Title: Hands-on Rust: question about get_component (page 295)
(feel free to respond. “You dug you’re own hole… good luck”)
I have something wrong implementing the “adventurer isn’t an Octopus” code. (Pretty sure it’s “wrong” somewhere else in my code, since I checked and rechecked this specific code several times, but I’m trying to sort out what I may have wrong)
In trying to track down what I’ve done wrong I’ve changed some of the code as follows: (mainly to break a few things out and get some visibility with ```println!()`` calls (adding line numbers to match against stack trace). (also, unfortunately, since this is panicking, it’s actually on picking up the first sword, so not exactly the scenario I’m trying to eventually fix)
40 items
41 .iter(ecs)
42 .filter(|(_entity, _item, &item_pos)| item_pos == player_pos)
43 .for_each(|(entity, _item, _item_pos)| {
44 commands.remove_component::<Point>(*entity);
45 commands.add_component(*entity, Carried(player));
46 if let Ok(e) = ecs.entry_ref(*entity) {
47 println!("Entity:{:#?}", e.archetype());
48 let is_weapon = e.get_component::<Weapon>().is_ok();
49 println!("Entity is weapon: {}", is_weapon);
50 <(Entity, &Carried, &Weapon)>::query()
51 .iter(ecs)
52 .filter(|(_, c, _)| {
53 let is_carried_by_player = c.0 == player;
54 println!(
55 "carried by player: {} {}",
56 is_carried_by_player, is_weapon
57 );
58 is_carried_by_player && is_weapon
59 })
60 .for_each(|(e, _, _)| {
61 println!("Remove Weapon Entity");
62 commands.remove(*e)
63 })
For which, I get the following console output:
Entity:Archetype {
index: ArchetypeIndex(
10,
),
entities: [
Entity(
25,
),
Entity(
24,
),
Entity(
22,
),
Entity(
47,
),
Entity(
46,
),
Entity(
45,
),
Entity(
44,
),
Entity(
40,
),
Entity(
35,
),
Entity(
33,
),
Entity(
59,
),
Entity(
58,
),
Entity(
54,
),
Entity(
48,
),
Entity(
79,
),
Entity(
76,
),
],
layout: EntityLayout {
components: [
ComponentTypeId {
type_id: TypeId {
t: 9061793563588654225,
},
name: "bracket_geometry::point::Point",
},
ComponentTypeId {
type_id: TypeId {
t: 8331237624739738968,
},
name: "dungeoncrawl::components::Render",
},
ComponentTypeId {
type_id: TypeId {
t: 18175530127838128523,
},
name: "dungeoncrawl::components::Name",
},
ComponentTypeId {
type_id: TypeId {
t: 14425425821466115813,
},
name: "dungeoncrawl::components::Item",
},
ComponentTypeId {
type_id: TypeId {
t: 1855713956641428298,
},
name: "dungeoncrawl::components::Damage",
},
ComponentTypeId {
type_id: TypeId {
t: 2499425021939920047,
},
name: "dungeoncrawl::components::Weapon",
},
],
component_constructors: [
0x0000000100f9f170,
0x0000000100f9fb50,
0x0000000100fa0200,
0x0000000100f9f2e0,
0x0000000100f9fcd0,
0x0000000100f9f260,
],
},
subscribers: Subscribers {
len: 0,
},
}
Entity is weapon: false
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: AccessDenied', /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/query/mod.rs:340:65
stack backtrace:
0: rust_begin_unwind
at /rustc/e1884a8e3c3e813aada8254edfa120e85bf5ffca/library/std/src/panicking.rs:495:5
1: core::panicking::panic_fmt
at /rustc/e1884a8e3c3e813aada8254edfa120e85bf5ffca/library/core/src/panicking.rs:92:14
2: core::option::expect_none_failed
at /rustc/e1884a8e3c3e813aada8254edfa120e85bf5ffca/library/core/src/option.rs:1268:5
3: core::result::Result<T,E>::unwrap
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/result.rs:973:23
4: legion::internals::query::Query<V,F>::iter_chunks_unchecked
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/query/mod.rs:340:24
5: legion::internals::query::Query<V,F>::iter_unchecked
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/query/mod.rs:484:9
6: legion::internals::query::Query<V,F>::iter
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/query/mod.rs:538:18
7: dungeoncrawl::systems::player_input::player_input::{{closure}}
at ./src/systems/player_input.rs:50:29
8: core::iter::traits::iterator::Iterator::for_each::call::{{closure}}
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:675:29
9: core::iter::adapters::filter_fold::{{closure}}
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/mod.rs:1071:44
10: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:269:13
11: core::iter::traits::iterator::Iterator::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:2023:21
12: <core::iter::adapters::flatten::FlattenCompat<I,U> as core::iter::traits::iterator::Iterator>::fold::flatten::{{closure}}
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/flatten.rs:332:30
13: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:269:13
14: core::iter::adapters::map_fold::{{closure}}
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/mod.rs:905:21
15: core::iter::traits::iterator::Iterator::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:2023:21
16: <core::iter::adapters::fuse::Fuse<I> as core::iter::adapters::fuse::FuseImpl<I>>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/fuse.rs:315:19
17: <core::iter::adapters::fuse::Fuse<I> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/fuse.rs:106:9
18: <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/mod.rs:945:9
19: <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/chain.rs:123:19
20: <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/chain.rs:120:19
21: <core::iter::adapters::flatten::FlattenCompat<I,U> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/flatten.rs:335:9
22: <core::iter::adapters::flatten::Flatten<I> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/flatten.rs:193:9
23: <core::iter::adapters::Filter<I,P> as core::iter::traits::iterator::Iterator>::fold
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/mod.rs:1135:9
24: core::iter::traits::iterator::Iterator::for_each
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:678:9
25: dungeoncrawl::systems::player_input::player_input
at ./src/systems/player_input.rs:40:17
26: dungeoncrawl::systems::player_input::player_input_system::{{closure}}
at ./src/systems/player_input.rs:10:1
27: <F as legion::internals::systems::system::SystemFn<R,Q>>::run
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/system.rs:220:9
28: <legion::internals::systems::system::System<R,Q,F> as legion::internals::systems::schedule::Runnable>::run_unsafe
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/system.rs:191:9
29: legion::internals::systems::schedule::Executor::run_recursive
