Do we also need to handle module id -1 (_AM_SYSTEM_BLOCKS_TOPPAGE)

Good point! Any code suggestions? Could you make PR?

there is a problem: if we allow module id -1 or module id 0 without checking the module activeness then we have the same as in past time (blocks of inactive modules causing problems)
I will check it and try to find a solution

I haven't looked into blocks for a while. Maybe we are handling module_id -1 correctly.

For the tables, is:

• newblocks b ,is the blocks table
• block_module_link m ,links the blocks to which module, and page they are shown
• modules mo ,is the modules table.

b.mid of 0 are custom/new blocks?
m.module_id is what module the block should appear on. (specific module, all pages, top page)

the new code is fine. we have two possibilities:

1. custom block, which is active ( WHERE b.isactive =' . $isactive . ' AND (mo.isactive =' . $isactive . ' OR b.mid = 0)';
2. system or user block, which is active and where the module itself is active ( WHERE b.isactive =' . $isactive . ' AND (mo.isactive =' . $isactive . ' OR b.mid = 0)';

at this stage it doesn't matter where it is to show (top page, all pages,...) because this is handled by the next lines

How about this:

        $sql = 'SELECT b.* FROM ' . $db->prefix('newblocks') . ' b ' .
               'JOIN ' . $db->prefix('block_module_link') . ' m ON m.block_id = b.bid ' .
               'LEFT JOIN ' . $db->prefix('modules') . ' mo ON mo.mid = b.mid ' .
               'WHERE b.isactive = ' . $isactive . ' ' .
               'AND ( (b.mid = 0) OR (b.mid > 0 AND mo.mid IS NOT NULL AND mo.isactive = ' . $isactive . ') )';

This ensures:

• Custom blocks (b.mid = 0) are always allowed, regardless of the modules table.
• Module-specific blocks (b.mid > 0) only appear if their module exists (mo.mid IS NOT NULL) and is active (mo.isactive = 1).

Fixes the inactive module issue: blocks tied to inactive modules won’t show, even if m.module_id = -1 or 0.

more in detail, but it is very fine :)

This request is crazy !!!
You've got a hell of level !