fix: decode events for 0-sized contracts (#1317)

cli/src/cmd/forge/run.rs

@@ -20,7 +20,7 @@ use forge::{
         builder::Backend, opts::EvmOpts, CallResult, DatabaseRef, DeployResult, EvmError, Executor,
         ExecutorBuilder, RawCallResult,
     },
-    trace::{identifier::LocalTraceIdentifier, CallTraceArena, CallTraceDecoder, TraceKind},
+    trace::{identifier::LocalTraceIdentifier, CallTraceArena, CallTraceDecoderBuilder, TraceKind},
     CALLER,
 };
 use foundry_common::evm::EvmArgs;
@@ -162,7 +162,10 @@ impl Cmd for RunArgs {
         // bytecode. Might be better to wait for an interactive debugger where we can do this on
         // the fly while retaining access to the database?
         let local_identifier = LocalTraceIdentifier::new(&known_contracts);
-        let mut decoder = CallTraceDecoder::new_with_labels(result.labeled_addresses.clone());
+        let mut decoder = CallTraceDecoderBuilder::new()
+            .with_labels(result.labeled_addresses.clone())
+            .with_events(local_identifier.events())
+            .build();
         for (_, trace) in &mut result.traces {
             decoder.identify(trace, &local_identifier);
         }

cli/src/cmd/forge/test.rs

@@ -17,7 +17,7 @@ use forge::{
     gas_report::GasReport,
     trace::{
         identifier::{EtherscanIdentifier, LocalTraceIdentifier},
-        CallTraceDecoder, TraceKind,
+        CallTraceDecoderBuilder, TraceKind,
     },
     MultiContractRunner, MultiContractRunnerBuilder, SuiteResult, TestFilter, TestKind,
 };
@@ -521,8 +521,10 @@ fn test(
 
                 if !result.traces.is_empty() {
                     // Identify addresses in each trace
-                    let mut decoder =
-                        CallTraceDecoder::new_with_labels(result.labeled_addresses.clone());
+                    let mut decoder = CallTraceDecoderBuilder::new()
+                        .with_labels(result.labeled_addresses.clone())
+                        .with_events(local_identifier.events())
+                        .build();
 
                     // Decode the traces
                     let mut decoded_traces = Vec::new();

evm/src/trace/decoder.rs

@@ -12,6 +12,42 @@ use ethers::{
 };
 use std::collections::{BTreeMap, HashMap};
 
+/// Build a new [CallTraceDecoder].
+#[derive(Default)]
+pub struct CallTraceDecoderBuilder {
+    decoder: CallTraceDecoder,
+}
+
+impl CallTraceDecoderBuilder {
+    pub fn new() -> Self {
+        Self { decoder: CallTraceDecoder::new() }
+    }
+
+    /// Add known labels to the decoder.
+    pub fn with_labels(mut self, labels: BTreeMap<Address, String>) -> Self {
+        for (address, label) in labels.into_iter() {
+            self.decoder.labels.insert(address, label);
+        }
+        self
+    }
+
+    /// Add known events to the decoder.
+    pub fn with_events(mut self, events: Vec<Event>) -> Self {
+        events
+            .into_iter()
+            .map(|event| ((event.signature(), indexed_inputs(&event)), event))
+            .for_each(|(sig, event)| {
+                self.decoder.events.entry(sig).or_default().push(event);
+            });
+        self
+    }
+
+    /// Build the decoder.
+    pub fn build(self) -> CallTraceDecoder {
+        self.decoder
+    }
+}
+
 /// The call trace decoder.
 ///
 /// The decoder collects address labels and ABIs from any number of [TraceIdentifier]s, which it
@@ -130,15 +166,6 @@ impl CallTraceDecoder {
         }
     }
 
-    /// Creates a new call trace decoder with predetermined address labels.
-    pub fn new_with_labels(labels: BTreeMap<Address, String>) -> Self {
-        let mut info = Self::new();
-        for (address, label) in labels.into_iter() {
-            info.labels.insert(address, label);
-        }
-        info
-    }
-
     /// Identify unknown addresses in the specified call trace using the specified identifier.
     ///
     /// Unknown contracts are contracts that either lack a label or an ABI.

evm/src/trace/identifier/local.rs

@@ -1,6 +1,6 @@
 use super::{AddressIdentity, TraceIdentifier};
 use ethers::{
-    abi::{Abi, Address},
+    abi::{Abi, Address, Event},
     prelude::ArtifactId,
 };
 use std::{borrow::Cow, collections::BTreeMap};
@@ -21,6 +21,11 @@ impl LocalTraceIdentifier {
                 .collect(),
         }
     }
+
+    /// Get all the events of the local contracts.
+    pub fn events(&self) -> Vec<Event> {
+        self.local_contracts.iter().flat_map(|(_, (_, abi))| abi.events().cloned()).collect()
+    }
 }
 
 impl TraceIdentifier for LocalTraceIdentifier {

evm/src/trace/mod.rs

@@ -7,7 +7,7 @@ mod decoder;
 mod node;
 mod utils;
 
-pub use decoder::CallTraceDecoder;
+pub use decoder::{CallTraceDecoder, CallTraceDecoderBuilder};
 
 use crate::{abi::CHEATCODE_ADDRESS, CallKind};
 use ansi_term::Colour;