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/schedule.rs:384:9
30: legion::internals::systems::schedule::Executor::run_systems::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/schedule.rs:353:34
31: <rayon::iter::for_each::ForEachConsumer<F> as rayon::iter::plumbing::Folder<T>>::consume
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/for_each.rs:47:9
32: <rayon::iter::filter::FilterFolder<C,P> as rayon::iter::plumbing::Folder<T>>::consume
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/filter.rs:123:24
33: rayon::iter::plumbing::Folder::consume_iter
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:179:20
34: rayon::iter::plumbing::Producer::fold_with
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:110:9
35: rayon::iter::plumbing::bridge_producer_consumer::helper
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:438:13
36: rayon::iter::plumbing::bridge_producer_consumer::helper::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:418:21
37: rayon_core::join::join_context::call_a::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:124:17
38: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:322:9
39: std::panicking::try::do_call
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:381:40
40: ___rust_try
41: std::panicking::try
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:345:19
42: std::panic::catch_unwind
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:396:14
43: rayon_core::unwind::halt_unwinding
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/unwind.rs:17:5
44: rayon_core::join::join_context::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:141:24
45: rayon_core::registry::in_worker
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:879:13
46: rayon_core::join::join_context
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:132:5
47: rayon::iter::plumbing::bridge_producer_consumer::helper
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:416:47
48: rayon::iter::plumbing::bridge_producer_consumer
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:397:12
49: <rayon::iter::plumbing::bridge::Callback<C> as rayon::iter::plumbing::ProducerCallback<I>>::callback
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:373:13
50: <rayon::range::Iter<usize> as rayon::iter::IndexedParallelIterator>::with_producer
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/range.rs:112:17
51: rayon::iter::plumbing::bridge
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/plumbing/mod.rs:357:12
52: <rayon::range::Iter<usize> as rayon::iter::ParallelIterator>::drive_unindexed
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/range.rs:88:17
53: <rayon::iter::filter::Filter<I,P> as rayon::iter::ParallelIterator>::drive_unindexed
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/filter.rs:46:9
54: rayon::iter::for_each::for_each
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/for_each.rs:12:5
55: rayon::iter::ParallelIterator::for_each
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.5.0/src/iter/mod.rs:369:9
56: legion::internals::systems::schedule::Executor::run_systems
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/schedule.rs:347:17
57: legion::internals::systems::schedule::Schedule::execute::{{closure}}::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/legion-0.3.1/src/internals/systems/schedule.rs:518:28
58: rayon_core::join::join::call::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:102:18
59: rayon_core::join::join_context::call_a::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:124:17
60: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:322:9
61: std::panicking::try::do_call
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:381:40
62: ___rust_try
63: std::panicking::try
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:345:19
64: std::panic::catch_unwind
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:396:14
65: rayon_core::unwind::halt_unwinding
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/unwind.rs:17:5
66: rayon_core::join::join_context::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/join/mod.rs:141:24
67: rayon_core::registry::Registry::in_worker_cold::{{closure}}::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:469:21
68: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute::call::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/job.rs:113:21
69: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:322:9
70: std::panicking::try::do_call
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:381:40
71: ___rust_try
72: std::panicking::try
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panicking.rs:345:19
73: std::panic::catch_unwind
at /Users/mike/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/panic.rs:396:14
74: rayon_core::unwind::halt_unwinding
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/unwind.rs:17:5
75: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/job.rs:119:38
76: rayon_core::job::JobRef::execute
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/job.rs:59:9
77: rayon_core::registry::WorkerThread::execute
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:753:9
78: rayon_core::registry::WorkerThread::wait_until_cold
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:730:17
79: rayon_core::registry::WorkerThread::wait_until
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:704:13
80: rayon_core::registry::main_loop
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:837:5
81: rayon_core::registry::ThreadBuilder::run
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:56:18
82: <rayon_core::registry::DefaultSpawn as rayon_core::registry::ThreadSpawn>::spawn::{{closure}}
at /Users/mike/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-core-1.9.0/src/registry.rs:101:20
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
So my questions are
1 - Am I completely misunderstanding what the archetype() function returns? It looks to me, like it says that the entity DOES have a Weapon component. However the e.get_component::<Weapon>().is_ok() call returns false
2 - Why am I getting an access denied panic (beyond the immediate "because you tried to unwrap() an Err (stupid)?
Item 7 on the stack trace points to my code, but it’s the <(Entity, &Carried, &Weapon)>::query() line and I’m not sure what about that could trigger a panic.