fix: only expect signet blocks to adhere to slot timing rules (#61)

* fix: only expect signet blocks to adhere to slot timing rules

This commit only expects slot adherence for Signet blocks to avoid
checking pre-merge blocks which panics because of non-deterministic
slot times for Proof of Work blocks.

* dpes: bump version to rc.4

Author: dylanlott

Cargo.toml

@@ -3,7 +3,7 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.package]
-version = "0.16.0-rc.3"
+version = "0.16.0-rc.4"
 edition = "2024"
 rust-version = "1.88"
 authors = ["init4"]

crates/block-processor/src/v1/processor.rs

@@ -248,10 +248,13 @@ where
             .wrap_err("parent ru block not present in DB")
             .inspect_err(|e| error!(%e))?;
 
-        let slot = self.slot_calculator.slot_ending_at(timestamp).expect("host chain has started");
-
         let txns = match &block_extracts.submitted {
             Some(submitted) => {
+                // NB: Pre-merge blocks do not have predictable slot times.
+                let slot = self
+                    .slot_calculator
+                    .slot_ending_at(timestamp)
+                    .expect("expect submitted events only occur post-merge");
                 self.blob_cacher
                     .signet_block(block_extracts.host_block.number(), slot, submitted)
                     .await?