fix(validate): Fix DAG validation on task names when depends/dependen…

…cies is not used. Fixes #5993 (#5998)

Signed-off-by: terrytangyuan <[email protected]>

workflow/validate/validate.go

@@ -1157,7 +1157,7 @@ func (ctx *templateValidationCtx) validateDAG(scope map[string]interface{}, tmpl
 	// Verify dependencies for all tasks can be resolved as well as template names
 	for _, task := range tmpl.DAG.Tasks {
 
-		if '0' <= task.Name[0] && task.Name[0] <= '9' {
+		if (usingDepends || len(task.Dependencies) > 0) && '0' <= task.Name[0] && task.Name[0] <= '9' {
 			return errors.Errorf(errors.CodeBadRequest, "templates.%s.tasks.%s name cannot begin with a digit when using either 'depends' or 'dependencies'", tmpl.Name, task.Name)
 		}
 

workflow/validate/validate_dag_test.go

@@ -893,3 +893,32 @@ func TestDAGDependenciesDigit(t *testing.T) {
 		assert.Contains(t, err.Error(), "templates.diamond.tasks.5A name cannot begin with a digit when using either 'depends' or 'dependencies'")
 	}
 }
+
+var dagWithDigitNoDepends = `
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  generateName: dag-diamond-
+spec:
+  entrypoint: diamond
+  templates:
+    - name: diamond
+      dag:
+        tasks:
+          - name: 5A
+            template: pass
+          - name: B
+            template: pass
+    - name: pass
+      container:
+        image: alpine:3.7
+        command:
+          - sh
+          - -c
+          - exit 0
+`
+
+func TestDAGWithDigitNameNoDepends(t *testing.T) {
+	_, err := validate(dagWithDigitNoDepends)
+	assert.NoError(t, err)
+}