Even though gRPC provides some leeway, as "Access to metadata is
language dependent", we have yet to see an implementation which doesn't
support multiple values per key.
Common implementations like grpc-c++, grpc-go or grpc-java provide this
and we should do it aswell.
Ref: https://grpc.io/docs/what-is-grpc/core-concepts/#metadata
Ref: https://github.com/grpc/grpc-go/blob/master/Documentation/grpc-metadata.md#constructing-metadata
Use a base class to implement common functionality for the options
classes. Also use a new common class in the tests.
The QMultiHash overload is selected when the 'QtGrpc::MultiValue'
argument is used in 'metadata' calls. We update the documentation
accordingly.
Deprecation is scheduled for Qt 6.13
Users with a custom Qt build - those who care - should be rewarded with
minimal traces of this "accident" and should not suffer from potential
performance/storage overhead. Therefore we deprecate QtGrpc::MultiValue
for those builds, effectively providing Qt 7 behavior.
[ChangeLog][Deprecation Notice]
Deprecate the metadata()/setMetadata() methods on QGrpcCallOptions and
QGrpcChannelOptions that use QHash in favor of the new overloads that
use QMultiHash. This is more in line with the gRPC specification.
Fixes: QTBUG-136471
Change-Id: I58d14d2c304c06de269c99ba5383beee86d12f77
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Dennis Oberst