[Merged by Bors] - Conversion of ResMut and NonSendMut to Mut

crates/bevy_ecs/src/change_detection.rs

@@ -185,6 +185,17 @@ change_detection_impl!(ResMut<'a, T>, T, Resource);
 impl_into_inner!(ResMut<'a, T>, T, Resource);
 impl_debug!(ResMut<'a, T>, Resource);
 
+impl<'a, T: Resource> From<ResMut<'a, T>> for Mut<'a, T> {
+    /// Convert this `ResMut` into a `Mut`. This allows keeping the change-detection feature of `Mut`
+    /// while losing the specificity of `ResMut` for resources.
+    fn from(other: ResMut<'a, T>) -> Mut<'a, T> {
+        Mut {
+            value: other.value,
+            ticks: other.ticks,
+        }
+    }
+}
+
 /// Unique borrow of a non-[`Send`] resource.
 ///
 /// Only [`Send`] resources may be accessed with the [`ResMut`] [`SystemParam`](crate::system::SystemParam). In case that the
@@ -206,6 +217,17 @@ change_detection_impl!(NonSendMut<'a, T>, T,);
 impl_into_inner!(NonSendMut<'a, T>, T,);
 impl_debug!(NonSendMut<'a, T>,);
 
+impl<'a, T: Resource> From<NonSendMut<'a, T>> for Mut<'a, T> {
+    /// Convert this `NonSendMut` into a `Mut`. This allows keeping the change-detection feature of `Mut`
+    /// while losing the specificity of `NonSendMut`.
+    fn from(other: NonSendMut<'a, T>) -> Mut<'a, T> {
+        Mut {
+            value: other.value,
+            ticks: other.ticks,
+        }
+    }
+}
+
 /// Unique mutable borrow of an entity's component
 pub struct Mut<'a, T> {
     pub(crate) value: &'a mut T,
@@ -286,7 +308,9 @@ impl std::fmt::Debug for MutUntyped<'_> {
 mod tests {
     use crate::{
         self as bevy_ecs,
-        change_detection::{CHECK_TICK_THRESHOLD, MAX_CHANGE_AGE},
+        change_detection::{
+            ComponentTicks, Mut, NonSendMut, ResMut, Ticks, CHECK_TICK_THRESHOLD, MAX_CHANGE_AGE,
+        },
         component::Component,
         query::ChangeTrackers,
         system::{IntoSystem, Query, System},
@@ -296,6 +320,8 @@ mod tests {
     #[derive(Component)]
     struct C;
 
+    struct R; // Resource
+
     #[test]
     fn change_expiration() {
         fn change_detected(query: Query<ChangeTrackers<C>>) -> bool {
@@ -382,4 +408,52 @@ mod tests {
             assert!(ticks_since_change == MAX_CHANGE_AGE);
         }
     }
+
+    #[test]
+    fn mut_from_res_mut() {
+        let mut component_ticks = ComponentTicks {
+            added: 1,
+            changed: 2,
+        };
+        let ticks = Ticks {
+            component_ticks: &mut component_ticks,
+            last_change_tick: 3,
+            change_tick: 4,
+        };
+        let mut res = R {};
+        let res_mut = ResMut {
+            value: &mut res,
+            ticks,
+        };
+
+        let into_mut: Mut<R> = res_mut.into();
+        assert_eq!(1, into_mut.ticks.component_ticks.added);
+        assert_eq!(2, into_mut.ticks.component_ticks.changed);
+        assert_eq!(3, into_mut.ticks.last_change_tick);
+        assert_eq!(4, into_mut.ticks.change_tick);
+    }
+
+    #[test]
+    fn mut_from_non_send_mut() {
+        let mut component_ticks = ComponentTicks {
+            added: 1,
+            changed: 2,
+        };
+        let ticks = Ticks {
+            component_ticks: &mut component_ticks,
+            last_change_tick: 3,
+            change_tick: 4,
+        };
+        let mut res = R {};
+        let non_send_mut = NonSendMut {
+            value: &mut res,
+            ticks,
+        };
+
+        let into_mut: Mut<R> = non_send_mut.into();
+        assert_eq!(1, into_mut.ticks.component_ticks.added);
+        assert_eq!(2, into_mut.ticks.component_ticks.changed);
+        assert_eq!(3, into_mut.ticks.last_change_tick);
+        assert_eq!(4, into_mut.ticks.change_tick);
+    }
 }