fix an issue in restore results

Signed-off-by: noelwei <fan@scroll.io>

integration/src/prove.rs

@@ -2,6 +2,7 @@ use halo2_proofs::{halo2curves::bn256::Bn256, poly::kzg::commitment::ParamsKZG};
 use prover::{
     aggregator::Prover as BatchProver, zkevm::Prover as ChunkProver, BatchData, BatchProof,
     BatchProvingTask, BundleProvingTask, ChunkInfo, ChunkProof, ChunkProvingTask, MAX_AGG_SNARKS,
+    Proof as CommonProof,
 };
 use std::{collections::BTreeMap, env, time::Instant};
 
@@ -64,18 +65,41 @@ impl<'params> SP1Prover<'params> {
             output_dir,
         )?;
 
-        let result = ChunkProof::new(
-            comp_snark,
-            self.0.prover_impl.pk(Layer2.id()),
-            chunk_info,
-            Vec::new(),
-        );
+        let pk = self.0.prover_impl.pk(Layer2.id());
+        // in case we read the snark directly from previous calculation,
+        // the pk is not avaliable and we use a work-around to construct
+        // the proof (and dumping is not needed)
+        if pk.is_none() {
+            log::info!("restore chunk_snark {chunk_identifier:?} from disk");
+            // vk must be loaded (dumped along with snark together) in this case
+            assert!(self.0.get_vk().is_some());
+            let protocol = serde_json::to_vec(&comp_snark.protocol)?;
+            let proof = CommonProof::from_snark(
+                comp_snark,
+                self.0.get_vk().expect("checked"),
+            );
+
+            Ok(ChunkProof {
+                proof,
+                protocol,
+                chunk_info,
+                row_usages: Vec::new(),
+            })
 
-        if let (Some(output_dir), Ok(proof)) = (output_dir, &result) {
-            proof.dump(output_dir, chunk_identifier)?;
+        } else {
+            let result = ChunkProof::new(
+                comp_snark,
+                pk,
+                chunk_info,
+                Vec::new(),
+            );
+
+            if let (Some(output_dir), Ok(proof)) = (output_dir, &result) {
+                proof.dump(output_dir, chunk_identifier)?;
+            }
+
+            result
         }
-
-        result
     }
 }