chore(ci): enforce formatting of noir code in CI (#4422)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

We currently format everything in the repository except our noir source
code. If we enforce this internally then we'll uncover issues in the
formatter earlier and provide a good example of what Noir source should
look like.

We then now run `nargo fmt --check` on the stdlib and
`test_programs/execution_success`

## Additional Context



## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

.github/workflows/formatting.yml

@@ -63,3 +63,68 @@ jobs:
 
       - name: Run `yarn lint`
         run: yarn lint
+
+  build-nargo:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 30
+
+    steps:
+      - name: Checkout Noir repo
+        uses: actions/checkout@v4
+
+      - name: Setup toolchain
+        uses: dtolnay/rust-toolchain@1.73.0
+
+      - uses: Swatinem/rust-cache@v2
+        with:
+          key: x86_64-unknown-linux-gnu
+          cache-on-failure: true
+          save-if: ${{ github.event_name != 'merge_group' }}
+
+      - name: Build Nargo
+        run: cargo build --package nargo_cli --release
+
+      - name: Package artifacts
+        run: |
+          mkdir dist
+          cp ./target/release/nargo ./dist/nargo
+          7z a -ttar -so -an ./dist/* | 7z a -si ./nargo-x86_64-unknown-linux-gnu.tar.gz
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: nargo
+          path: ./dist/*
+          retention-days: 3
+
+  nargo_fmt:
+    needs: [build-nargo]
+    name: Nargo fmt
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Download nargo binary
+        uses: actions/download-artifact@v4
+        with:
+          name: nargo
+          path: ./nargo
+
+      - name: Set nargo on PATH
+        run: |
+          nargo_binary="${{ github.workspace }}/nargo/nargo"
+          chmod +x $nargo_binary
+          echo "$(dirname $nargo_binary)" >> $GITHUB_PATH
+          export PATH="$PATH:$(dirname $nargo_binary)"
+          nargo -V
+
+      - name: Format stdlib
+        working-directory: ./noir_stdlib
+        run: nargo fmt --check
+
+      - name: Format test suite
+        working-directory: ./test_programs
+        run: ./format.sh check

noir_stdlib/src/array.nr

@@ -17,42 +17,41 @@ impl<T, N> [T; N] {
         for i in 0..N {
             let pos = find_index(sorted_index, i);
             assert(sorted_index[pos] == i);
-         }
+        }
         // Sort the array using the indexes
-         for i in 0..N {
+        for i in 0..N {
             result[i] = self[sorted_index[i]];
-         }
+        }
         // Ensure the array is sorted
-        for i in 0..N-1 {
-            assert(ordering(result[i], result[i+1]));
+        for i in 0..N - 1 {
+            assert(ordering(result[i], result[i + 1]));
         }
 
         result
     }
 
     /// Returns the index of the elements in the array that would sort it, using the provided custom sorting function.
     unconstrained fn get_sorting_index<Env>(self, ordering: fn[Env](T, T) -> bool) -> [u64; N] {
-        let mut result = [0;N];
+        let mut result = [0; N];
         let mut a = self;
         for i in 0..N {
             result[i] = i;
         }
-        for i in 1 .. N {
+        for i in 1..N {
             for j in 0..i {
                 if ordering(a[i], a[j]) {
                     let old_a_j = a[j];
                     a[j] = a[i];
                     a[i] = old_a_j;
                     let old_j = result[j];
                     result[j] = result[i];
-                    result[i] = old_j; 
+                    result[i] = old_j;
                 }
             }
         }
         result
     }
 
-
     // Converts an array into a slice.
     pub fn as_slice(self) -> [T] {
         let mut slice = [];
@@ -68,7 +67,7 @@ impl<T, N> [T; N] {
         let first_elem = f(self[0]);
         let mut ret = [first_elem; N];
 
-        for i in 1 .. self.len() {
+        for i in 1..self.len() {
             ret[i] = f(self[i]);
         }
 
