output warning flag

terraform/eval_output.go

@@ -68,9 +68,9 @@ func (n *EvalWriteOutput) Eval(ctx EvalContext) (interface{}, error) {
 
 	// handling the interpolation error
 	if err != nil {
-		if n.ContinueOnErr {
+		if n.ContinueOnErr || flagWarnOutputErrors {
 			log.Printf("[ERROR] Output interpolation %q failed: %s", n.Name, err)
-			// if we're continueing, make sure the output is included, and
+			// if we're continuing, make sure the output is included, and
 			// marked as unknown
 			mod.Outputs[n.Name] = &OutputState{
 				Type:  "string",

terraform/features.go

@@ -1,3 +1,7 @@
 package terraform
 
+import "os"
+
 // This file holds feature flags for the next release
+
+var flagWarnOutputErrors = os.Getenv("TF_WARN_OUTPUT_ERRORS") != ""