diff --git a/context.go b/context.go
index b077623..4794934 100644
--- a/context.go
+++ b/context.go
@@ -2429,6 +2429,10 @@
 	buf := bytes.NewBuffer(nil)
 
 	for _, module := range modules {
+		if len(module.actionDefs.variables)+len(module.actionDefs.rules)+len(module.actionDefs.buildDefs) == 0 {
+			continue
+		}
+
 		buf.Reset()
 
 		// In order to make the bootstrap build manifest independent of the
@@ -2497,6 +2501,10 @@
 	for _, name := range singletonNames {
 		info := c.singletonInfo[name]
 
+		if len(info.actionDefs.variables)+len(info.actionDefs.rules)+len(info.actionDefs.buildDefs) == 0 {
+			continue
+		}
+
 		// Get the name of the factory function for the module.
 		factory := info.factory
 		factoryFunc := runtime.FuncForPC(reflect.ValueOf(factory).Pointer())