Regression: unregistering "builtin" collectors stopped working with 1.2.0

[costela]

This simple test case showcases the problem:

func TestRegisterUnregisterCollector(t *testing.T) {
	col := prometheus.NewGoCollector()

	reg := prometheus.NewRegistry()
	reg.MustRegister(col)
	reg.Unregister(col)
	if metrics, err := reg.Gather(); err != nil {
		t.Error("error gathering sample metric")
	} else if len(metrics) != 0 {
		t.Error("should have unregistered metric")
	}
}

This passed up to v1.1.0, but fails on v1.2.0 (and master).

The calculation of collectorID got changed in 1.2.0 and the same change was not applied to unregistering. PR follows shortly.

[beorn7]

Ouch. Thanks for spotting.

Perils of code duplication. But with #663, there will be a test.

[costela]

Happy to help! :)

[beorn7]

v1.2.1 coming.