Permission Grid Causes People menu and its submenus to error out on PostgreSQL

I've been trying to dig into this. I put a ddebug_backtrace into user_role_load. The results of the backtrace:

18: user_role_load() (Array, 2 elements)
file (String, 29 characters ) modules/user/user.module:2911
args (Array, 1 element)
0 (String, 0 characters )
17: _menu_load_objects() (Array, 2 elements)
file (String, 21 characters ) includes/menu.inc:593
args (Array, 2 elements)
0 (Array, 23 elements)
path (String, 31 characters ) admin/people/permissions/grid/%
load_functions (String, 32 characters ) a:1:{i:4;s:14:"user_role_load";}
to_arg_functions (String, 0 characters )
access_callback (String, 11 characters ) user_access | (Callback) user_access();
access_arguments (String, 40 characters ) a:1:{i:0;s:22:"administer permissions";}
page_callback (String, 15 characters ) drupal_get_form | (Callback) drupal_get_form();
page_arguments (String, 70 characters ) a:2:{i:0;s:44:"permissions_grid_admin_node_perm...
delivery_callback (String, 0 characters )
fit (String, 2 characters ) 30
number_parts (String, 1 characters ) 5
context (String, 1 characters ) 1
tab_parent (String, 29 characters ) admin/people/permissions/grid
tab_root (String, 12 characters ) admin/people
title (String, 16 characters ) Permissions grid
title_callback (String, 1 characters ) t | (Callback) t();
title_arguments (String, 0 characters )
theme_callback (String, 0 characters )
theme_arguments (String, 6 characters ) a:0:{}
type (String, 3 characters ) 132
description (String, 29 characters ) Manage permissions for nodes.
position (String, 0 characters )
weight (String, 2 characters ) -7
include_file (String, 60 characters ) sites/all/modules/permission_grid/permissions_g...
1 (Array, 3 elements)
0 (String, 5 characters ) admin
1 (String, 6 characters ) people
2 (String, 11 characters ) permissions
16: _menu_translate() (Array, 2 elements)
file (String, 21 characters ) includes/menu.inc:761
args (Array, 3 elements)
0 (Array, 24 elements)
∞ (Recursion)
1 (Array, 3 elements)
0 (String, 5 characters ) admin
1 (String, 6 characters ) people
2 (String, 11 characters ) permissions
2 (Boolean) TRUE
15: menu_local_tasks() (Array, 2 elements)
file (String, 22 characters ) includes/menu.inc:1942
args (Array, 0 elements)
14: menu_tab_root_path() (Array, 2 elements)
file (String, 22 characters ) includes/menu.inc:2246
args (Array, 0 elements)
13: menu_get_active_help() (Array, 2 elements)
file (String, 22 characters ) includes/menu.inc:1710
args (Array, 0 elements)
12: system_block_view() (Array, 2 elements)
file (String, 33 characters ) modules/system/system.module:2087
args (Array, 1 element)
0 (String, 4 characters ) help
11: call_user_func_array() (Array, 1 element)
args (Array, 2 elements)
0 (String, 17 characters ) system_block_view | (Callback) system_block_view();
1 (Array, 1 element)
2 (String, 4 characters ) help
10: module_invoke() (Array, 2 elements)
file (String, 23 characters ) includes/module.inc:866
args (Array, 3 elements)
0 (String, 6 characters ) system | (Callback) system();
1 (String, 10 characters ) block_view
2 (String, 4 characters ) help
 9: _block_render_blocks() (Array, 2 elements)
file (String, 30 characters ) modules/block/block.module:881
args (Array, 1 element)
0 (Array, 1 element)
 8: block_list() (Array, 2 elements)
file (String, 30 characters ) modules/block/block.module:674
args (Array, 1 element)
 7: block_get_blocks_by_region() (Array, 2 elements)
file (String, 30 characters ) modules/block/block.module:318
args (Array, 1 element)
 6: block_page_build() (Array, 2 elements)
file (String, 30 characters ) modules/block/block.module:268
args (Array, 1 element)

Looks like the problem is in permissions_grid.admin.inc, but I haven't been able to figure out what yet.

From the backtrace, it doesn't look like it's happening in the form, but in menu code. From what I read of the backtrace, the last 'public' function called is menu_local_tasks (numbered 15 in the backtrace). The internal function _menu_load_object (numbered 17 in the backtrace) is being called with the $item argument an array decidedly pointing to permission_grid (include_file contains 'sites/all/modules/permission_grid/permissions_grid.admin.inc', path contains 'admin/people/permissions/grid/%', you can see plenty more in the traceback above).

For testing purposes, I created a new Drupal site, using PostgreSQL, and added only the Permissions Grid module, everything else just the standard Drupal install. Once that was done, just clicking on the People button in the task bar produced the error in the Issue Summary.

MySQL doesn't produce an error on this, because if you pass compare a string to a numeric field, MySQL will silently convert the string to a number. PostgreSQL and other databases are more picky. If you don't have access to PostgreSQL and want to reproduce the backtrace I have above, add these lines (temporarily, for testing purposes):

  if ($rid == '') {
    ddebug_backtrace();
  }

to the beginning of the user_role_load function in module/user/user.module, and then select the People link in the task bar. You'll get the same backtrace I put in comment #1 (except it will probably be easier to read), you just won't get the error I get on PostgreSQL). I did build a test MySQL-based Drupal site here, with Permissions Menu installed, and I get the backtrace. Note that $rid should be a number (being a Role Id number), so it being equal to an empty string is an error.

A bit more digging. This appears to have something to do with the autoloader wildcard %user_role in the second menu entry in permission_grid_menu. Evidently, this gets processed somehow before the form is even called (actually, it gets processed for admin/people/permissions or any submenu, apparently as part of menu handling), even if there is no part of the url corresponding to the wildcard. In the latter case, an empty string is passed as the role id, and PostgreSQL complains. You haven't seen this because MySQL doesn't complain about being handed an empty string for a number.