feat(cast): decode-error with sig, local cache and openchain api (foundry-rs#9428)

* feat(cast): Add custom error decoding support

* Review changes

* Changes after review: decode with Openchain too, add test

* Review changes: nit, handle incomplete selectors

Author: grandizzy

crates/cast/bin/args.rs

@@ -539,6 +539,16 @@ pub enum CastSubcommand {
         data: String,
     },
 
+    /// Decode custom error data.
+    #[command(visible_aliases = &["error-decode", "--error-decode", "erd"])]
+    DecodeError {
+        /// The error signature. If none provided then tries to decode from local cache or `https://api.openchain.xyz`.
+        #[arg(long, visible_alias = "error-sig")]
+        sig: Option<String>,
+        /// The error data to decode.
+        data: String,
+    },
+
     /// Decode ABI-encoded input or output data.
     ///
     /// Defaults to decoding output data. To decode input data pass --input.

crates/cast/bin/main.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate tracing;
 
-use alloy_dyn_abi::{DynSolValue, EventExt};
+use alloy_dyn_abi::{DynSolValue, ErrorExt, EventExt};
 use alloy_primitives::{eip191_hash_message, hex, keccak256, Address, B256};
 use alloy_provider::Provider;
 use alloy_rpc_types::{BlockId, BlockNumberOrTag::Latest};
@@ -11,7 +11,7 @@ use clap_complete::generate;
 use eyre::Result;
 use foundry_cli::{handler, utils};
 use foundry_common::{
-    abi::get_event,
+    abi::{get_error, get_event},
     ens::{namehash, ProviderEnsExt},
     fmt::{format_tokens, format_tokens_raw, format_uint_exp},
     fs,
@@ -30,6 +30,7 @@ pub mod cmd;
 pub mod tx;
 
 use args::{Cast as CastArgs, CastSubcommand, ToBaseArgs};
+use cast::traces::identifier::SignaturesIdentifier;
 
 #[macro_use]
 extern crate foundry_common;
@@ -216,6 +217,28 @@ async fn main_args(args: CastArgs) -> Result<()> {
             let decoded_event = event.decode_log_parts(None, &hex::decode(data)?, false)?;
             print_tokens(&decoded_event.body);
         }
+        CastSubcommand::DecodeError { sig, data } => {
+            let error = if let Some(err_sig) = sig {
+                get_error(err_sig.as_str())?
+            } else {
+                let data = data.strip_prefix("0x").unwrap_or(data.as_str());
+                let selector = data.get(..8).unwrap_or_default();
+                let identified_error =
+                    SignaturesIdentifier::new(Config::foundry_cache_dir(), false)?
+                        .write()
+                        .await
+                        .identify_error(&hex::decode(selector)?)
+                        .await;
+                if let Some(error) = identified_error {
+                    let _ = sh_println!("{}", error.signature());
+                    error
+                } else {
+                    eyre::bail!("No matching error signature found for selector `{selector}`")
+                }
+            };
+            let decoded_error = error.decode_error(&hex::decode(data)?)?;
+            print_tokens(&decoded_error.body);
+        }
         CastSubcommand::Interface(cmd) => cmd.run().await?,
         CastSubcommand::CreationCode(cmd) => cmd.run().await?,
         CastSubcommand::ConstructorArgs(cmd) => cmd.run().await?,

crates/cast/tests/cli/main.rs

@@ -6,7 +6,7 @@ use alloy_primitives::{b256, B256};
 use alloy_rpc_types::{BlockNumberOrTag, Index};
 use anvil::{EthereumHardfork, NodeConfig};
 use foundry_test_utils::{
-    casttest, file, forgetest_async,
+    casttest, file, forgetest, forgetest_async,
     rpc::{
         next_etherscan_api_key, next_http_rpc_endpoint, next_mainnet_etherscan_api_key,
         next_rpc_endpoint, next_ws_rpc_endpoint,
@@ -1547,6 +1547,60 @@ casttest!(event_decode, |_prj, cmd| {
 "#]]);
 });
 
