From 02798612a7b1b44687b70cf98c90fabbbabea5de Mon Sep 17 00:00:00 2001
From: nymius <155548262+nymius@users.noreply.github.com>
Date: Wed, 2 Jul 2025 17:20:17 -0300
Subject: [PATCH 1/2] ci: add incremental-mutants job to execute cargo mutants
 against PR diff

---
 .cargo/mutants.toml             |  1 +
 .github/workflows/mutations.yml | 42 +++++++++++++++++++++++++++++++++
 .gitignore                      |  3 +++
 Cargo.toml                      |  5 ++++
 4 files changed, 51 insertions(+)
 create mode 100644 .cargo/mutants.toml
 create mode 100644 .github/workflows/mutations.yml

diff --git a/.cargo/mutants.toml b/.cargo/mutants.toml
new file mode 100644
index 0000000..3ed309f
--- /dev/null
+++ b/.cargo/mutants.toml
@@ -0,0 +1 @@
+profile = "mutants"
diff --git a/.github/workflows/mutations.yml b/.github/workflows/mutations.yml
new file mode 100644
index 0000000..e1a59d8
--- /dev/null
+++ b/.github/workflows/mutations.yml
@@ -0,0 +1,42 @@
+name: Test mutants
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  incremental-mutants:
+    name: Incremental mutants test
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Relative diff
+        run: |
+          git branch -av
+          git diff origin/${{ github.base_ref }}.. | tee git.diff
+      - name: Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Install Rust toolchain
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-mutants
+      - name: Mutants
+        run: |
+          cargo mutants --no-shuffle -vV --exclude "example-crates/**" --in-diff git.diff -- --all-targets
+      - name: Archive mutants.out
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: mutants-incremental.out
+          path: mutants.out
diff --git a/.gitignore b/.gitignore
index 5348570..f8ac0d2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,6 @@ Cargo.lock
 
 # Ignore media (should go into media branch)
 *.gif
+
+# Ignore cargo-mutants generated output
+/mutants.out*
diff --git a/Cargo.toml b/Cargo.toml
index 076aadb..6832a68 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,3 +14,8 @@ print_stderr = "deny"
 
 [workspace.lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(coverage,coverage_nightly)'] }
+
+[profile.mutants]
+inherits = "test"
+debug = "none"
+opt-level = 3

From bc56ce7ddfa1dc07981c280335a8e6ededb04e01 Mon Sep 17 00:00:00 2001
From: nymius <155548262+nymius@users.noreply.github.com>
Date: Wed, 2 Jul 2025 15:45:06 -0300
Subject: [PATCH 2/2] test: add code harness to fuzz with AFL, libFuzz and
 honggfuzz

---
 .github/workflows/coverage.yml |  2 +-
 Cargo.toml                     |  5 +++-
 fuzz/.gitignore                |  7 ++++++
 fuzz/Cargo.toml                | 35 ++++++++++++++++++++++++++
 fuzz/seeds/seed.txt            |  1 +
 fuzz/src/bin/sp_code_target.rs | 45 ++++++++++++++++++++++++++++++++++
 fuzz/src/lib.rs                | 10 ++++++++
 fuzz/src/sp_code.rs            | 20 +++++++++++++++
 justfile                       |  6 ++---
 9 files changed, 126 insertions(+), 5 deletions(-)
 create mode 100644 fuzz/.gitignore
 create mode 100644 fuzz/Cargo.toml
 create mode 100644 fuzz/seeds/seed.txt
 create mode 100644 fuzz/src/bin/sp_code_target.rs
 create mode 100644 fuzz/src/lib.rs
 create mode 100644 fuzz/src/sp_code.rs

diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 75b90b4..6a50429 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -30,7 +30,7 @@ jobs:
       - name: Make coverage directory
         run: mkdir coverage
       - name: Test and report coverage
-        run: cargo +nightly llvm-cov -q --doctests --branch --all --ignore-filename-regex "example-crates/*" --all-features --lcov --output-path ./coverage/lcov.info
+        run: cargo +nightly llvm-cov -q --doctests --branch --all --exclude sp_fuzz --ignore-filename-regex "example-crates/*" --all-features --lcov --output-path ./coverage/lcov.info
       - name: Generate HTML coverage report
         run: genhtml -o coverage-report.html --ignore-errors unmapped ./coverage/lcov.info
       - name: Coveralls upload
diff --git a/Cargo.toml b/Cargo.toml
index 6832a68..a1f06db 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,10 @@
 resolver = "2"
 members = [
     "silentpayments",
-    "example-crates/example_silentpayments", "dleq", "indexer",
+    "example-crates/example_silentpayments", "dleq", "indexer", "fuzz",
+]
+default-members = [
+    "silentpayments", "dleq", "indexer",
 ]
 
