PathFindCells do not get reset after you reached the maximum limit of PathFindCells

[DrGoldFish1]

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

After we reach the PathFindCell limit and you continue to build more structures, then every building/scaffold that gets destroyed will leave there PathFind tiles behind, not getting reset. Once we go under the limit again and buildings get destroyed won`t leave PathFind tiles behind.

PathFind Tiles that are not cleaned up after a building is destroyed will permanently remove the ability for units to Pathfind over these tiles.

Buildings also sometimes generate Impassable tiles these will also be left behind, but these tiles will block the player from building a building on top of these impassable cells. while the other tiles the buildings leaves behind just blocks pathfinding but still allows for building contruction.

Bug related to #1984

Reproduction Steps

1. Start a game, Best to do this on a bigger map
2. Start placing big buildings to get this happening faster like a USA airfield. (place around 100 of these)
3. Once you reached the limit place extra scaffold then cancel them. If done correctly you will see Pathfindingtiles left behind

Additional Context

No response

[Skyaero42]

So the issue is the following code in PathfindCell::setTypeAsObstacle

	m_type = PathfindCell::CELL_OBSTACLE ;
	if (!m_info) {
		m_info = PathfindCellInfo::getACellInfo(this, pos);
		if (!m_info) {
			DEBUG_CRASH(("Not enough PathFindCellInfos in pool."));
			return false;
		}
	}

At some point, there are no PathFindCellInfos found (this is the cause of many issues with pathfinding, including stuck units). Therefore no m_info is created, but the cell (that the building coveres) is still set as obstacle.

When the building is removed, cells are cleared in

Bool PathfindCell::removeObstacle( Object *obstacle )
{
	if (m_type == PathfindCell::CELL_RUBBLE) {
		m_type = PathfindCell::CELL_CLEAR;
	}
	if (!m_info) return false;
	if (m_info->m_obstacleID != obstacle->getID()) return false;
	m_type = PathfindCell::CELL_CLEAR;
	m_info->m_obstacleID = INVALID_ID;
	releaseInfo();
	return true;
}

As m_info is null, m_type is never cleared.

Simple solution could be to move m_type = PathfindCell::CELL_CLEAR; before if (!m_info) return false;. This has been tested and works.

Another solution being worked on by @Mauller is to always initialize m_info for pathfindCells. This also resolves the issue (tested).