refactor(runtime): use enumset for frame demand reasons

Cargo.toml

@@ -174,6 +174,7 @@ rustc-hash = "2"
 hashbrown = "0.17"
 num_enum = "0.7.6"
 enum_dispatch = "0.3.13"
+enumset = "1.1.14"
 strum = { version = "0.28", features = ["derive"] }
 unicode_names2 = "3.1.0"
 unicode-script = "0.5"

crates/neomacs-display-runtime/Cargo.toml

@@ -37,6 +37,7 @@ tracing.workspace = true
 tracing-subscriber.workspace = true
 serde_json.workspace = true
 strum.workspace = true
+enumset.workspace = true
 num_enum.workspace = true
 thiserror.workspace = true
 bitflags.workspace = true

crates/neomacs-display-runtime/src/render_thread/frame_sched.rs

@@ -135,7 +135,8 @@ macro_rules! demand_reasons {
         // Interface variants/fields defined by the scheduling plan; consumed as
         // later stages migrate effects onto the coordinator.
         #[allow(dead_code)]
-        #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, enumset::EnumSetType)]
+        #[enumset(no_super_impls, no_ops)]
         pub(crate) enum DemandReason {
             $($(#[$variant_meta])* $variant,)+
         }
@@ -221,43 +222,8 @@ impl DemandReason {
 
 /// Set of [`DemandReason`]s, carried by value on a [`FramePlan`] so a frame can
 /// be attributed to what asked for it ("why did this present happen?").
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub(crate) struct DemandReasonSet(u32);
-
-impl DemandReasonSet {
-    pub(crate) const fn empty() -> Self {
-        DemandReasonSet(0)
-    }
-
-    fn insert(&mut self, reason: DemandReason) {
-        self.0 |= 1 << reason.index();
-    }
-
-    pub(crate) fn contains(self, reason: DemandReason) -> bool {
-        self.0 & (1 << reason.index()) != 0
-    }
-
-    pub(crate) fn is_empty(self) -> bool {
-        self.0 == 0
-    }
-
-    /// Reasons in [`DemandReason::ALL`] order.
-    pub(crate) fn iter(self) -> impl Iterator<Item = DemandReason> {
-        DemandReason::ALL
-            .into_iter()
-            .filter(move |r| self.contains(*r))
-    }
-}
-
-impl FromIterator<DemandReason> for DemandReasonSet {
-    fn from_iter<I: IntoIterator<Item = DemandReason>>(iter: I) -> Self {
-        let mut set = DemandReasonSet::empty();
-        for reason in iter {
-            set.insert(reason);
-        }
-        set
-    }
-}
+/// Iteration follows declaration order, matching [`DemandReason::ALL`].
+pub(crate) type DemandReasonSet = enumset::EnumSet<DemandReason>;
 
 /// A declaration that pixels need to change, with reason, scope, and cadence.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]

crates/neomacs-display-runtime/src/render_thread/tests/frame_sched_test.rs

@@ -1253,3 +1253,20 @@ fn servicing_twice_at_one_timestamp_is_idempotent() {
         "nothing ripe survives one service"
     );
 }
+
+#[test]
+fn demand_reason_sets_deduplicate_and_iterate_in_declaration_order() {
+    let reasons: DemandReasonSet = DemandReason::ALL
+        .into_iter()
+        .rev()
+        .chain(DemandReason::ALL)
+        .collect();
+    assert!(reasons.iter().eq(DemandReason::ALL));
+    for reason in DemandReason::ALL {
+        assert!(reasons.contains(reason), "missing {reason:?}");
+    }
+    let empty = DemandReasonSet::default();
+    assert!(empty.is_empty());
+    assert!(empty.iter().next().is_none());
+    assert!(!empty.contains(DemandReason::EditorCommit));
+}