Prunes non-empty shard

[emhane]

Describe the feature

Passing the check blocks.len() as usize != new_blocks.len() means that if new_blocks is empty, then blocks is non-empty. Hence, shards are being deleted that contain blocks that are higher than the target block. The target block is used to filter out blocks to give new_blocks vector.

reth/crates/prune/src/segments/history.rs

Lines 59 to 100 in e4f34e7

	// If there were blocks less than or equal to the target one
	// (so the shard has changed), update the shard.
	if blocks.len() as usize != new_blocks.len() {
	// If there are no more blocks in this shard, we need to remove it, as empty
	// shards are not allowed.
	if new_blocks.is_empty() {
	if key.as_ref().highest_block_number == u64::MAX {
	let prev_row = cursor.prev()?;
	match prev_row {
	// If current shard is the last shard for the sharded key that
	// has previous shards, replace it with the previous shard.
	Some((prev_key, prev_value)) if key_matches(&prev_key, &key) => {
	cursor.delete_current()?;
	deleted += 1;
	// Upsert will replace the last shard for this sharded key with
	// the previous value.
	cursor.upsert(key.clone(), prev_value)?;
	}
	// If there's no previous shard for this sharded key,
	// just delete last shard completely.
	_ => {
	// If we successfully moved the cursor to a previous row,
	// jump to the original last shard.
	if prev_row.is_some() {
	cursor.next()?;
	}
	// Delete shard.
	cursor.delete_current()?;
	deleted += 1;
	}
	}
	}
	// If current shard is not the last shard for this sharded key,
	// just delete it.
	else {
	cursor.delete_current()?;
	deleted += 1;
	}
	} else {
	cursor.upsert(key.clone(), BlockNumberList::new_pre_sorted(new_blocks))?;
	}
	}

reth/crates/prune/src/segments/history.rs

Lines 56 to 57 in e4f34e7

	let new_blocks =
	blocks.iter().skip_while(|block| *block <= to_block).collect::<Vec<_>>();

Additional context

No response