Prevent segfault on unload_activity_actor #70575
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Prevents segfault that previously happened when pouring liquid to ground from AIM using "examine" menu. Previous segfault being fixed: ``` #0 __gnu_cxx::__atomic_add_dispatch () at /usr/include/c++/13/ext/atomicity.h:111 CleverRaven#1 std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_add_ref_copy () at /usr/include/c++/13/bits/shared_ptr_base.h:152 CleverRaven#2 0x00005652b2df5540 in std::shared_ptr<item_location::impl>::shared_ptr () at /usr/include/c++/13/bits/shared_ptr.h:204 CleverRaven#3 item_location::item_location () at src/item_location.h:30 CleverRaven#4 item_location::impl::item_in_container::item_in_container () at src/item_location.cpp:612 CleverRaven#5 item_location::item_location () at src/item_location.cpp:767 CleverRaven#6 0x00005652b27fa6b1 in unload_activity_actor::unload () at src/activity_actor.cpp:3232 CleverRaven#7 0x00005652b32eed69 in player_activity::do_turn () at src/player_activity.cpp:383 CleverRaven#8 0x00005652b2b553e7 in do_turn () at src/do_turn.cpp:487 CleverRaven#9 0x00005652b25ea589 in main () at src/main.cpp:798 ``` The problem before was that the reference to `target` in `unload_activity_actor::unload` was an invalid reference. This was caused by: 1. `unload_activity_actor::finish` calls `act.set_to_null()`. 2. That sets the player activity to `null` type (=no current activity) 3. `unload_activity_actor::unload` is `static`, and takes `target` as a reference. 4. `::unload` calls `Character::add_or_drop_with_msg` which leads to call chain: `liquid_handler::consume_liquid` -> `get_liquid_target` -> `choose_adjacent` -> `choose_direction` -> `temp_hide_advanced_inv` -> `advanced_inventory::temp_hide` -> `advanced_inventory::do_return_entry` 5. `advanced_inventory::do_return_entry` assigns a new `ACT_ADV_INVENTORY` activity. This invalidates the previous `unload_activity_actor` because of pt 2 above. 6. When static method `unload_activity_actor::unload` resumes after its call to `add_or_drop_with_msg`, the reference to `target` is invalid because of pt 5. This commit attempt to fix the issue with invalidated `target` reference by copying its value before invalidating the activity.
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Ew that set to null blows away the actor. |
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Summary
Bugfixes "Prevent segfault on unload_activity_actor"
Purpose of change
Describe the solution
Previous segfault being fixed:
The problem before was that the reference to
targetinunload_activity_actor::unloadwas an invalid reference. This was caused by:unload_activity_actor::finishcallsact.set_to_null().nulltype (=no current activity)unload_activity_actor::unloadisstatic, and takestargetas a reference.::unloadcallsCharacter::add_or_drop_with_msgwhich leads to call chain:liquid_handler::consume_liquid->get_liquid_target->choose_adjacent->choose_direction->temp_hide_advanced_inv->advanced_inventory::temp_hide->advanced_inventory::do_return_entryadvanced_inventory::do_return_entryassigns a newACT_ADV_INVENTORYactivity. This invalidates the previousunload_activity_actorbecause of pt 2 above.unload_activity_actor::unloadresumes after its call toadd_or_drop_with_msg, the reference totargetis invalid because of pt 5.This commit attempt to fix the issue with invalidated
targetreference by copying its value before invalidating the activity.Describe alternatives you've considered
Testing
Additional context