From 682942d3b0330eaa1d4bfa8485781fa06a0084d9 Mon Sep 17 00:00:00 2001
From: Tamir Hemo <tamir@succinct.xyz>
Date: Mon, 30 Sep 2024 16:22:59 -0700
Subject: [PATCH] fix: execution shard initialization  (#1576)

---
 crates/recursion/circuit-v2/src/machine/compress.rs | 7 ++++++-
 crates/recursion/circuit-v2/src/machine/core.rs     | 2 --
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/crates/recursion/circuit-v2/src/machine/compress.rs b/crates/recursion/circuit-v2/src/machine/compress.rs
index 6e5abdd0ef..561e0f5722 100644
--- a/crates/recursion/circuit-v2/src/machine/compress.rs
+++ b/crates/recursion/circuit-v2/src/machine/compress.rs
@@ -316,12 +316,17 @@ where
                         * (SymbolicFelt::one() - contains_execution_shard),
                 );
 
-                // If this is the first execution shard, then we update the start execution shard.
+                // If this is the first execution shard, then we update the start execution shard
+                // and the `execution_shard` values.
                 compress_public_values.start_execution_shard = builder.eval(
                     current_public_values.start_execution_shard * is_first_execution_shard_seen
                         + compress_public_values.start_execution_shard
                             * (SymbolicFelt::one() - is_first_execution_shard_seen),
                 );
+                execution_shard = builder.eval(
+                    current_public_values.start_execution_shard * is_first_execution_shard_seen
+                        + execution_shard * (SymbolicFelt::one() - is_first_execution_shard_seen),
+                );
 
                 // If this is an execution shard, make the assertion that the value is consistent.
                 builder.assert_felt_eq(
diff --git a/crates/recursion/circuit-v2/src/machine/core.rs b/crates/recursion/circuit-v2/src/machine/core.rs
index 4dd813f2b8..fb4b38fcd8 100644
--- a/crates/recursion/circuit-v2/src/machine/core.rs
+++ b/crates/recursion/circuit-v2/src/machine/core.rs
@@ -187,8 +187,6 @@ where
             let public_values: &PublicValues<Word<Felt<_>>, Felt<_>> =
                 shard_proof.public_values.as_slice().borrow();
 
-            let _shard = public_values.shard;
-
             // If this is the first proof in the batch, initialize the variables.
             if i == 0 {
                 // Shard.