+// tests cast can decode traces with provided signature
+casttest!(error_decode_with_sig, |_prj, cmd| {
+    cmd.args(["decode-error", "--sig", "AnotherValueTooHigh(uint256,address)", "0x7191bc6200000000000000000000000000000000000000000000000000000000000000650000000000000000000000000000000000000000000000000000000000D0004F"]).assert_success().stdout_eq(str![[r#"
+101
+0x0000000000000000000000000000000000D0004F
+
+"#]]);
+
+    cmd.args(["--json"]).assert_success().stdout_eq(str![[r#"
+[
+  "101",
+  "0x0000000000000000000000000000000000D0004F"
+]
+
+"#]]);
+});
+
+// tests cast can decode traces with Openchain API
+casttest!(error_decode_with_openchain, |_prj, cmd| {
+    cmd.args(["decode-error", "0x7a0e198500000000000000000000000000000000000000000000000000000000000000650000000000000000000000000000000000000000000000000000000000000064"]).assert_success().stdout_eq(str![[r#"
+ValueTooHigh(uint256,uint256)
+101
+100
+
+"#]]);
+});
+
+// tests cast can decode traces when using local sig identifiers cache
+forgetest!(error_decode_with_cache, |prj, cmd| {
+    foundry_test_utils::util::initialize(prj.root());
+    prj.add_source(
+        "LocalProjectContract",
+        r#"
+contract ContractWithCustomError {
+    error AnotherValueTooHigh(uint256, address);
+}
+   "#,
+    )
+    .unwrap();
+    // Store selectors in local cache.
+    cmd.forge_fuse().args(["selectors", "cache"]).assert_success();
+
+    // Assert cast can decode custom error with local cache.
+    cmd.cast_fuse()
+        .args(["decode-error", "0x7191bc6200000000000000000000000000000000000000000000000000000000000000650000000000000000000000000000000000000000000000000000000000D0004F"])
+        .assert_success()
+        .stdout_eq(str![[r#"
+AnotherValueTooHigh(uint256,address)
+101
+0x0000000000000000000000000000000000D0004F
+
+"#]]);
+});
+
 casttest!(format_units, |_prj, cmd| {
     cmd.args(["format-units", "1000000", "6"]).assert_success().stdout_eq(str![[r#"
 1

crates/cli/src/utils/cmd.rs

@@ -501,6 +501,9 @@ pub fn cache_local_signatures(output: &ProjectCompileOutput, cache_path: PathBuf
                     .events
                     .insert(event.selector().to_string(), event.full_signature());
             }
+            for error in abi.errors() {
+                cached_signatures.errors.insert(error.selector().to_string(), error.signature());
+            }
             // External libraries doesn't have functions included in abi, but `methodIdentifiers`.
             if let Some(method_identifiers) = &artifact.method_identifiers {
                 method_identifiers.iter().for_each(|(signature, selector)| {

crates/common/src/abi.rs

@@ -1,7 +1,7 @@
 //! ABI related helper functions.
 
 use alloy_dyn_abi::{DynSolType, DynSolValue, FunctionExt, JsonAbiExt};
-use alloy_json_abi::{Event, Function, Param};
+use alloy_json_abi::{Error, Event, Function, Param};
 use alloy_primitives::{hex, Address, LogData};
 use eyre::{Context, ContextCompat, Result};
 use foundry_block_explorers::{contract::ContractMetadata, errors::EtherscanError, Client};
@@ -85,6 +85,11 @@ pub fn get_event(sig: &str) -> Result<Event> {
     Event::parse(sig).wrap_err("could not parse event signature")
 }
 
+/// Given an error signature string, it tries to parse it as a `Error`
+pub fn get_error(sig: &str) -> Result<Error> {
+    Error::parse(sig).wrap_err("could not parse event signature")
+}
+
 /// Given an event without indexed parameters and a rawlog, it tries to return the event with the
 /// proper indexed parameters. Otherwise, it returns the original event.
 pub fn get_indexed_event(mut event: Event, raw_log: &LogData) -> Event {

crates/common/src/selectors.rs

@@ -140,7 +140,7 @@ impl OpenChainClient {
             .ok_or_else(|| eyre::eyre!("No signature found"))
     }
 