 [workspace.package]
diff --git a/fuzz/.gitignore b/fuzz/.gitignore
new file mode 100644
index 0000000..c75a8ff
--- /dev/null
+++ b/fuzz/.gitignore
@@ -0,0 +1,7 @@
+hfuzz_target
+hfuzz_workspace
+target
+corpus
+artifacts
+# AFL
+out
diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
new file mode 100644
index 0000000..3c98875
--- /dev/null
+++ b/fuzz/Cargo.toml
@@ -0,0 +1,35 @@
+[package]
+name = "sp_fuzz"
+version = "0.1.0"
+edition = "2024"
+publish = false
+authors.workspace = true
+
+[features]
+afl_fuzz = ["afl"]
+honggfuzz_fuzz = ["honggfuzz"]
+libfuzzer_fuzz = ["libfuzzer-sys"]
+stdin_fuzz = []
+
+[dependencies]
+bdk_sp = { version = "0.1.0", path = "../silentpayments" }
+afl = { version = "0.12", optional = true }
+honggfuzz = { version = "0.5", optional = true, default-features = false }
+libfuzzer-sys = { version = "0.4", optional = true }
+
+[lib]
+name = "sp_fuzz"
+path = "src/lib.rs"
+
+[[bin]]
+name = "sp_encoding"
+path = "src/bin/sp_code_target.rs"
+
+[lints.rust.unexpected_cfgs]
+level = "forbid"
+check-cfg = [
+    "cfg(fuzzing)",
+    "cfg(secp256k1_fuzz)",
+    "cfg(hashes_fuzz)",
+    "cfg(taproot)",
+]
diff --git a/fuzz/seeds/seed.txt b/fuzz/seeds/seed.txt
new file mode 100644
index 0000000..834bcde
--- /dev/null
+++ b/fuzz/seeds/seed.txt
@@ -0,0 +1 @@
+Hello, AFL!
diff --git a/fuzz/src/bin/sp_code_target.rs b/fuzz/src/bin/sp_code_target.rs
new file mode 100644
index 0000000..93c236a
--- /dev/null
+++ b/fuzz/src/bin/sp_code_target.rs
@@ -0,0 +1,45 @@
+#![cfg_attr(feature = "libfuzzer_fuzz", no_main)]
+
+use bdk_sp::encoding::SilentPaymentCode;
+use core::convert::TryFrom;
+
+use sp_fuzz::sp_code::sp_code_parse_run;
+
+#[cfg(feature = "afl")]
+#[macro_use]
+extern crate afl;
+#[cfg(feature = "afl")]
+fn main() {
+    fuzz!(|data| {
+        sp_code_parse_run(data.as_ptr(), data.len());
+    });
+}
+
+#[cfg(feature = "honggfuzz")]
+#[macro_use]
+extern crate honggfuzz;
+#[cfg(feature = "honggfuzz")]
+fn main() {
+    loop {
+        fuzz!(|data| {
+            sp_code_parse_run(data.as_ptr(), data.len());
+        });
+    }
+}
+
+#[cfg(feature = "libfuzzer_fuzz")]
+#[macro_use]
+extern crate libfuzzer_sys;
+#[cfg(feature = "libfuzzer_fuzz")]
+fuzz_target!(|data: &[u8]| {
+    sp_code_parse_run(data.as_ptr(), data.len());
+});
+
+#[cfg(feature = "stdin_fuzz")]
+fn main() {
+    use std::io::Read;
+
+    let mut data = Vec::with_capacity(1023);
+    std::io::stdin().read_to_end(&mut data).unwrap();
+    sp_code_parse_run(data.as_ptr(), data.len());
+}
diff --git a/fuzz/src/lib.rs b/fuzz/src/lib.rs
new file mode 100644
index 0000000..5762ddc
--- /dev/null
+++ b/fuzz/src/lib.rs
@@ -0,0 +1,10 @@
+#[cfg(not(fuzzing))]
+compile_error!("Fuzz targets need cfg=fuzzing");
+
+#[cfg(not(hashes_fuzz))]
+compile_error!("Fuzz targets need cfg=hashes_fuzz");
+
+#[cfg(not(secp256k1_fuzz))]
+compile_error!("Fuzz targets need cfg=secp256k1_fuzz");
+
+pub mod sp_code;
diff --git a/fuzz/src/sp_code.rs b/fuzz/src/sp_code.rs
new file mode 100644
index 0000000..bf36a7e
--- /dev/null
+++ b/fuzz/src/sp_code.rs
@@ -0,0 +1,20 @@
+use bdk_sp::encoding::SilentPaymentCode;
+use core::convert::TryFrom;
+
+#[inline]
+pub fn do_test(data: &[u8]) {
+    if let Ok(received_sp_code) = std::str::from_utf8(data) {
+        if let Ok(sp_code) = SilentPaymentCode::try_from(received_sp_code) {
+            let produced_sp_code = sp_code.to_string();
+            assert_eq!(received_sp_code, produced_sp_code);
+        }
+    }
+}
+pub fn sp_code_parse_test(data: &[u8]) {
+    do_test(data);
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn sp_code_parse_run(data: *const u8, datalen: usize) {
+    do_test(unsafe { std::slice::from_raw_parts(data, datalen) });
+}
diff --git a/justfile b/justfile
index e568ffd..973ab7d 100644
--- a/justfile
+++ b/justfile
@@ -10,12 +10,12 @@ default:
 
 [doc("Build the project")]
 build:
-  cargo build
+  cargo build --exclude sp_fuzz
 
 [doc("Check code: formatting, compilation, linting, and commit signature")]
 check:
   cargo +nightly fmt --all -- --check
-  cargo check --workspace --exclude 'example_*' --all-features
+  cargo check --workspace --exclude sp_fuzz --exclude 'example_*' --all-features
   cargo clippy --all-features --all-targets -- -D warnings
   @[ "$(git log --pretty='format:%G?' -1 HEAD)" = "N" ] && \
       echo "\n⚠️  Unsigned commit: BDK requires that commits be signed." || \
@@ -27,7 +27,7 @@ fmt:
 
 [doc("Run all tests on the workspace with all features")]
 test:
-  cargo test --workspace --exclude 'example_*' --all-features
+  cargo test --workspace --exclude sp_fuzz --exclude 'example_*' --all-features
 
 [doc("Run pre-push suite: format, check, and test")]
 pre-push: fmt check test