From 7a0dbd1d2424e20efb9e9d254981ec211f183dcf Mon Sep 17 00:00:00 2001
From: Richard Watts <richard@zilliqa.com>
Date: Mon, 23 Dec 2024 18:29:48 +0000
Subject: [PATCH] (feat) Start of an exception list

---
 bridge-validators/src/block.rs      |  7 ++++++-
 bridge-validators/src/client.rs     |  4 +++-
 bridge-validators/src/exceptions.rs | 18 ++++++++++++++++++
 bridge-validators/src/main.rs       |  1 +
 4 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 bridge-validators/src/exceptions.rs

diff --git a/bridge-validators/src/block.rs b/bridge-validators/src/block.rs
index 8fc8d28..14b61f8 100644
--- a/bridge-validators/src/block.rs
+++ b/bridge-validators/src/block.rs
@@ -112,7 +112,11 @@ impl ChainClient {
                             }
                             if matches {
                                 info!("Event matches; pushing for transit");
-                                result.push(log);
+                                if let Some(v) = self.except.transform_log(&log) {
+                                    result.push(v);
+                                } else {
+                                    info!("Log {log:?} could not be sent for transit due transform_log() failure");
+                                }
                             }
                         }
                     } else {
@@ -202,6 +206,7 @@ impl BlockPolling for ChainClient {
 
         let events: Vec<D> = logs
             .into_iter()
+            .filter_map(|log| self.except.transform_log(&log))
             .map(|log| Ok(parse_log::<D>(log)?))
             .collect::<Result<Vec<D>>>()?;
 
diff --git a/bridge-validators/src/client.rs b/bridge-validators/src/client.rs
index f2dc13a..77a25ac 100644
--- a/bridge-validators/src/client.rs
+++ b/bridge-validators/src/client.rs
@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use crate::{ChainGateway, ValidatorManager};
+use crate::{exceptions, ChainGateway, ValidatorManager};
 use anyhow::Result;
 use ethers::{
     middleware::{MiddlewareBuilder, NonceManagerMiddleware, SignerMiddleware},
@@ -37,6 +37,7 @@ pub struct ChainClient {
     pub scan_behind_blocks: u64,
     pub log_strategy: LogStrategy,
     pub to_block_number: Option<u64>,
+    pub except: exceptions::ExceptionProcessor,
 }
 
 impl fmt::Display for ChainClient {
@@ -106,6 +107,7 @@ impl ChainClient {
             scan_behind_blocks: config.scan_behind_blocks.unwrap_or_default(),
             log_strategy: strategy,
             to_block_number: config.to_block_number,
+            except: exceptions::ExceptionProcessor::new(),
         })
     }
 }
diff --git a/bridge-validators/src/exceptions.rs b/bridge-validators/src/exceptions.rs
new file mode 100644
index 0000000..da0d923
--- /dev/null
+++ b/bridge-validators/src/exceptions.rs
@@ -0,0 +1,18 @@
+use ethers::types::Log;
+
+/// The exception processor handles exceptions - these are txns which were issued in error, usually as a result
+/// of a bug in the relayer contracts; their parameters are corrected here before being passed on to the rest of
+/// the relayer logic for execution.
+#[derive(Debug, Clone)]
+pub struct ExceptionProcessor {}
+
+impl ExceptionProcessor {
+    pub fn new() -> Self {
+        ExceptionProcessor {}
+    }
+
+    // We'll warn!() if we have to drop a log.
+    pub fn transform_log(&self, log: &Log) -> Option<Log> {
+        Some(log.clone())
+    }
+}
diff --git a/bridge-validators/src/main.rs b/bridge-validators/src/main.rs
index 00dfc7b..85443b2 100644
--- a/bridge-validators/src/main.rs
+++ b/bridge-validators/src/main.rs
@@ -3,6 +3,7 @@ mod bridge_node;
 mod client;
 mod crypto;
 mod event;
+mod exceptions;
 mod message;
 mod p2p_node;
 mod signature;