-    /// Decodes the given function or event selectors using OpenChain
+    /// Decodes the given function, error or event selectors using OpenChain.
     pub async fn decode_selectors(
         &self,
         selector_type: SelectorType,
@@ -164,8 +164,8 @@ impl OpenChainClient {
         self.ensure_not_spurious()?;
 
         let expected_len = match selector_type {
-            SelectorType::Function => 10, // 0x + hex(4bytes)
-            SelectorType::Event => 66,    // 0x + hex(32bytes)
+            SelectorType::Function | SelectorType::Error => 10, // 0x + hex(4bytes)
+            SelectorType::Event => 66,                          // 0x + hex(32bytes)
         };
         if let Some(s) = selectors.iter().find(|s| s.len() != expected_len) {
             eyre::bail!(
@@ -193,7 +193,7 @@ impl OpenChainClient {
         let url = format!(
             "{SELECTOR_LOOKUP_URL}?{ltype}={selectors_str}",
             ltype = match selector_type {
-                SelectorType::Function => "function",
+                SelectorType::Function | SelectorType::Error => "function",
                 SelectorType::Event => "event",
             },
             selectors_str = selectors.join(",")
@@ -212,7 +212,7 @@ impl OpenChainClient {
         }
 
         let decoded = match selector_type {
-            SelectorType::Function => api_response.result.function,
+            SelectorType::Function | SelectorType::Error => api_response.result.function,
             SelectorType::Event => api_response.result.event,
         };
 
@@ -391,6 +391,8 @@ pub enum SelectorType {
     Function,
     /// An event selector.
     Event,
+    /// An custom error selector.
+    Error,
 }
 
 /// Decodes the given function or event selector using OpenChain.

crates/evm/traces/src/identifier/signatures.rs

@@ -1,7 +1,7 @@
-use alloy_json_abi::{Event, Function};
+use alloy_json_abi::{Error, Event, Function};
 use alloy_primitives::{hex, map::HashSet};
 use foundry_common::{
-    abi::{get_event, get_func},
+    abi::{get_error, get_event, get_func},
     fs,
     selectors::{OpenChainClient, SelectorType},
 };
@@ -13,6 +13,7 @@ pub type SingleSignaturesIdentifier = Arc<RwLock<SignaturesIdentifier>>;
 
 #[derive(Debug, Default, Serialize, Deserialize)]
 pub struct CachedSignatures {
+    pub errors: BTreeMap<String, String>,
     pub events: BTreeMap<String, String>,
     pub functions: BTreeMap<String, String>,
 }
@@ -39,7 +40,7 @@ impl CachedSignatures {
 /// `https://openchain.xyz` or a local cache.
 #[derive(Debug)]
 pub struct SignaturesIdentifier {
-    /// Cached selectors for functions and events.
+    /// Cached selectors for functions, events and custom errors.
     cached: CachedSignatures,
     /// Location where to save `CachedSignatures`.
     cached_path: Option<PathBuf>,
@@ -101,6 +102,7 @@ impl SignaturesIdentifier {
         let cache = match selector_type {
             SelectorType::Function => &mut self.cached.functions,
             SelectorType::Event => &mut self.cached.events,
+            SelectorType::Error => &mut self.cached.errors,
         };
 
         let hex_identifiers: Vec<String> =
@@ -157,6 +159,19 @@ impl SignaturesIdentifier {
     pub async fn identify_event(&mut self, identifier: &[u8]) -> Option<Event> {
         self.identify_events(&[identifier]).await.pop().unwrap()
     }
+
+    /// Identifies `Error`s from its cache or `https://api.openchain.xyz`.
+    pub async fn identify_errors(
+        &mut self,
+        identifiers: impl IntoIterator<Item = impl AsRef<[u8]>>,
+    ) -> Vec<Option<Error>> {
+        self.identify(SelectorType::Error, identifiers, get_error).await
+    }
+
+    /// Identifies `Error` from its cache or `https://api.openchain.xyz`.
+    pub async fn identify_error(&mut self, identifier: &[u8]) -> Option<Error> {
+        self.identify_errors(&[identifier]).await.pop().unwrap()
+    }
 }
 
 impl Drop for SignaturesIdentifier {