Add justfile and CI

.github/workflows/rust.yml

@@ -0,0 +1,40 @@
+# A few guiding principles.
+#
+# * Always use actions-rust-lang/setup-rust-toolchain for its built-in caching.
+# * Complexity lives in the justfile, this runner is as light as possible.
+
+name: CI
+
+# Run on direct commits to master, including merges, and any pull requests against master.
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  # Quick canary of code as well as potential issues with upcoming toolchains.
+  check:
+    strategy:
+      matrix:
+        toolchain: [stable, beta, nightly]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v3
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: ${{ matrix.toolchain }}
+          components: clippy,rustfmt
+      - run: just check
+  # Build and test the code across platforms.
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v3
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+      - name: "Run test suite"
+        run: just test

.github/workflows/weekly-check.yml

@@ -0,0 +1,25 @@
+# Attempt to detect any upcoming breaking changes if CI hasn't been run in awhile.
+name: Weekly Check
+
+on:
+  # Allows manual triggering.
+  workflow_dispatch:
+  schedule:
+   # Run at midnight on Sundays.
+   - cron: "0 0 * * 0"
+
+jobs:
+  # Quick canary of code as well as potential issues with upcoming toolchains.
+  check:
+    strategy:
+      matrix:
+        toolchain: [stable, beta, nightly]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: extractions/setup-just@v3
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: ${{ matrix.toolchain }}
+          components: clippy,rustfmt
+      - run: just check

.gitignore

@@ -1 +1,2 @@
 /target
+!justfile

curve/src/lib.rs

@@ -41,7 +41,8 @@ pub struct Secp256k1Curve;
 
 impl Secp256k1Curve {
     pub const A: FieldElement<Secp256k1FieldOrder> = FieldElement::ZERO;
-    pub const B: FieldElement<Secp256k1FieldOrder> = FieldElement::from_limbs_unchecked([7, 0, 0, 0]);
+    pub const B: FieldElement<Secp256k1FieldOrder> =
+        FieldElement::from_limbs_unchecked([7, 0, 0, 0]);
 
     pub const GENERATOR: Point<Secp256k1FieldOrder> = Point::from_affine(
         FieldElement::from_limbs_unchecked([
@@ -151,7 +152,11 @@ impl<F: FieldOrder> Point<F> {
         let y3 = m * (s - t) - eight_yyyy;
         let y_plus_z = self.y + self.z;
         let z3 = y_plus_z * y_plus_z - yy - zz;
-        Self { x: x3, y: y3, z: z3 }
+        Self {
+            x: x3,
+            y: y3,
+            z: z3,
+        }
     }
 
     fn add(&self, other: &Self, a: FieldElement<F>) -> Self {
@@ -188,7 +193,11 @@ impl<F: FieldOrder> Point<F> {
         let y3 = r * (v - x3) - two_s1_j;
         let z1_plus_z2 = self.z + other.z;
         let z3 = (z1_plus_z2 * z1_plus_z2 - z1z1 - z2z2) * h;
-        Self { x: x3, y: y3, z: z3 }
+        Self {
+            x: x3,
+            y: y3,
+            z: z3,
+        }
     }
 
     fn mul<G: FieldOrder>(&self, scalar: Scalar<G>, a: FieldElement<F>) -> Self {
@@ -389,11 +398,7 @@ mod tests {
 
     #[test]
     fn mul_by_zero_is_infinity() {
-        assert!(
-            CURVE
-                .multiply(Sc::from_u128(0), generator())
-                .is_infinity()
-        );
+        assert!(CURVE.multiply(Sc::from_u128(0), generator()).is_infinity());
     }
 
     #[test]

field/src/lib.rs

@@ -3,9 +3,7 @@ use core::hash::Hash;
 use core::marker::PhantomData;
 use core::ops::{Add, AddAssign, Mul, MulAssign, Sub, SubAssign};
 
-pub trait Limbs:
-    Copy + fmt::Debug + PartialEq + Eq + Hash + AsRef<[u64]> + AsMut<[u64]>
-{
+pub trait Limbs: Copy + fmt::Debug + PartialEq + Eq + Hash + AsRef<[u64]> + AsMut<[u64]> {
     const ZERO: Self;
     const ONE: Self;
     const TWO: Self;
@@ -317,7 +315,11 @@ fn wide_mul<L: Limbs>(a: &L, b: &L) -> (L, L) {
             let mut carry = 0u64;
             for (j, &bj) in b_slice.iter().enumerate() {
                 let idx = i + j;
-                let cell = if idx < n { lo_slice[idx] } else { hi_slice[idx - n] };
+                let cell = if idx < n {
+                    lo_slice[idx]
+                } else {
+                    hi_slice[idx - n]
+                };
                 let (product, new_carry) = a_slice[i].carrying_mul_add(bj, cell, carry);
                 if idx < n {
                     lo_slice[idx] = product;

isogeny/src/lib.rs

@@ -0,0 +1 @@
+

justfile

@@ -0,0 +1,21 @@
+check:
+  cargo fmt -- --check
+  cargo clippy --all-targets -- -D warnings
+  cargo check --all-features
+
+# Run a test suite: unit, msrv, min-versions
+test suite="workspace":
+  just _test-{{suite}}
+
+_test-workspace:
+  cargo test --workspace
+
+# Delete unused files or branches: data, lockfile, branches
+delete item="branches":
+  just _delete-{{item}}
+
+_delete-lockfile:
+  rm -f Cargo.lock
+
+_delete-branches:
+  git branch --merged | grep -v \* | xargs git branch -d