ci: add weekly sharded cargo-mutants (22119) + in-diff PR advisory (follows #593)

.github/workflows/mutants.yml

@@ -0,0 +1,60 @@
+name: mutants
+on:
+  schedule:
+    - cron: "0 3 * * 0"
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - "crates/**"
+      - ".github/workflows/mutants.yml"
+
+permissions:
+  contents: read
+
+jobs:
+  mutants-pr:
+    if: github.event_name == 'pull_request'
+    concurrency:
+      group: mutants-pr-${{ github.ref }}
+      cancel-in-progress: true
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        with:
+          persist-credentials: false
+          submodules: false
+          fetch-depth: 0
+      - uses: dtolnay/rust-toolchain@a5f673d0ba8626c3977bb416a1612774bc82181b
+      - uses: taiki-e/install-action@9534c84618278caac52cb373bb164ed464dbd8af
+        with:
+          tool: cargo-mutants@27.1.0
+      - run: git diff origin/${{ github.base_ref }}.. --unified=0 > git.diff
+      - run: cargo mutants --workspace --in-diff git.diff -j 2
+        continue-on-error: true
+
+  mutants-weekly:
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-latest
+    timeout-minutes: 360
+    strategy:
+      fail-fast: false
+      matrix:
+        shard: [0, 1, 2, 3, 4, 5, 6, 7]
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1
+        with:
+          persist-credentials: false
+          submodules: false
+      - uses: dtolnay/rust-toolchain@a5f673d0ba8626c3977bb416a1612774bc82181b
+      - uses: taiki-e/install-action@9534c84618278caac52cb373bb164ed464dbd8af
+        with:
+          tool: cargo-mutants@27.1.0
+      - run: cargo mutants --workspace --shard ${{ matrix.shard }}/8 -j 2
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a
+        if: always()
+        with:
+          name: mutants-${{ matrix.shard }}
+          path: mutants.out

crates/rbitcoin-primitives/src/script_sigops.rs

@@ -58,6 +58,22 @@ pub fn script_sigop_count(script: &[u8], accurate: bool) -> u64 {
 
 #[cfg(test)]
 mod tests {
+
+    #[test]
+    fn sigop_count_covers_pushdata_and_truncation() {
+        // 21 -= : [4c,2,ac] original 0, mutant i-=1 => 1
+        assert_eq!(script_sigop_count(&[0x4c, 2, 0xac], true), 0);
+        // 21 *= : [4c,1,ac] original 0, mutant i*=1 => 1
+        assert_eq!(script_sigop_count(&[0x4c, 1, 0xac], true), 0);
+        // 28 *= : [4d,1,0,ac] original 0, mutant i*=2 => 1
+        assert_eq!(script_sigop_count(&[0x4d, 1, 0, 0xac], true), 0);
+        // 41 > vs >= vs == : truncated must be 0
+        assert_eq!(script_sigop_count(&[0x02, 0x00], true), 0);
+        assert_eq!(script_sigop_count(&[0x4c, 2, 0xac, 0xac], true), 0);
+        // extra long killer for 21 -= if guard changes
+        assert_eq!(script_sigop_count(&[0x4c, 2, 0xac, 0xac, 0xac], true), 1); // PUSHDATA1 2 [ac,ac] + ac => 1
+    }
+
     use super::*;
 
     #[test]

docs/mutants/missed.md

@@ -0,0 +1,11 @@
+# Mutants Baseline
+
+> Generated: 2026-09-20 16:14 ET · Runner: M4 mini · consensus 2026-09-19 night → 2026-09-20 morning (9h, 2518 tested) · primitives 2026-09-20 ~15:00 ET (16m, 292 tested)
+
+| Crate | Tested | Missed | Timeout | Details |
+| :--- | ---: | ---: | ---: | :--- |
+| `rbitcoin-primitives` | 292 | 4 | 8 | [./rbitcoin-primitives.md](./rbitcoin-primitives.md) |
+| `rbitcoin-consensus` | 2518 | 304 | 38 | [./rbitcoin-consensus.md](./rbitcoin-consensus.md) |
+
+### Top files - consensus
+- `block/mod.rs` 65 · `script/interpreter.rs` 57 · `silent_payments.rs` 50 · `confirm_run/write.rs` 23 · `confirm_run/pin.rs` 22