Array (
                    [1] => Array (
                            [left] => Array (
                                    [table] => node
                                    [field] => nid
                                    [alias] => v62
                                )
                            [right] => Array (
                                    [field] => parent_nid
                                )
                            [type] => inner
                        )
                )
            [node] => ...

would result in:

query1 => Array (
    ...,
    [joins] => Array (
            [relativity_parent] => Array (
                    [1] => Array (
                            [left] => Array (
                                    [table] => node
                                    [field] => nid
                                    [alias] => v62
                                )
                            [right] => Array (
                                    [field] => parent_nid
                                )
                            [type] => inner
                        )
                )
            [node] => ...

While this should have been:

query1 => Array (
    ...,
    [joins] => Array (
            [relativity_parent] => Array (
                    [2] => Array (
                            [left] => Array (
                                    [table] => node
                                    [field] => nid
                                    [alias] => v61
                                )
                            [right] => Array (
                                    [field] => parent_nid
                                )
                            [type] => inner
                        ),
                    [1] => Array (
                            [left] => Array (
                                    [table] => node
                                    [field] => nid
                                    [alias] => v62
                                )
                            [right] => Array (
                                    [field] => parent_nid
                                )
                            [type] => inner
                        )
                )
            [node] => ...

Regarding the query2->tables array:

    [tables] => Array
        (
            [relativity_parent] => 2
            [v62node] => 1
        )

merged with query1->tables using array_merge:

    [tables] => Array
        (
            [relativity_parent] => 1
            [v61node] => 1
        )

results in:

    [tables] => Array
        (
            [v62node] => 1
            [relativity_parent] => 1
            [v61node] => 1
        )

while it should result in:

    [tables] => Array
        (
            [relativity_parent] => 2
            [v62node] => 1
            [v61node] => 1


        )

Since the different arrays in the query object are built up in different ways, using simple array_merge will mess things up quite a bunch.

The code I'v used to fix all my problems (this is not really patch-worthy in its current form) is as follows:

function views_fusion_query_merge(&$query1, &$query2) {
  
  if ($query2->groupby && !$query1->groupby) {
    $query1->groupby = $query2->groupby;
  }
  else {
    //add an alias to the nid field
    $query2->fields[0] .= ' AS '. $query2->use_alias_prefix . 'node_nid';
  }
  
  //if query2 is set to be distinct, set query1 to distinct
  if ($query2->distinct) {
    $query1->set_distinct();
  } 

  $query1->tablequeue = array_merge($query1->tablequeue, $query2->tablequeue);
  // Joins
  foreach ($query2->joins as $table => $joins) {
    foreach ($joins as $num => $join) {
      $query1->joins[$table][$num] = $join;
    }
  }
  $query1->fields = array_merge($query1->fields, $query2->fields);
  $query1->where = array_merge($query1->where, $query2->where); 
  $query1->where_args = array_merge($query1->where_args, $query2->where_args);
  $query1->orderby = array_merge($query1->orderby, $query2->orderby);  
  // Tables
  foreach ($query2->tables as $table => $num) {
    $query1->tables[$table] = (isset($query1->tables[$table]) ? max($query1->tables[$table], $num) : $num);
  }
}

Would like to hear your thoughts on this.

Also, in views_fusion_views_merge there's a missing line:

$view1->filter = array_merge($view1->filter, $view2->filter);

which caused my exposed filters to assume values of other (non-exposed) filters. Simply because the filter array was missing a bunch of values.