Add nostructlevel tag

* nostructlevel - Same as structonly tag except that any struct level
		  validations will not run.

Author: joeybloggs

doc.go

@@ -138,6 +138,9 @@ Here is a list of the current built in validators:
 		you know the struct will be valid, but need to verify it has been assigned.
 		NOTE: only "required" and "omitempty" can be used on a struct itself.
 
+	nostructlevel
+		Same as structonly tag except that any struct level validations will not run.
+
 	exists
 		Is a special tag without a validation function attached. It is used when a field
 		is a Pointer, Interface or Invalid and you wish to validate that it exists.

util.go

@@ -26,6 +26,7 @@ var (
 		skipValidationTag: emptyStructPtr,
 		utf8HexComma:      emptyStructPtr,
 		utf8Pipe:          emptyStructPtr,
+		noStructLevelTag:  emptyStructPtr,
 	}
 )
 

validator.go

@@ -26,6 +26,7 @@ const (
 	orSeparator             = "|"
 	tagKeySeparator         = "="
 	structOnlyTag           = "structonly"
+	noStructLevelTag        = "nostructlevel"
 	omitempty               = "omitempty"
 	skipValidationTag       = "-"
 	diveTag                 = "dive"
@@ -595,6 +596,11 @@ func (v *Validate) traverseField(topStruct reflect.Value, currentStruct reflect.
 		typ = current.Type()
 
 		if typ != timeType {
+
+			if strings.Contains(tag, noStructLevelTag) {
+				return
+			}
+
 			v.tranverseStruct(topStruct, current, current, errPrefix+name+".", errs, false, partial, exclude, includeExclude, strings.Contains(tag, structOnlyTag))
 			return
 		}

validator_test.go

@@ -3493,6 +3493,36 @@ func TestBase64Validation(t *testing.T) {
 	AssertError(t, errs, "", "", "base64")
 }
 
+func TestNoStructLevelValidation(t *testing.T) {
+
+	type Inner struct {
+		Test string `validate:"len=5"`
+	}
+
+	type Outer struct {
+		InnerStruct *Inner `validate:"required,nostructlevel"`
+	}
+
+	outer := &Outer{
+		InnerStruct: nil,
+	}
+
+	errs := validate.Struct(outer)
+	NotEqual(t, errs, nil)
+	AssertError(t, errs, "Outer.InnerStruct", "InnerStruct", "required")
+
+	inner := &Inner{
+		Test: "1234",
+	}
+
+	outer = &Outer{
+		InnerStruct: inner,
+	}
+
+	errs = validate.Struct(outer)
+	Equal(t, errs, nil)
+}
+
 func TestStructOnlyValidation(t *testing.T) {
 
 	type Inner struct {
@@ -3509,6 +3539,7 @@ func TestStructOnlyValidation(t *testing.T) {
 
 	errs := validate.Struct(outer)
 	NotEqual(t, errs, nil)
+	AssertError(t, errs, "Outer.InnerStruct", "InnerStruct", "required")
 
 	inner := &Inner{
 		Test: "1234",