fix: value is required when parameter is of type enum (#9753)

* fix: `value` is required when parameter is of type
`enum`

Without this change we get error:
`Recovered from panic: runtime error: invalid memory address or nil pointer dereference`

Signed-off-by: Ricardo Rosales <728243+missingcharacter@users.noreply.github.com>

* fix: Adding test TestWorkflowTemplateWithEnumValueWithoutValue

Signed-off-by: Ricardo Rosales <728243+missingcharacter@users.noreply.github.com>

Signed-off-by: Ricardo Rosales <728243+missingcharacter@users.noreply.github.com>

workflow/validate/validate.go

@@ -764,6 +764,9 @@ func validateArgumentsValues(prefix string, arguments wfv1.Arguments, allowEmpty
 			if len(param.Enum) == 0 {
 				return errors.Errorf(errors.CodeBadRequest, "%s%s.enum should contain at least one value", prefix, param.Name)
 			}
+			if param.Value == nil {
+				return errors.Errorf(errors.CodeBadRequest, "%s%s.value is required", prefix, param.Name)
+			}
 			valueSpecifiedInEnumList := false
 			for _, enum := range param.Enum {
 				if enum == *param.Value {

workflow/validate/validate_test.go

@@ -2494,6 +2494,38 @@ spec:
           - '{{inputs.parameters.message}}'
 `
 
+var workflowTeamplateWithEnumValuesWithoutValue = `
+apiVersion: argoproj.io/v1alpha1
+kind: WorkflowTemplate
+metadata:
+  generateName: test-enum-1-
+  labels:
+    testLabel: foobar
+spec:
+  entrypoint: argosay
+  arguments:
+    parameters:
+      - name: message
+        enum:
+            - one
+            - two
+            - three
+  templates:
+    - name: argosay
+      inputs:
+        parameters:
+          - name: message
+            value: '{{workflow.parameters.message}}'
+      container:
+        name: main
+        image: 'argoproj/argosay:v2'
+        command:
+          - /argosay
+        args:
+          - echo
+          - '{{inputs.parameters.message}}'
+`
+
 func TestWorkflowTemplateWithEnumValue(t *testing.T) {
 	err := validateWorkflowTemplate(workflowTeamplateWithEnumValues, ValidateOpts{})
 	assert.NoError(t, err)
@@ -2521,6 +2553,15 @@ func TestWorkflowTemplateWithArgumentValueNotFromEnumList(t *testing.T) {
 	assert.EqualError(t, err, "spec.arguments.message.value should be present in spec.arguments.message.enum list")
 }
 
+func TestWorkflowTemplateWithEnumValueWithoutValue(t *testing.T) {
+	err := validateWorkflowTemplate(workflowTeamplateWithEnumValuesWithoutValue, ValidateOpts{})
+	assert.EqualError(t, err, "spec.arguments.message.value is required")
+	err = validateWorkflowTemplate(workflowTeamplateWithEnumValuesWithoutValue, ValidateOpts{Lint: true})
+	assert.EqualError(t, err, "spec.arguments.message.value is required")
+	err = validateWorkflowTemplate(workflowTeamplateWithEnumValuesWithoutValue, ValidateOpts{Submit: true})
+	assert.EqualError(t, err, "spec.arguments.message.value is required")
+}
+
 var validActiveDeadlineSecondsArgoVariable = `
 apiVersion: argoproj.io/v1alpha1
 kind: Workflow