feat: add a proper arbitrary impl for cells

Author: Rexagon

Cargo.toml

@@ -61,6 +61,7 @@ members = ["proc"]
 [dependencies]
 ahash = "0.8.11"
 anyhow = { version = "1.0", optional = true }
+arbitrary = { version = "1", optional = true }
 base64 = { version = "0.22", optional = true }
 bitflags = "2.3"
 blake3 = { version = "1.5", optional = true }
@@ -103,6 +104,7 @@ rand = ["dep:rand"]
 models = ["dep:everscale-crypto", "dep:tl-proto"]
 blake3 = ["dep:blake3"]
 rayon = ["dep:rayon", "blake3?/rayon"]
+arbitrary = ["dep:arbitrary"]
 abi = [
     "dep:anyhow",
     "dep:bytes",

fuzz/Cargo.toml

@@ -13,7 +13,7 @@ libfuzzer-sys = "0.4"
 
 [dependencies.everscale-types]
 path = ".."
-features = ["base64"]
+features = ["base64", "arbitrary"]
 
 # Prevent this from interfering with workspaces
 [workspace]
@@ -31,6 +31,12 @@ path = "fuzz_targets/boc_decode.rs"
 test = false
 doc = false
 
+[[bin]]
+name = "boc_encode"
+path = "fuzz_targets/boc_encode.rs"
+test = false
+doc = false
+
 [[bin]]
 name = "boc_decode_pair"
 path = "fuzz_targets/boc_decode_pair.rs"

fuzz/fuzz_targets/boc_encode.rs

@@ -0,0 +1,8 @@
+#![no_main]
+use libfuzzer_sys::fuzz_target;
+
+use everscale_types::prelude::{Boc, Cell};
+
+fuzz_target!(|cell: Cell| {
+    _ = Boc::encode(cell);
+});