Add bench for backtracking

Cargo.toml

@@ -24,7 +24,8 @@ include = ["Cargo.toml", "LICENSE", "README.md", "src/**", "tests/**", "examples
 
 [dependencies]
 indexmap = "2.6.0"
-log = "0.4.22" # for debug logs in tests
+# for debug logs in tests
+log = "0.4.22"
 priority-queue = "2.1.1"
 rustc-hash = ">=1.0.0, <3.0.0"
 serde = { version = "1.0", features = ["derive"], optional = true }
@@ -42,6 +43,10 @@ version-ranges = { version = "0.1.0", path = "version-ranges", features = ["prop
 [features]
 serde = ["dep:serde", "version-ranges/serde"]
 
+[[bench]]
+name = "backtracking"
+harness = false
+
 [[bench]]
 name = "large_case"
 harness = false

benches/backtracking.rs

@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: MPL-2.0
+
+//! This bench monitors the performance of backtracking and term intersection.
+//!
+//! Dependencies are constructed in a way that all versions need to be tested before finding a solution.
+
+use criterion::*;
+use pubgrub::OfflineDependencyProvider;
+use version_ranges::Ranges;
+
+/// This benchmark is a simplified reproduction of one of the patterns found in the `solana-*` crates from Cargo:
+/// * `solana-archiver-lib v1.1.12` depends on many layers of other solana crates with req `>= 1.1.12`.
+/// * each version `1.x.y` higher than `1.5.15` of a solana crate depends on other solana crates with req `= 1.x.y`.
+/// * `solana-crate-features` depends on `cc` with the `num_cpus` feature, which doesn't exist in recent versions of `cc`.
+fn backtracking_singletons(c: &mut Criterion, package_count: u32, version_count: u32) {
+    let mut dependency_provider = OfflineDependencyProvider::<u32, Ranges<u32>>::new();
+
+    dependency_provider.add_dependencies(0u32, 0u32, [(1u32, Ranges::full())]);
+    dependency_provider.add_dependencies(1u32, 0u32, []);
+
+    for n in 1..package_count {
+        for v in 1..version_count {
+            dependency_provider.add_dependencies(n, v, [(n + 1, Ranges::singleton(v))]);
+        }
+    }
+
+    c.bench_function("backtracking_singletons", |b| {
+        b.iter(|| {
+            let _ = pubgrub::resolve(&dependency_provider, 0u32, 0u32);
+        })
+    });
+}
+
+/// This benchmark is a simplified reproduction of one of the patterns found in the `solana-*` crates from Cargo:
+/// * `solana-archiver-lib v1.1.12` depends on many layers of other solana crates with req `>= 1.1.12`.
+/// * `solana-archiver-lib v1.1.12` also depends on `ed25519-dalek v1.0.0-pre.3`.
+/// * each version `1.x.y` higher than `1.5.15` of a solana crate depends on other solana crates with req `= 1.x.y`.
+/// * `solana-crate-features >= 1.2.17` depends on `ed25519-dalek v1.0.0-pre.4` or a higher incompatible version.
+fn backtracking_disjoint_versions(c: &mut Criterion, package_count: u32, version_count: u32) {
+    let mut dependency_provider = OfflineDependencyProvider::<u32, Ranges<u32>>::new();
+
+    let root_deps = [(1u32, Ranges::full()), (u32::MAX, Ranges::singleton(0u32))];
+    dependency_provider.add_dependencies(0u32, 0u32, root_deps);
+
+    dependency_provider.add_dependencies(1u32, 0u32, []);
+
+    for n in 1..package_count {
+        for v in 1..version_count {
+            dependency_provider.add_dependencies(n, v, [(n + 1, Ranges::singleton(v))]);
+        }
+    }
+    for v in 1..version_count {
+        dependency_provider.add_dependencies(package_count, v, [(u32::MAX, Ranges::singleton(v))]);
+    }
+
+    for v in 0..version_count {
+        dependency_provider.add_dependencies(u32::MAX, v, []);
+    }
+
+    c.bench_function("backtracking_disjoint_versions", |b| {
+        b.iter(|| {
+            let _ = pubgrub::resolve(&dependency_provider, 0u32, 0u32);
+        })
+    });
+}
+
+/// This benchmark is a simplified reproduction of one of the patterns found in the `solana-*` crates from Cargo:
+/// * `solana-archiver-lib v1.1.12` depends on many layers of other solana crates with req `>= 1.1.12`.
+/// * each version `1.x.y` lower than `1.5.14` of a solana crate depends on other solana crates with req `>= 1.x.y`.
+/// * `solana-crate-features` depends on `cc` with the `num_cpus` feature, which doesn't exist in recent versions of `cc`.
+fn backtracking_ranges(c: &mut Criterion, package_count: u32, version_count: u32) {
+    let mut dependency_provider = OfflineDependencyProvider::<u32, Ranges<u32>>::new();
+
+    dependency_provider.add_dependencies(0u32, 0u32, [(1u32, Ranges::full())]);
+    dependency_provider.add_dependencies(1u32, 0u32, []);
+
+    for n in 1..package_count {
+        for v in 1..version_count {
+            let r = Ranges::higher_than(version_count - v);
+            dependency_provider.add_dependencies(n, v, [(n + 1, r)]);
+        }
+    }
+
+    c.bench_function("backtracking_ranges", |b| {
+        b.iter(|| {
+            let _ = pubgrub::resolve(&dependency_provider, 0u32, 0u32);
+        })
+    });
+}
+
+fn bench_group(c: &mut Criterion) {
+    backtracking_singletons(c, 100, 500);
+    backtracking_disjoint_versions(c, 300, 200);
+    backtracking_ranges(c, 5, 200);
+}
+
+criterion_group!(benches, bench_group);
+criterion_main!(benches);

benches/large_case.rs

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: MPL-2.0
+
 use std::time::Duration;
 
 use criterion::*;

benches/sudoku.rs

@@ -56,8 +56,8 @@ fn from_board(b: &str) -> Vec<(SudokuPackage, Range<Arc<usize>>)> {
             if let Some(val) = val.chars().next().unwrap().to_digit(10) {
                 out.push((
                     SudokuPackage::Cell {
-                        row: (row + 1).try_into().unwrap(),
-                        col: (col + 1).try_into().unwrap(),
+                        row: row + 1,
+                        col: col + 1,
                     },
                     Range::singleton(val as usize),
                 ));

test-examples/large_case_u16_NumberVersion.ron

@@ -5521,4 +5521,4 @@
         18: {},
         19: {},
     },
-}
+}