log errors in more detail when block production fails (#2135)

* log errors in more detail when block production fails

* pass through block header error

* make everything cstring

beacon_chain/spec/state_transition.nim

@@ -177,7 +177,8 @@ proc state_transition*(
     trace "state_transition: processing block, signature passed",
       signature = shortLog(signedBlock.signature),
       blockRoot = shortLog(signedBlock.root)
-    if process_block(preset, state.data, signedBlock.message, flags, stateCache):
+    let res = process_block(preset, state.data, signedBlock.message, flags, stateCache)
+    if res.isOk:
       if skipStateRootValidation in flags or verifyStateRoot(state.data, signedBlock.message):
         # State root is what it should be - we're done!
 
@@ -190,6 +191,13 @@ proc state_transition*(
           else: signedBlock.message.state_root
 
         return true
+    else:
+      debug "state_transition: process_block failed",
+        blck = shortLog(signedBlock.message),
+        slot = state.data.slot,
+        eth1_deposit_index = state.data.eth1_deposit_index,
+        deposit_root = shortLog(state.data.eth1_data.deposit_root),
+        error = res.error
 
   # Block processing failed, roll back changes
   rollback(state)
@@ -236,10 +244,15 @@ proc makeBeaconBlock*(
       voluntary_exits:
         List[SignedVoluntaryExit, Limit MAX_VOLUNTARY_EXITS](voluntaryExits)))
 
-  let ok = process_block(preset, state.data, blck, {skipBlsValidation}, cache)
+  let res = process_block(preset, state.data, blck, {skipBlsValidation}, cache)
 
-  if not ok:
+  if res.isErr:
-    warn "Unable to apply new block to state", blck = shortLog(blck)
+    warn "Unable to apply new block to state",
+      blck = shortLog(blck),
+      slot = state.data.slot,
+      eth1_deposit_index = state.data.eth1_deposit_index,
+      deposit_root = shortLog(state.data.eth1_data.deposit_root),
+      error = res.error
     rollback(state)
     return
 

beacon_chain/spec/state_transition_block.nim

@@ -342,33 +342,20 @@ proc process_operations(preset: RuntimePreset,
 proc process_block*(
     preset: RuntimePreset,
     state: var BeaconState, blck: SomeBeaconBlock, flags: UpdateFlags,
-    stateCache: var StateCache): bool {.nbench.}=
+    stateCache: var StateCache): Result[void, cstring] {.nbench.}=
   ## When there's a new block, we need to verify that the block is sane and
   ## update the state accordingly - the state is left in an unknown state when
   ## block application fails (!)
 
-  logScope:
+  ? process_block_header(state, blck, flags, stateCache)
-    blck = shortLog(blck)
-  let res_block = process_block_header(state, blck, flags, stateCache)
-  if res_block.isErr:
-    debug "Block header not valid",
-      block_header_error = $(res_block.error),
-      slot = state.slot
-    return false
 
   if not process_randao(state, blck.body, flags, stateCache):
-    debug "Randao failure", slot = shortLog(state.slot)
+    return err("Randao failure".cstring)
-    return false
 
   process_eth1_data(state, blck.body)
 
   let res_ops = process_operations(preset, state, blck.body, flags, stateCache)
   if res_ops.isErr:
-    debug "process_operations encountered error",
+    return err("process_operations encountered error".cstring)
-      operation_error = $(res_ops.error),
-      slot = state.slot,
-      eth1_deposit_index = state.eth1_deposit_index,
-      deposit_root = shortLog(state.eth1_data.deposit_root)
-    return false
 
-  true
+  ok()