Fix a crash when npc tries to heal horse-mounted player #40025
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ZhilkinSerg
added
NPC / Factions
jbytheway
reviewed
Apr 30, 2020
src/game.cpp
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Comment on lines
4713
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4723
| if( const shared_ptr_fast<monster> mon_ptr = critter_tracker->find( critter.pos() ) ) { | ||
| return std::dynamic_pointer_cast<T>( mon_ptr ); | ||
| } | ||
| if( static_cast<const Creature *>( &critter ) == static_cast<const Creature *>( &u ) ) { | ||
| // u is not stored in a shared_ptr, but it won't go out of scope anyway | ||
| return std::dynamic_pointer_cast<T>( u_shared_ptr ); | ||
| } | ||
| for( auto &cur_mon : critter_tracker->get_monsters_list() ) { | ||
| if( static_cast<const Creature *>( cur_mon.get() ) == static_cast<const Creature *>( &critter ) ) { | ||
| return std::dynamic_pointer_cast<T>( cur_mon ); | ||
| } | ||
| } |
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I don't think this is a good solution; it makes this function O(n) in the number of monsters, which could have a bad performance impact.
I think it would also work to instead replace the initial if block with:
if( const shared_ptr_fast<monster> mon_ptr = critter_tracker->find( critter.pos() ) ) {
if( shared_ptr<T> result = std::dynamic_pointer_cast<T>( mon_ptr ) ) {
return result;
}
}
Then for this case (player riding monster) the cast would fail and the code would fall through to the next check and succeed in returning the player.
This was referenced May 3, 2020
Merged
kevingranade
pushed a commit
that referenced
this pull request
Jun 18, 2020
…layer Co-authored-by: Qrox <[email protected]>
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Summary
SUMMARY: Bugfixes "Fix a crash when npc tries to heal horse-mounted player."
Purpose of change
Fixes #40001.
game::shared_fromassumed that the player cannot be at the same location as a monster, which no longer holds now that mounting creatures is possible. If the player is mounted on a creatureg->shared_from( g->u )returns the mounted creature, sopatientinnpc::execute_actionbecomes nullptr after dynamic casting it toplayer.Describe the solution
In
npc_execute_action, checkpatientis not null before dereferencing it.In
game::shared_from, checkcritteris a monster/npc before searching for its shared pointer, and only return the shared pointer if it refers to the same object ascritter.Testing
Loaded the save from #40001 and it no longer crashed. NPCs now also heal the player when they are mounted.
Additional context
Should probably be backported to 0.E.