From c70cd81de01c6edd2852c00ef1f2900f2b31d827 Mon Sep 17 00:00:00 2001
From: James Prestwich <10149425+prestwich@users.noreply.github.com>
Date: Thu, 5 May 2022 07:22:47 -0700
Subject: [PATCH] feature: pending transaction retries repeatedly before
 assuming dropped (#1221)

---
 CHANGELOG.md                                |  2 ++
 ethers-providers/src/pending_transaction.rs | 22 ++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5def5468..810d78da 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -153,6 +153,8 @@
 
 ### Unreleased
 
+- Add retries to the pending transaction future
+  [1221](https://github.com/gakonst/ethers-rs/pull/1221)
 - Add support for basic and bearer authentication in http and non-wasm websockets.
   [829](https://github.com/gakonst/ethers-rs/pull/829)
 - Export `ethers_providers::IpcError` and `ethers_providers::QuorumError`
diff --git a/ethers-providers/src/pending_transaction.rs b/ethers-providers/src/pending_transaction.rs
index 0e1a8bef..17451b7e 100644
--- a/ethers-providers/src/pending_transaction.rs
+++ b/ethers-providers/src/pending_transaction.rs
@@ -62,8 +62,11 @@ pub struct PendingTransaction<'a, P> {
     provider: &'a Provider<P>,
     state: PendingTxState<'a>,
     interval: Box<dyn Stream<Item = ()> + Send + Unpin>,
+    retries_remaining: usize,
 }
 
+const DEFAULT_RETRIES: usize = 3;
+
 impl<'a, P: JsonRpcClient> PendingTransaction<'a, P> {
     /// Creates a new pending transaction poller from a hash and a provider
     pub fn new(tx_hash: TxHash, provider: &'a Provider<P>) -> Self {
@@ -74,6 +77,7 @@ impl<'a, P: JsonRpcClient> PendingTransaction<'a, P> {
             provider,
             state: PendingTxState::InitialDelay(delay),
             interval: Box::new(interval(DEFAULT_POLL_INTERVAL)),
+            retries_remaining: DEFAULT_RETRIES,
         }
     }
 
@@ -111,6 +115,13 @@ impl<'a, P: JsonRpcClient> PendingTransaction<'a, P> {
 
         self
     }
+
+    /// Set retries
+    #[must_use]
+    pub fn retries(mut self, retries: usize) -> Self {
+        self.retries_remaining = retries;
+        self
+    }
 }
 
 impl<'a, P> PendingTransaction<'a, P> {
@@ -188,9 +199,14 @@ impl<'a, P: JsonRpcClient> Future for PendingTransaction<'a, P> {
                 let tx_opt = tx_res.unwrap();
                 // If the tx is no longer in the mempool, return Ok(None)
                 if tx_opt.is_none() {
-                    tracing::debug!("Dropped from mempool, pending tx {:?}", *this.tx_hash);
-                    *this.state = PendingTxState::Completed;
-                    return Poll::Ready(Ok(None))
+                    if *this.retries_remaining == 0 {
+                        tracing::debug!("Dropped from mempool, pending tx {:?}", *this.tx_hash);
+                        *this.state = PendingTxState::Completed;
+                        return Poll::Ready(Ok(None))
+                    }
+
+                    *this.retries_remaining -= 1;
+                    rewake_with_new_state!(ctx, this, PendingTxState::PausedGettingTx);
                 }
 
                 // If it hasn't confirmed yet, poll again later