Validate tag omitempty, only base on field value

[nigelis]

Fixes validation of tag omitempty, base on the field value #654.

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• Tests exist or have been written that cover this particular change.

Change Details:

• Validate the tag omitempty, only base on the field value.

@go-playground/admins

[nigelis]

Hi @deankarn ,

Let me explain more about the change.
There are two code blocks in the function traverseField that validates the tag omitempty.

The first code block deals with the situation that the field value is empty and omitempty is the first tag.
When the field value is a nil pointer, the kind would be reflect.Ptr, and no more validation would be continued.

validator/validator.go

Lines 100 to 111 in ea924ce

	current, kind, v.fldIsPointer = v.extractTypeInternal(current, false)
	switch kind {
	case reflect.Ptr, reflect.Interface, reflect.Invalid:
	if ct == nil {
	return
	}
	if ct.typeof == typeOmitEmpty || ct.typeof == typeIsDefault {
	return
	}

The second code block deals with other situations.
When the field value is a pointer, no matter its value, the validation is continued, which is not expected.
Because the hasValue can return the correct value, I simply remove the check about fldIsPointer.

validator/validator.go

Lines 237 to 257 in ea924ce

	for {
	if ct == nil {
	return
	}
	switch ct.typeof {
	case typeOmitEmpty:
	// set Field Level fields
	v.slflParent = parent
	v.flField = current
	v.cf = cf
	v.ct = ct
	if !v.fldIsPointer && !hasValue(v) {
	return
	}
	ct = ct.next
	continue

All previous test cases are passed.
The added test case leads to panic in the v10.3.0, but are passed in the PR.

[frederikhors]

This is still a problem. Is this released in v10? https://play.golang.org/p/TOBSAdFl-FC