HaveField: cannot call method with pointer receiver for values

[pohly]

I recently suggested replacing these checks with ConsistOf + HaveField("GetName()", Equal:

	gomega.Expect(len(list.Items)).To(gomega.BeIdenticalTo(2))
	framework.ExpectEqual((list.Items[0].GetName() == name1 && list.Items[1].GetName() == name2) ||
		(list.Items[0].GetName() == name2 && list.Items[1].GetName() == name1), true)

=>

gomega.Expect(list.Items).To(gomega.ConsistOf(gomega.HaveField("GetName()", gomega.Equal(name1)), gomega.HaveField("GetName()", gomega.Equal(name2))))

That didn't work. It turned out that the slice elements are values and their GetName method is only defined for pointers. Go can call it anyway, but Gomega can't (or doesn't). Perhaps it should also support that?

Here's a reproducer:

package gomegatest

import (
	"testing"

	"github.com/onsi/gomega"
)

type pointerobject struct {
	name string
}

func (p *pointerobject) GetName() string {
	return p.name
}

type valueobject struct {
	name string
}

func (v valueobject) GetName() string {
	return v.name
}

type object interface {
	GetName() string
}

var _ object = valueobject{}

// Only pointer implements object interface, not value.
var _ object = &pointerobject{}

// var _ object = pointerobject{}

func TestConsistsOf(t *testing.T) {
	g := gomega.NewGomegaWithT(t)
	e := gomega.ConsistOf(gomega.HaveField("GetName()", gomega.Equal("A")), gomega.HaveField("GetName()", gomega.Equal("B")))

	g.Expect([]valueobject{{"A"}, {"B"}}).To(e)   // works
	g.Expect([]pointerobject{{"A"}, {"B"}}).To(e) // fails
}

[thediveo]

looking into the matcher code base that was originally deliberate; if there is no reason why we should keep this restriction then there's a PR. Yeah, I've just run into this myself 😀