chore: improve unlinked bytecode deserde error

crates/json-abi/src/abi.rs

@@ -529,20 +529,39 @@ impl<'de> Visitor<'de> for ContractObjectVisitor {
         f.write_str("an ABI sequence or contract object")
     }
 
+    #[inline]
+    fn visit_seq<A: SeqAccess<'de>>(self, seq: A) -> Result<Self::Value, A::Error> {
+        JsonAbiVisitor.visit_seq(seq).map(|abi| ContractObject {
+            abi: Some(abi),
+            bytecode: None,
+            deployed_bytecode: None,
+        })
+    }
+
     fn visit_map<A: MapAccess<'de>>(self, mut map: A) -> Result<Self::Value, A::Error> {
         #[derive(Deserialize)]
         #[serde(untagged)]
         enum Bytecode {
             Bytes(Bytes),
             Object { object: Bytes },
+            Unlinked(String),
+            UnlinkedObject { object: String },
         }
 
         impl Bytecode {
-            #[allow(clippy::missing_const_for_fn)]
-            #[inline(always)]
-            fn bytes(self) -> Bytes {
-                let (Self::Object { object: bytes } | Self::Bytes(bytes)) = self;
-                bytes
+            fn ensure_bytes<E: serde::de::Error>(self) -> Result<Bytes, E> {
+                match self {
+                    Bytecode::Bytes(bytes) | Bytecode::Object { object: bytes } => Ok(bytes),
+                    Bytecode::Unlinked(unlinked)
+                    | Bytecode::UnlinkedObject { object: unlinked } => {
+                        if let Some((_, unlinked)) = unlinked.split_once("__$") {
+                            if let Some((addr, _)) = unlinked.split_once("$__") {
+                                return Err(E::custom(format!("expected bytecode, found unlinked bytecode with placeholder: {addr}")));
+                            }
+                        }
+                        Err(E::custom("invalid contract bytecode"))
+                    }
+                }
             }
         }
 
@@ -564,18 +583,18 @@ impl<'de> Visitor<'de> for ContractObjectVisitor {
                 "evm" => {
                     let evm = map.next_value::<EvmObj>()?;
                     if let Some(bytes) = evm.bytecode {
-                        set_if_none!(@serde bytecode, bytes.bytes());
+                        set_if_none!(@serde bytecode, bytes.ensure_bytes()?);
                     }
                     if let Some(bytes) = evm.deployed_bytecode {
-                        set_if_none!(@serde deployed_bytecode, bytes.bytes());
+                        set_if_none!(@serde deployed_bytecode, bytes.ensure_bytes()?);
                     }
                 }
                 "bytecode" | "bin" => {
-                    set_if_none!(@serde bytecode, map.next_value::<Bytecode>()?.bytes());
+                    set_if_none!(@serde bytecode, map.next_value::<Bytecode>()?.ensure_bytes()?);
                 }
                 "deployedBytecode" | "deployedbytecode" | "deployed_bytecode" | "runtimeBin"
                 | "runtimebin" | "runtime " => {
-                    set_if_none!(@serde deployed_bytecode, map.next_value::<Bytecode>()?.bytes());
+                    set_if_none!(@serde deployed_bytecode, map.next_value::<Bytecode>()?.ensure_bytes()?);
                 }
                 _ => {
                     map.next_value::<serde::de::IgnoredAny>()?;
@@ -585,13 +604,4 @@ impl<'de> Visitor<'de> for ContractObjectVisitor {
 
         Ok(ContractObject { abi, bytecode, deployed_bytecode })
     }
-
-    #[inline]
-    fn visit_seq<A: SeqAccess<'de>>(self, seq: A) -> Result<Self::Value, A::Error> {
-        JsonAbiVisitor.visit_seq(seq).map(|abi| ContractObject {
-            abi: Some(abi),
-            bytecode: None,
-            deployed_bytecode: None,
-        })
-    }
 }

crates/json-abi/tests/abi.rs

@@ -1,4 +1,4 @@
-use alloy_json_abi::{AbiItem, EventParam, JsonAbi, Param};
+use alloy_json_abi::{AbiItem, ContractObject, EventParam, JsonAbi, Param};
 use pretty_assertions::assert_eq;
 use std::{
     collections::HashMap,
@@ -10,6 +10,8 @@ use std::{
 
 const JSON_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/tests/abi");
 
+const TESTDATA_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/tests/testdata");
+
 static UPDATED: AtomicBool = AtomicBool::new(false);
 
 #[test]
@@ -283,3 +285,15 @@ fn get_solc_version() -> Option<(u16, u16, u16)> {
     let patch = iter.next().unwrap();
     Some((major, minor, patch))
 }
+
+// <https://github.com/foundry-rs/foundry/issues/6815>
+#[test]
+#[cfg_attr(miri, ignore = "no fs")]
+#[cfg(all(feature = "std", feature = "serde_json"))]
+fn parse_unlinked_contract() {
+    // unlinked placeholder __$7233c33f2e1e35848c685b0eb24649959e$__
+    let content = fs::read_to_string(Path::new(TESTDATA_PATH).join("UnlinkedNouns.json")).unwrap();
+    let res = serde_json::from_str::<ContractObject>(&content);
+    let err = res.unwrap_err();
+    assert!(err.to_string().contains("expected bytecode, found unlinked bytecode with placeholder: 7233c33f2e1e35848c685b0eb24649959e"));
+}