From d665d2a12cb5bfc48c20a78e162b3e1365d74210 Mon Sep 17 00:00:00 2001
From: Mononaut <github@monospace.live>
Date: Sat, 6 Jan 2024 03:42:45 +0000
Subject: [PATCH] Handle unmineable transactions in GBT implementations

---
 backend/rust-gbt/src/gbt.rs            | 11 +++++++----
 backend/src/api/tx-selection-worker.ts |  3 +++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/backend/rust-gbt/src/gbt.rs b/backend/rust-gbt/src/gbt.rs
index fb28dc299..412d4e5e9 100644
--- a/backend/rust-gbt/src/gbt.rs
+++ b/backend/rust-gbt/src/gbt.rs
@@ -127,7 +127,7 @@ pub fn gbt(mempool: &mut ThreadTransactionsMap, accelerations: &[ThreadAccelerat
         let next_from_stack = next_valid_from_stack(&mut mempool_stack, &audit_pool);
         let next_from_queue = next_valid_from_queue(&mut modified, &audit_pool);
         if next_from_stack.is_none() && next_from_queue.is_none() {
-            continue;
+            break;
         }
         let (next_tx, from_stack) = match (next_from_stack, next_from_queue) {
             (Some(stack_tx), Some(queue_tx)) => match queue_tx.cmp(stack_tx) {
@@ -203,10 +203,13 @@ pub fn gbt(mempool: &mut ThreadTransactionsMap, accelerations: &[ThreadAccelerat
         let queue_is_empty = mempool_stack.is_empty() && modified.is_empty();
         if (exceeded_package_tries || queue_is_empty) && blocks.len() < (MAX_BLOCKS - 1) {
             // finalize this block
-            if !transactions.is_empty() {
-                blocks.push(transactions);
-                block_weights.push(block_weight);
+            if transactions.is_empty() {
+                break;
             }
+
+            blocks.push(transactions);
+            block_weights.push(block_weight);
+
             // reset for the next block
             transactions = Vec::with_capacity(initial_txes_per_block);
             block_weight = BLOCK_RESERVED_WEIGHT;
diff --git a/backend/src/api/tx-selection-worker.ts b/backend/src/api/tx-selection-worker.ts
index 0acc2f65e..8ac7328fe 100644
--- a/backend/src/api/tx-selection-worker.ts
+++ b/backend/src/api/tx-selection-worker.ts
@@ -173,10 +173,13 @@ function makeBlockTemplates(mempool: Map<number, CompactThreadTransaction>)
     // this block is full
     const exceededPackageTries = failures > 1000 && blockWeight > (config.MEMPOOL.BLOCK_WEIGHT_UNITS - 4000);
     const queueEmpty = top >= mempoolArray.length && modified.isEmpty();
+
     if ((exceededPackageTries || queueEmpty) && blocks.length < 7) {
       // construct this block
       if (transactions.length) {
         blocks.push(transactions.map(t => t.uid));
+      } else {
+        break;
       }
       // reset for the next block
       transactions = [];