Fix panics by disallowing explicitly-defined null modules in config

Matthew Holt committed Jun 26, 2019 at 10:45 UTC 6000855c82fc1bdc5c256480b4161511f91ed703

1 file changed +9

context.go

@@ -100,6 +100,15 @@ func (ctx Context) LoadModule(name string, rawMsg json.RawMessage) (interface{},

100 }

101 }

102

103 + if val == nil {

104 + // returned module values are almost always type-asserted

105 + // before being used, so a nil value would panic; and there

106 + // is no good reason to explicitly declare null modules in

107 + // a config; it might be because the user is trying to

108 + // achieve a result they aren't expecting, which is a smell

109 + return nil, fmt.Errorf("module value cannot be null")

110 + }

111 +

112 if prov, ok := val.(Provisioner); ok {

113 err := prov.Provision(ctx)

114 if err != nil {