perf: visit fewer clauses during propagation (#66)

Cargo.toml

@@ -36,13 +36,12 @@ bitvec = "1.0.1"
 serde = { version = "1.0", features = ["derive"], optional = true }
 futures = { version = "0.3", default-features = false, features = ["alloc"] }
 event-listener = "5.3"
-
+indexmap = "2"
 tokio = { version = "1.37", features = ["rt"], optional = true }
 async-std = { version = "1.12", default-features = false, features = ["alloc", "default"], optional = true }
 
 [dev-dependencies]
 insta = "1.39.0"
-indexmap = "2"
 proptest = "1.2"
 tracing-test = { version = "0.2.4", features = ["no-env-filter"] }
 tokio = { version = "1.35.1", features = ["time", "rt"] }

src/conflict.rs

@@ -11,6 +11,7 @@ use petgraph::{
     Direction,
 };
 
+use crate::internal::arena::ArenaId;
 use crate::{
     internal::id::{ClauseId, InternalSolvableId, SolvableId, StringId, VersionSetId},
     runtime::AsyncRuntime,
@@ -52,11 +53,11 @@ impl Conflict {
         let unresolved_node = graph.add_node(ConflictNode::UnresolvedDependency);
 
         for clause_id in &self.clauses {
-            let clause = &solver.clauses.borrow()[*clause_id].kind;
+            let clause = &solver.clauses.kinds.borrow()[clause_id.to_usize()];
             match clause {
                 Clause::InstallRoot => (),
                 Clause::Excluded(solvable, reason) => {
-                    tracing::info!("{solvable:?} is excluded");
+                    tracing::trace!("{solvable:?} is excluded");
                     let package_node = Self::add_node(&mut graph, &mut nodes, *solvable);
                     let excluded_node = excluded_nodes
                         .entry(*reason)
@@ -76,7 +77,7 @@ impl Conflict {
                         unreachable!("The version set was used in the solver, so it must have been cached. Therefore cancellation is impossible here and we cannot get an `Err(...)`")
                     });
                     if candidates.is_empty() {
-                        tracing::info!(
+                        tracing::trace!(
                             "{package_id:?} requires {version_set_id:?}, which has no candidates"
                         );
                         graph.add_edge(
@@ -86,7 +87,7 @@ impl Conflict {
                         );
                     } else {
                         for &candidate_id in candidates {
-                            tracing::info!("{package_id:?} requires {candidate_id:?}");
+                            tracing::trace!("{package_id:?} requires {candidate_id:?}");
 
                             let candidate_node =
                                 Self::add_node(&mut graph, &mut nodes, candidate_id.into());

src/internal/arena.rs

@@ -107,9 +107,9 @@ impl<TId: ArenaId, TValue> Arena<TId, TValue> {
     pub fn get_two_mut(&mut self, a: TId, b: TId) -> (&mut TValue, &mut TValue) {
         let a_index = a.to_usize();
         let b_index = b.to_usize();
-        assert!(a_index < self.len());
-        assert!(b_index < self.len());
-        assert_ne!(a_index, b_index);
+        debug_assert!(a_index < self.len());
+        debug_assert!(b_index < self.len());
+        debug_assert_ne!(a_index, b_index);
         let (a_chunk, a_offset) = Self::chunk_and_offset(a_index);
         let (b_chunk, b_offset) = Self::chunk_and_offset(b_index);
         // SAFE: because we check that the indices are less than the length and that both indices do

src/internal/id.rs

@@ -77,12 +77,10 @@ impl ArenaId for VersionSetUnionId {
 #[cfg_attr(feature = "serde", serde(transparent))]
 pub struct SolvableId(pub u32);
 
-/// Internally used id for solvables that can also represent root and null.
+/// Internally used id for solvables that can also represent the root.
 #[repr(transparent)]
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug, Ord, PartialOrd)]
-pub(crate) struct InternalSolvableId(u32);
-
-const INTERNAL_SOLVABLE_NULL: u32 = u32::MAX;
+pub(crate) struct InternalSolvableId(pub u32);
 const INTERNAL_SOLVABLE_ROOT: u32 = 0;
 
 impl InternalSolvableId {
@@ -97,17 +95,9 @@ impl InternalSolvableId {
         self.0 == 0
     }
 
-    pub const fn null() -> Self {
-        Self(u32::MAX)
-    }
-
-    pub const fn is_null(self) -> bool {
-        self.0 == u32::MAX
-    }
-
     pub const fn as_solvable(self) -> Option<SolvableId> {
         match self.0 {
-            INTERNAL_SOLVABLE_NULL | INTERNAL_SOLVABLE_ROOT => None,
+            INTERNAL_SOLVABLE_ROOT => None,
             x => Some(SolvableId(x - 1)),
         }
     }
@@ -126,7 +116,6 @@ impl<'i, I: Interner> Display for DisplayInternalSolvable<'i, I> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self.id.0 {
             INTERNAL_SOLVABLE_ROOT => write!(f, "<root>"),
-            INTERNAL_SOLVABLE_NULL => write!(f, "<null>"),
             x => {
                 write!(f, "{}", self.interner.display_solvable(SolvableId(x - 1)))
             }

src/internal/mapping.rs

@@ -50,7 +50,7 @@ impl<TId: ArenaId, TValue> Mapping<TId, TValue> {
     }
 
     /// Insert into the mapping with the specific value
-    pub fn insert(&mut self, id: TId, value: TValue) {
+    pub fn insert(&mut self, id: TId, value: TValue) -> Option<TValue> {
         let idx = id.to_usize();
         let (chunk, offset) = Self::chunk_and_offset(idx);
 
@@ -59,9 +59,10 @@ impl<TId: ArenaId, TValue> Mapping<TId, TValue> {
             self.chunks
                 .resize_with(chunk + 1, || std::array::from_fn(|_| None));
         }
-        self.chunks[chunk][offset] = Some(value);
+        let previous_value = self.chunks[chunk][offset].replace(value);
         self.len += 1;
         self.max = self.max.max(idx);
+        previous_value
     }
 
     /// Get a specific value in the mapping with bound checks