Move BeaconBlockNil Checker Function to Consensus-Types/Wrapper Package (#10731)

* beacon block is nil wrapper

* gaz

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

consensus-types/wrapper/beacon_block.go

@@ -32,7 +32,10 @@ var (
 	// ErrUnsupportedBlindedBellatrixBlock is returned when accessing a blinded bellatrix block from unsupported method.
 	ErrUnsupportedBlindedBellatrixBlock = errors.New("unsupported blinded bellatrix block")
 	// ErrNilObjectWrapped is returned in a constructor when the underlying object is nil.
-	ErrNilObjectWrapped = errors.New("attempted to wrap nil object")
+	ErrNilObjectWrapped     = errors.New("attempted to wrap nil object")
+	ErrNilSignedBeaconBlock = errors.New("signed beacon block can't be nil")
+	ErrNilBeaconBlock       = errors.New("beacon block can't be nil")
+	ErrNilBeaconBlockBody   = errors.New("beacon block body can't be nil")
 )
 
 // WrappedSignedBeaconBlock will wrap a signed beacon block to conform to the
@@ -159,3 +162,19 @@ func UnwrapGenericSignedBeaconBlock(gb *eth.GenericSignedBeaconBlock) (interface
 		return nil, errors.Wrapf(ErrUnsupportedSignedBeaconBlock, "unable to wrap block of type %T", gb)
 	}
 }
+
+// BeaconBlockIsNil checks if any composite field of input signed beacon block is nil.
+// Access to these nil fields will result in run time panic,
+// it is recommended to run these checks as first line of defense.
+func BeaconBlockIsNil(b interfaces.SignedBeaconBlock) error {
+	if b == nil || b.IsNil() {
+		return ErrNilSignedBeaconBlock
+	}
+	if b.Block().IsNil() {
+		return ErrNilBeaconBlock
+	}
+	if b.Block().Body().IsNil() {
+		return ErrNilBeaconBlockBody
+	}
+	return nil
+}