MageKing17 98713dadc1 Avoid calling asteroid_add_target() in FRED. ...

PR #5058 made `count_incident_asteroids()` use `Asteroid_obj_list` instead of `obj_used_list`; a perfectly sensible change in and of itself. However, PR #4827 had previously made `asteroid_obj_list_init()` only be called if FRED wasn't running (presumably because of the iteration through `Asteroid_objs` to clear flags, which is wasted effort in FRED). The problem is that without `list_init()` being called on `Asteroid_obj_list`, its `prev` and `next` were `nullptr` instead of linking back to itself, which means the beginning of the list and the end of the list were no longer considered the same (the iterator's `begin()` calls `GET_FIRST(head)`, which is effectively `head->next`, while `end()` calls `END_OF_LIST(head)`, which is effectively just `head`). This meant that iterating over `list_range(Asteroid_obj_list)` was returning `nullptr` as the first element of the list, and trying to dereference that would cause a crash. This was still not a problem in and of itself, as long as nothing tried to iterate over `Asteroid_obj_list` while FRED was running, which theoretically shouldn't be necessary...

PR #3704 changed mission parsing so that when parsing a ship with a name that matches one of the `Asteroid_field.target_names`, it would call `asteroid_add_target()` to initialize the relevant data for the asteroid field to fling asteroids at that ship. `asteroid_add_target()` calls `count_incident_asteroids()`, which (since PR #5058) iterates over `Asteroid_obj_list`, causing a crash due to dereferencing a null pointer on any mission that defines `$Asteroid Targets:` (and then actually has such a target be parsed).

While this could be solved by unconditionally initializing `Asteroid_obj_list`, there's really no need to do anything with `Asteroid_obj_list` in FRED, so instead the `asteroid_add_target()` call has been gated behind a `!Fred_running` check, and `Assertion()`s have been added to make sure `Asteroid_obj_list` has been initialized at the beginning of any function that does anything with it (besides initialize it), to catch similar problems in the future.

Fixes #5092.

2023-01-09 06:43:58 -08:00

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asteroid.cpp

Avoid calling asteroid_add_target() in FRED.

2023-01-09 06:43:58 -08:00

asteroid.h

Asteroid/Debris cleanup + Modular asteroids table (#4870)

2022-12-11 19:29:23 -05:00