fuzz: add txs_prepare_proposal

Makefile

@@ -276,6 +276,9 @@ bench:
 fuzz-txs-mempool:
 	$(cargo) +$(nightly) fuzz run txs_mempool --dev
 
+fuzz-txs-prepare-proposal:
+	$(cargo) +$(nightly) fuzz run txs_prepare_proposal --dev
+
 build-doc:
 	$(cargo) doc --no-deps
 

fuzz/Cargo.toml

@@ -16,6 +16,15 @@ lazy_static.workspace = true
 libfuzzer-sys = "0.4"
 
 [[bin]]
+name = "txs_mempool"
+path = "fuzz_targets/txs_mempool.rs"
+test = false
+doc = false
+bench = false
+
+[[bin]]
+name = "txs_prepare_proposal"
+path = "fuzz_targets/txs_prepare_proposal.rs"
 test = false
 doc = false
 bench = false

fuzz/fuzz_targets/txs_prepare_proposal.rs

@@ -0,0 +1,33 @@
+#![no_main]
+
+use lazy_static::lazy_static;
+use libfuzzer_sys::fuzz_target;
+use namada_node::facade::tendermint_proto::v0_37::abci::RequestPrepareProposal;
+use namada_node::shell;
+use namada_node::shell::test_utils::TestShell;
+use namada_node::shims::abcipp_shim_types::shim::TxBytes;
+use namada_tx::Tx;
+
+lazy_static! {
+    static ref SHELL: TestShell = {
+        let (shell, _recv, _, _) = shell::test_utils::setup();
+        shell
+    };
+}
+
+fuzz_target!(|txs: Vec<Tx>| {
+    let mut txs_bytes: Vec<TxBytes> = Vec::with_capacity(txs.len());
+    for tx in txs {
+        if let Ok(tx_bytes) = tx.try_to_bytes() {
+            txs_bytes.push(tx_bytes.into());
+        } else {
+            return;
+        }
+    }
+
+    let req = RequestPrepareProposal {
+        txs: txs_bytes,
+        ..Default::default()
+    };
+    SHELL.prepare_proposal(req);
+});