fix: skip db consolidation if no new dataset was downloaded (#513)

### Description

The database consolidation loop doesn't need to happen if there is no
new data.

@lgalabru I'm interested in your thoughts on this. Potentially someone
could break their stacks.rocksdb, then Chainhook wouldn't automatically
fix it unless they deleted their archive to force a redownload, or a new
archive becomes available.

I think the tradeoff is worth it because of the improvements to startup
time if users are repeatedly running `chainhook predicates scan`, or if
the service goes down and needs to restart.

---------

Co-authored-by: Chris Guimarães <cguimaraes.br@gmail.com>

components/chainhook-cli/src/scan/stacks.rs

@@ -516,59 +516,66 @@ pub async fn consolidate_local_stacks_chainstate_using_csv(
         "Building local chainstate from Stacks archive file"
     );
 
-    let _ = download_stacks_dataset_if_required(config, ctx).await;
-
-    let stacks_db = open_readonly_stacks_db_conn_with_retry(&config.expected_cache_path(), 3, ctx)?;
-    let confirmed_tip = get_last_block_height_inserted(&stacks_db, &ctx);
-    let mut canonical_fork = get_canonical_fork_from_tsv(config, confirmed_tip, ctx).await?;
-
-    let mut indexer = Indexer::new(config.network.clone());
-    let mut blocks_inserted = 0;
-    let mut blocks_read = 0;
-    let blocks_to_insert = canonical_fork.len();
-    let stacks_db_rw = open_readwrite_stacks_db_conn(&config.expected_cache_path(), ctx)?;
-    info!(
-        ctx.expect_logger(),
-        "Begining import of {} Stacks blocks into rocks db", blocks_to_insert
-    );
-    for (block_identifier, _parent_block_identifier, blob) in canonical_fork.drain(..) {
-        blocks_read += 1;
-
-        // If blocks already stored, move on
-        if is_stacks_block_present(&block_identifier, 3, &stacks_db_rw) {
-            continue;
-        }
-        blocks_inserted += 1;
+    let downloaded_new_dataset = download_stacks_dataset_if_required(config, ctx).await;
+
+    if downloaded_new_dataset {
+        let stacks_db =
+            open_readonly_stacks_db_conn_with_retry(&config.expected_cache_path(), 3, ctx)?;
+        let confirmed_tip = get_last_block_height_inserted(&stacks_db, &ctx);
+        let mut canonical_fork = get_canonical_fork_from_tsv(config, confirmed_tip, ctx).await?;
+
+        let mut indexer = Indexer::new(config.network.clone());
+        let mut blocks_inserted = 0;
+        let mut blocks_read = 0;
+        let blocks_to_insert = canonical_fork.len();
+        let stacks_db_rw = open_readwrite_stacks_db_conn(&config.expected_cache_path(), ctx)?;
+        info!(
+            ctx.expect_logger(),
+            "Beginning import of {} Stacks blocks into rocks db", blocks_to_insert
+        );
+        for (block_identifier, _parent_block_identifier, blob) in canonical_fork.drain(..) {
+            blocks_read += 1;
 
-        let block_data = match indexer::stacks::standardize_stacks_serialized_block(
-            &indexer.config,
-            &blob,
-            &mut indexer.stacks_context,
-            ctx,
-        ) {
-            Ok(block) => block,
-            Err(e) => {
-                error!(&ctx.expect_logger(), "{e}");
+            // If blocks already stored, move on
+            if is_stacks_block_present(&block_identifier, 3, &stacks_db_rw) {
                 continue;
             }
-        };
+            blocks_inserted += 1;
 
-        // TODO: return a result
-        insert_entry_in_stacks_blocks(&block_data, &stacks_db_rw, ctx);
+            let block_data = match indexer::stacks::standardize_stacks_serialized_block(
+                &indexer.config,
+                &blob,
+                &mut indexer.stacks_context,
+                ctx,
+            ) {
+                Ok(block) => block,
+                Err(e) => {
+                    error!(&ctx.expect_logger(), "{e}");
+                    continue;
+                }
+            };
 
-        if blocks_inserted % 2500 == 0 {
-            info!(
-                ctx.expect_logger(),
-                "Importing Stacks blocks into rocks db: {}/{}", blocks_read, blocks_to_insert
-            );
-            let _ = stacks_db_rw.flush();
+            // TODO: return a result
+            insert_entry_in_stacks_blocks(&block_data, &stacks_db_rw, ctx);
+
+            if blocks_inserted % 2500 == 0 {
+                info!(
+                    ctx.expect_logger(),
+                    "Importing Stacks blocks into rocks db: {}/{}", blocks_read, blocks_to_insert
+                );
+                let _ = stacks_db_rw.flush();
+            }
         }
+        let _ = stacks_db_rw.flush();
+        info!(
+            ctx.expect_logger(),
+            "{blocks_read} Stacks blocks read, {blocks_inserted} inserted"
+        );
+    } else {
+        info!(
+            ctx.expect_logger(),
+            "Skipping database consolidation - no new archive found since last consolidation."
+        );
     }
-    let _ = stacks_db_rw.flush();
-    info!(
-        ctx.expect_logger(),
-        "{blocks_read} Stacks blocks read, {blocks_inserted} inserted"
-    );
-
     Ok(())
 }