Remove repeated extension fields from the set of nullable fields,
so that Has reports false and Range does not visit a a zero-length
repeated extension field.
This corrects a fuzzer-detected case where unmarshaling and remarshaling
a wire-format message could result in a semantic change. For a repeated
extension field in non-packed encoding, unmarshaling a packed
representation of the field would result in a message which Has the
extension. Remarshaling it would discard the the field.
Fixesgolang.org/protobuf#975
Change-Id: Ie836559c93d218db5b5201742a3b8ebbaacf54ed
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/204897
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Joe Tsai <joetsai@google.com>
Test the fuzzer with a minimal seed corpus. (Currently one file
containing a valid TestAllTypes messge with most fields set.)
Change-Id: I8dcec4e26f1e8374993cc3a4bef0496f36cccd41
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/201639
Reviewed-by: Herbie Ong <herbie@google.com>
