fix panic on substreams-tier2 service

CHANGELOG.md

@@ -8,6 +8,10 @@ Operators, you should copy/paste content of this content straight to your projec
 
 If you were at `firehose-core` version `1.0.0` and are bumping to `1.1.0`, you should copy the content between those 2 version to your own repository, replacing placeholder value `fire{chain}` with your chain's own binary.
 
+## v1.3.1
+
+* fix panic on substreams-tier2 service
+
 ## v1.3.0
 
 ### Substreams

cmd/apps/substreams_tier2.go

@@ -26,6 +26,7 @@ import (
 	"github.com/streamingfast/firehose-core/launcher"
 	"github.com/streamingfast/logging"
 	"github.com/streamingfast/substreams/app"
+	"github.com/streamingfast/substreams/wasm"
 	"go.uber.org/zap"
 )
 
@@ -71,9 +72,13 @@ func RegisterSubstreamsTier2App[B firecore.Block](chain *firecore.Chain[B], root
 				serviceDiscoveryURL = svcURL
 			}
 
-			wasmExtensions, err := chain.RegisterSubstreamsExtensions()
-			if err != nil {
-				return nil, fmt.Errorf("substreams extensions: %w", err)
+			var wasmExtensions wasm.WASMExtensioner
+			if chain.RegisterSubstreamsExtensions != nil {
+				exts, err := chain.RegisterSubstreamsExtensions()
+				if err != nil {
+					return nil, fmt.Errorf("substreams extensions: %w", err)
+				}
+				wasmExtensions = exts
 			}
 
 			return app.NewTier2(appLogger,