fix(solc): consistent serde for linked and unlinked bytecode (#948)

ethers-solc/src/artifacts/mod.rs

@@ -1592,6 +1592,7 @@ pub enum BytecodeObject {
     #[serde(deserialize_with = "serde_helpers::deserialize_bytes")]
     Bytecode(Bytes),
     /// Bytecode as hex string that's not fully linked yet and contains library placeholders
+    #[serde(with = "serde_helpers::string_bytes")]
     Unlinked(String),
 }
 
@@ -1612,6 +1613,13 @@ impl BytecodeObject {
             BytecodeObject::Unlinked(_) => None,
         }
     }
+    /// Returns a reference to the underlying `String` if the object is unlinked
+    pub fn as_str(&self) -> Option<&str> {
+        match self {
+            BytecodeObject::Bytecode(_) => None,
+            BytecodeObject::Unlinked(s) => Some(s.as_str()),
+        }
+    }
 
     /// Returns the unlinked `String` if the object is unlinked or empty
     pub fn into_unlinked(self) -> Option<String> {
@@ -1715,10 +1723,10 @@ impl BytecodeObject {
     }
 }
 
-// Returns a not deployable bytecode by default as "0x"
+// Returns a not deployable bytecode by default as empty
 impl Default for BytecodeObject {
     fn default() -> Self {
-        BytecodeObject::Unlinked("0x".to_string())
+        BytecodeObject::Unlinked("".to_string())
     }
 }
 

ethers-solc/src/artifacts/serde_helpers.rs

@@ -77,6 +77,34 @@ pub mod json_string_opt {
     }
 }
 
+/// serde support for string
+pub mod string_bytes {
+    use serde::{Deserialize, Deserializer, Serializer};
+
+    pub fn serialize<S>(value: &String, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        if value.starts_with("0x") {
+            serializer.serialize_str(value.as_str())
+        } else {
+            serializer.serialize_str(&format!("0x{}", value))
+        }
+    }
+
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<String, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let value = String::deserialize(deserializer)?;
+        if let Some(rem) = value.strip_prefix("0x") {
+            Ok(rem.to_string())
+        } else {
+            Ok(value)
+        }
+    }
+}
+
 pub mod display_from_str_opt {
     use serde::{de, Deserialize, Deserializer, Serializer};
     use std::{fmt, str::FromStr};

ethers-solc/tests/project.rs

@@ -496,7 +496,7 @@ fn can_detect_type_error() {
 fn can_compile_single_files() {
     let tmp = TempProject::dapptools().unwrap();
 
-    let foo = tmp
+    let f = tmp
         .add_contract(
             "examples/Foo",
             r#"
@@ -507,7 +507,7 @@ fn can_compile_single_files() {
         )
         .unwrap();
 
-    let compiled = tmp.project().compile_file(foo.clone()).unwrap();
+    let compiled = tmp.project().compile_file(f.clone()).unwrap();
     assert!(!compiled.has_compiler_errors());
     assert!(compiled.find("Foo").is_some());
 
@@ -522,8 +522,43 @@ fn can_compile_single_files() {
         )
         .unwrap();
 
-    let compiled = tmp.project().compile_files(vec![foo, bar]).unwrap();
+    let compiled = tmp.project().compile_files(vec![f, bar]).unwrap();
     assert!(!compiled.has_compiler_errors());
     assert!(compiled.find("Foo").is_some());
     assert!(compiled.find("Bar").is_some());
 }
+
+#[test]
+fn consistent_bytecode() {
+    let tmp = TempProject::dapptools().unwrap();
+
+    tmp.add_source(
+        "LinkTest",
+        r#"
+// SPDX-License-Identifier: MIT
+library LibTest {
+    function foobar(uint256 a) public view returns (uint256) {
+    	return a * 100;
+    }
+}
+contract LinkTest {
+    function foo() public returns (uint256) {
+        return LibTest.foobar(1);
+    }
+}
+"#,
+    )
+    .unwrap();
+
+    let compiled = tmp.compile().unwrap();
+    assert!(!compiled.has_compiler_errors());
+
+    let contract = compiled.find("LinkTest").unwrap();
+    let bytecode = &contract.bytecode.as_ref().unwrap().object;
+    assert!(bytecode.is_unlinked());
+    let s = bytecode.as_str().unwrap();
+    assert!(!s.starts_with("0x"));
+
+    let s = serde_json::to_string(&bytecode).unwrap();
+    assert_eq!(bytecode.clone(), serde_json::from_str(&s).unwrap());
+}