Use smallvec crate in pubgrub

Author: x-hgg-x

Cargo.lock

@@ -28,6 +28,7 @@ log = "0.4.22" # for debug logs in tests
 priority-queue = "2.1.1"
 rustc-hash = ">=1.0.0, <3.0.0"
 serde = { version = "1.0", features = ["derive"], optional = true }
+smallvec = { version = "1.13.2", features = ["union"] }
 thiserror = "1.0"
 version-ranges = { version = "0.1.0", path = "version-ranges" }
 

Cargo.toml

@@ -5,10 +5,12 @@
 
 use std::sync::Arc;
 
+use smallvec::SmallVec;
+
 use crate::{
     internal::{
         Arena, DecisionLevel, IncompDpId, Incompatibility, PartialSolution, Relation,
-        SatisfierSearch, SmallVec,
+        SatisfierSearch,
     },
     DependencyProvider, DerivationTree, Map, Package, PackageArena, Set, Term, Version, VersionSet,
 };
@@ -25,7 +27,7 @@ pub(crate) struct State<DP: DependencyProvider> {
     /// All incompatibilities expressing dependencies,
     /// with common dependents merged.
     #[allow(clippy::type_complexity)]
-    merged_dependencies: Map<(Package, Package), SmallVec<IncompDpId<DP>>>,
+    merged_dependencies: Map<(Package, Package), SmallVec<[IncompDpId<DP>; 4]>>,
 
     /// Partial solution.
     /// TODO: remove pub.
@@ -37,7 +39,7 @@ pub(crate) struct State<DP: DependencyProvider> {
     /// This is a stack of work to be done in `unit_propagation`.
     /// It can definitely be a local variable to that method, but
     /// this way we can reuse the same allocation for better performance.
-    unit_propagation_buffer: SmallVec<Package>,
+    unit_propagation_buffer: Vec<Package>,
 }
 
 impl<DP: DependencyProvider> State<DP> {
@@ -54,7 +56,7 @@ impl<DP: DependencyProvider> State<DP> {
             incompatibilities,
             partial_solution: PartialSolution::empty(),
             incompatibility_store,
-            unit_propagation_buffer: SmallVec::Empty,
+            unit_propagation_buffer: Vec::new(),
             merged_dependencies: Map::default(),
         }
     }

src/internal/core.rs

@@ -7,11 +7,9 @@ mod core;
 mod incompatibility;
 mod partial_solution;
 mod small_map;
-mod small_vec;
 
 pub(crate) use arena::{Arena, Id};
 pub(crate) use core::State;
 pub(crate) use incompatibility::{IncompDpId, IncompId, Incompatibility, Relation};
 pub(crate) use partial_solution::{DecisionLevel, PartialSolution, SatisfierSearch};
 pub(crate) use small_map::SmallMap;
-pub(crate) use small_vec::SmallVec;

src/internal/mod.rs

@@ -8,9 +8,10 @@ use std::hash::BuildHasherDefault;
 
 use priority_queue::PriorityQueue;
 use rustc_hash::FxHasher;
+use smallvec::{smallvec, SmallVec};
 
 use crate::{
-    internal::{Arena, IncompDpId, IncompId, Incompatibility, Relation, SmallMap, SmallVec},
+    internal::{Arena, IncompDpId, IncompId, Incompatibility, Relation, SmallMap},
     DependencyProvider, FxIndexMap, Package, PackageArena, SelectedDependencies, Term, Version,
     VersionSet,
 };
@@ -97,7 +98,7 @@ impl<'a, DP: DependencyProvider> Display for PartialSolutionDisplay<'a, DP> {
 struct PackageAssignments<M: Clone + Debug + Display> {
     smallest_decision_level: DecisionLevel,
     highest_decision_level: DecisionLevel,
-    dated_derivations: SmallVec<DatedDerivation<M>>,
+    dated_derivations: SmallVec<[DatedDerivation<M>; 1]>,
     assignments_intersection: AssignmentsIntersection,
 }
 
@@ -298,7 +299,7 @@ impl<DP: DependencyProvider> PartialSolution<DP> {
                 v.insert(PackageAssignments {
                     smallest_decision_level: self.current_decision_level,
                     highest_decision_level: self.current_decision_level,
-                    dated_derivations: SmallVec::One([dated_derivation]),
+                    dated_derivations: smallvec![dated_derivation],
                     assignments_intersection: AssignmentsIntersection::derivations(term),
                 });
             }