Garrisons become clearable by any area of effect weapon if the map has multiple borders and has shrunk instead of expanded

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Prerequisites

• I have searched for similar issues and confirmed this is not a duplicate

Game Version

• Command & Conquer Generals
• Command & Conquer Generals: Zero Hour
• Other (please specify below)

Bug Description

Relates to: #1287
Garrisoned structures normally can only be cleared by dedicated weapons. If this bug is present, all weapons that deal area of effect damage (e.g. Scud Launchers, Inferno Cannons, MiGs, all radiation and toxin pools) can suddenly damage occupants of garrisons directly.

This bug is present in both vGEN and ZH, but is normally not seen because no retail maps in either vGEN or ZH use map borders to shrink the map, only to expand it. Custom and fan-made missions do encounter this.

Reproduction Steps

1. Make a map with multiple borders; each border must be of different size.
2. Start the map on a border larger than other ones, and garrison any structure
3. Resize the map to a smaller border with scripts
4. Attack the garrison with any AoE weapon
5. The occupants will die

I have included bug reproduction maps for both vGEN and ZH below. I recommend testing the ZH one first because it explains every step. The vGEN one is there just to prove the point.
I recommend running the maps with scriptdebugger to see what is going on.

bordersTestZH.zip

borderTestGEN.zip

Additional Context

While this issue is closely related to #1287 , there is a fundamental difference: this issue affects all garrisoned structures, while 1287 affects only specific garrisons that were previously off-map.

I have performed additional tests:

• This bug works regardless of the type of garrison. Structures that cannot be cleared normally (e.g. China Bunker, Internet Centers) also clear out when targeted.
• I have tested this with Tunnel Networks as well. These seem to be unaffected, but I am not 100% certain. Best to check as well.
• Overlord Bunkers are effected as well, but it takes a bit more effort to achieve the bug because the Overlord Bunkers can't be targeted directly. You need a big AoE to do it. Nuke cannons, Scud Launchers or similar will work. Moreover, once the infantry inside are dead, they still show up as occupants but cannot be evacuated.
• This link will show Marakar playtesting a map for Contra mod. The important timestamps are approximately 07:50 (the map expands and hackers stop hacking -> notice the hacker money flow stop) and 08:30 (Marakar notices the bugged hackers and evacuates Internet Centers, only for the hackers to die instantly. It is clear that the map expansion causes this, since it is at that exact moment Hackers "die" inside the Internet Centers.