fix: Cannot create WorkflowTemplate with un-supplied inputs

workflow/validate/validate.go

@@ -39,6 +39,9 @@ type ValidateOpts struct {
 	// IgnoreEntrypoint indicates to skip/ignore the EntryPoint validation on workflow spec.
 	// Entrypoint is optional for WorkflowTemplate and ClusterWorkflowTemplate
 	IgnoreEntrypoint bool
+
+	// WorkflowTemplateValidation indicates that the current context is validating a WorkflowTemplate or ClusterWorkflowTemplate
+	WorkflowTemplateValidation bool
 }
 
 // templateValidationCtx is the context for validating a workflow spec
@@ -172,7 +175,13 @@ func ValidateWorkflow(wftmplGetter templateresolution.WorkflowTemplateNamespaced
 	}
 
 	if !opts.IgnoreEntrypoint {
-		_, err = ctx.validateTemplateHolder(&wfv1.WorkflowStep{Template: wf.Spec.Entrypoint}, tmplCtx, &wf.Spec.Arguments, map[string]interface{}{})
+		var args wfv1.ArgumentsProvider
+		args = &wf.Spec.Arguments
+
+		if opts.WorkflowTemplateValidation {
+			args = &FakeArguments{}
+		}
+		_, err = ctx.validateTemplateHolder(&wfv1.WorkflowStep{Template: wf.Spec.Entrypoint}, tmplCtx, args, map[string]interface{}{})
 		if err != nil {
 			return nil, err
 		}
@@ -208,13 +217,13 @@ func ValidateWorkflow(wftmplGetter templateresolution.WorkflowTemplateNamespaced
 // ValidateWorkflowTemplate accepts a workflow template and performs validation against it.
 func ValidateWorkflowTemplate(wftmplGetter templateresolution.WorkflowTemplateNamespacedGetter, cwftmplGetter templateresolution.ClusterWorkflowTemplateGetter, wftmpl *wfv1.WorkflowTemplate) (*wfv1.WorkflowConditions, error) {
 	wf := common.ConvertWorkflowTemplateToWorkflow(wftmpl)
-	return ValidateWorkflow(wftmplGetter, cwftmplGetter, wf, ValidateOpts{IgnoreEntrypoint: wf.Spec.Entrypoint == ""})
+	return ValidateWorkflow(wftmplGetter, cwftmplGetter, wf, ValidateOpts{IgnoreEntrypoint: wf.Spec.Entrypoint == "", WorkflowTemplateValidation: true})
 }
 
 // ValidateClusterWorkflowTemplate accepts a cluster workflow template and performs validation against it.
 func ValidateClusterWorkflowTemplate(wftmplGetter templateresolution.WorkflowTemplateNamespacedGetter, cwftmplGetter templateresolution.ClusterWorkflowTemplateGetter, cwftmpl *wfv1.ClusterWorkflowTemplate) (*wfv1.WorkflowConditions, error) {
 	wf := common.ConvertClusterWorkflowTemplateToWorkflow(cwftmpl)
-	return ValidateWorkflow(wftmplGetter, cwftmplGetter, wf, ValidateOpts{IgnoreEntrypoint: wf.Spec.Entrypoint == ""})
+	return ValidateWorkflow(wftmplGetter, cwftmplGetter, wf, ValidateOpts{IgnoreEntrypoint: wf.Spec.Entrypoint == "", WorkflowTemplateValidation: true})
 }
 
 // ValidateCronWorkflow validates a CronWorkflow

workflow/validate/validate_test.go

@@ -2385,3 +2385,26 @@ func TestWorfklowGlobalVariables(t *testing.T) {
 	_, err := validate(globalVariables)
 	assert.NoError(t, err)
 }
+
+var wfTemplateWithEntrypoint = `
+apiVersion: argoproj.io/v1alpha1
+kind: WorkflowTemplate
+metadata:
+  name: template-with-entrypoint
+spec:
+  entrypoint: whalesay-template
+  templates:
+  - name: whalesay-template
+    inputs:
+      parameters:
+      - name: message
+    container:
+      image: docker/whalesay
+      command: [cowsay]
+      args: ["{{inputs.parameters.message}}"]
+`
+
+func TestWorkflowTemplateWithEntrypoint(t *testing.T) {
+	err := validateWorkflowTemplate(wfTemplateWithEntrypoint)
+	assert.NoError(t, err)
+}