@@ -90,7 +89,7 @@ impl<T, N> [T; N] {
     // element of the given array as its starting accumulator value.
     pub fn reduce<Env>(self, f: fn[Env](T, T) -> T) -> T {
         let mut accumulator = self[0];
-        for i in 1 .. self.len() {
+        for i in 1..self.len() {
             accumulator = f(accumulator, self[i]);
         }
         accumulator
@@ -122,7 +121,7 @@ unconstrained fn find_index<N>(a: [u64; N], find: u64) -> u64 {
     for i in 0..a.len() {
         if a[i] == find {
             result = i;
-        }     
+        }
     }
     result
 }

noir_stdlib/src/bigint.nr

@@ -1,5 +1,4 @@
-use crate::ops::{Add, Sub, Mul, Div, Rem,};
-
+use crate::ops::{Add, Sub, Mul, Div, Rem};
 
 global bn254_fq = [0x47, 0xFD, 0x7C, 0xD8, 0x16, 0x8C, 0x20, 0x3C, 0x8d, 0xca, 0x71, 0x68, 0x91, 0x6a, 0x81, 0x97,
                    0x5d, 0x58, 0x81, 0x81, 0xb6, 0x45, 0x50, 0xb8, 0x29, 0xa0, 0x31, 0xe1, 0x72, 0x4e, 0x64, 0x30];
@@ -13,7 +12,6 @@ global secpr1_fq = [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
                     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF];
 global secpr1_fr = [0x51, 0x25, 0x63, 0xFC, 0xC2, 0xCA, 0xB9, 0xF3, 0x84, 0x9E, 0x17, 0xA7, 0xAD, 0xFA, 0xE6, 0xBC,
                     0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00,0xFF, 0xFF, 0xFF, 0xFF];
-
 
 struct BigInt {
     pointer: u32,
@@ -22,17 +20,13 @@ struct BigInt {
 
 impl BigInt {
     #[builtin(bigint_add)]
-    fn bigint_add(self, other: BigInt) -> BigInt {
-    }
+    fn bigint_add(self, other: BigInt) -> BigInt {}
     #[builtin(bigint_sub)]
-    fn bigint_sub(self, other: BigInt) -> BigInt {
-    }
+    fn bigint_sub(self, other: BigInt) -> BigInt {}
     #[builtin(bigint_mul)]
-    fn bigint_mul(self, other: BigInt) -> BigInt {
-    }
+    fn bigint_mul(self, other: BigInt) -> BigInt {}
     #[builtin(bigint_div)]
-    fn bigint_div(self, other: BigInt) -> BigInt {
-    }
+    fn bigint_div(self, other: BigInt) -> BigInt {}
     #[builtin(bigint_from_le_bytes)]
     fn from_le_bytes(bytes: [u8], modulus: [u8]) -> BigInt {}
     #[builtin(bigint_to_le_bytes)]

noir_stdlib/src/collections/bounded_vec.nr

@@ -29,7 +29,7 @@ impl<T, MaxLen> BoundedVec<T, MaxLen> {
         self.len
     }
 
-    pub fn max_len(_self: BoundedVec<T, MaxLen>) -> u64{
+    pub fn max_len(_self: BoundedVec<T, MaxLen>) -> u64 {
         MaxLen
     }
 

noir_stdlib/src/collections/vec.nr

@@ -19,20 +19,20 @@ impl<T> Vec<T> {
     /// points beyond the end of the vector.
     pub fn get(self, index: u64) -> T {
         self.slice[index]
-     }
+    }
 
     /// Push a new element to the end of the vector, returning a
     /// new vector with a length one greater than the
     /// original unmodified vector.
-    pub fn push(&mut self, elem: T) { 
+    pub fn push(&mut self, elem: T) {
         self.slice = self.slice.push_back(elem);
     }
 
     /// Pop an element from the end of the given vector, returning
     /// a new vector with a length of one less than the given vector,
     /// as well as the popped element.
     /// Panics if the given vector's length is zero.
-    pub fn pop(&mut self) -> T { 
+    pub fn pop(&mut self) -> T {
         let (popped_slice, last_elem) = self.slice.pop_back();
         self.slice = popped_slice;
         last_elem
@@ -42,7 +42,7 @@ impl<T> Vec<T> {
     /// after it to the right
     pub fn insert(&mut self, index: u64, elem: T) {
         self.slice = self.slice.insert(index, elem);
-    } 
+    }
 
     /// Remove an element at a specified index, shifting all elements
     /// after it to the left, returning the removed element