Fix #7998: ignore event fields that contains a nil interface of type encoding.TextMarshaler

[cyrilleverrier]

Fix #7998: ignore event fields that contains a nil interface of type encoding.TextMarshaler

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[kvch]

jenkins test this

[andrewkroh]

Does it make sense to do this check up on line 135 where we check for plain old nil?

[cyrilleverrier]

Value may be either a nil interface of an interface storing a nil pointer :)

when running the libbeat TestNormalizeValue unit tests:

1. the check for value == nil at line 135 protects against the test {nil, nil}
2. the check for stored nil pointers that I added at line 161 protects against {nilTimePtr, nil}

[andrewkroh]

Right, but should we do this check immediately upon entering normalizeValue so that we drop all interfaces storing nil pointers?

[cyrilleverrier]

@andrewkroh: I didn't want to add a run-time check for all fields in the event map.

The 2 cases where the interface{} can store a pointer to a nil value are encoding.TextMarshaler and followPointer. And followPointer already checks for nil pointer

If you prefer, I can move the test to the beginning of the function normalizeValue.
It could be safer if a new encoder case is added later.

[andrewkroh]

I didn't want to add a run-time check for all fields in the event map.

I suspected that might be a reason for not doing it at method entry.

[andrewkroh]

jenkins test this