tree 2542582455b9da5edba985567619ea729eb01c72
parent 82886da2b9aa8030165f94a931e2ed0000aa0809
author Damien Neil <dneil@google.com> 1574803898 -0800
committer Damien Neil <dneil@google.com> 1574809131 +0000

all: fix reflection behavior for empty lists and maps

The protoreflect documentation states that Get on an empty repeated or
map field returns an invalid (empty, read-only) List or Map. We weren't
doing this; fix it.

The documentation also states that an invalid List or Map may not be
assigned via Set. We were permitting Set with an invalid map; fix this.

Add tests for this behavior in prototest.

Change-Id: I4678af532e192210af0bde7c96a1439a4cd26efa
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/209019
Reviewed-by: Joe Tsai <joetsai@google.com>