In my pathfinding routine, I simply check that the End (and Start) positions are valid. if not, no search will be performed.

Quote: Original post by Bob III
An odd effect is that more effort will be spent to navigate a thicker obstacle than a thin one.

Obviously, you don't want your agent moving away from his destination. If the final path node is farther from the destination than he started, then you can reject the path altogether and assume he's as close to the destination as he's going to get. If the final node is closer but there are other nodes closer to the destination than the final one, you can stop at one of those instead.