From 7ea92dee255517b57ae6b188d15ba7fc05b510d3 Mon Sep 17 00:00:00 2001
From: Nazar Mokrynskyi <nazar@mokrynskyi.com>
Date: Thu, 28 Nov 2024 06:06:00 +0200
Subject: [PATCH] Fix fresh node start with Snap sync failing

---
 crates/sc-consensus-subspace/src/archiver.rs | 42 ++++++++++++--------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/crates/sc-consensus-subspace/src/archiver.rs b/crates/sc-consensus-subspace/src/archiver.rs
index 075fabc162..ba7a860c29 100644
--- a/crates/sc-consensus-subspace/src/archiver.rs
+++ b/crates/sc-consensus-subspace/src/archiver.rs
@@ -631,28 +631,38 @@ where
     }
 
     // If the user chooses an object mapping start block we don't have data or state for, we can't
-    // create mappings for it, so the node must exit with an error.
-    let best_block_to_archive_hash = client
-        .hash(best_block_to_archive.into())?
-        .expect("just checked above; qed");
-    let Some(best_block_data) = client.block(best_block_to_archive_hash)? else {
-        let error = format!(
-                "Missing data for mapping block {best_block_to_archive} hash {best_block_to_archive_hash}, \
-                try a higher block number, or wipe your node and restart with `--sync full`"
+    // create mappings for it, so the node must exit with an error
+    if create_object_mappings.is_enabled() {
+        let best_block_to_archive_hash = client
+            .hash(best_block_to_archive.into())?
+            .expect("just checked above; qed");
+        let Some(best_block_data) = client.block(best_block_to_archive_hash)? else {
+            let error = format!(
+                "Missing data for mapping block {best_block_to_archive} hash \
+                {best_block_to_archive_hash}, try a higher block number, or wipe your node and \
+                restart with `--sync full`"
             );
-        return Err(sp_blockchain::Error::Application(error.into()));
-    };
+            return Err(sp_blockchain::Error::Application(error.into()));
+        };
 
-    // Similarly, state can be pruned, even if the data is present.
-    client
-        .runtime_api()
-        .extract_block_object_mapping(*best_block_data.block.header().parent_hash(), best_block_data.block.clone())
+        // Similarly, state can be pruned, even if the data is present
+        client
+            .runtime_api()
+            .extract_block_object_mapping(
+                *best_block_data.block.header().parent_hash(),
+                best_block_data.block.clone(),
+            )
             .map_err(|error| {
                 sp_blockchain::Error::Application(
-                    format!("Missing state for mapping block {best_block_to_archive} hash {best_block_to_archive_hash}: {error}, \
-                            try a higher block number, or wipe your node and restart with `--sync full`").into(),
+                    format!(
+                        "Missing state for mapping block {best_block_to_archive} hash \
+                        {best_block_to_archive_hash}: {error}, try a higher block number, or wipe \
+                        your node and restart with `--sync full`"
+                    )
+                    .into(),
                 )
             })?;
+    }
 
     let maybe_last_archived_block = find_last_archived_block(
         client,