[Jens-G]

THRIFT-6459

TBufferedTransportImpl.TFactory.GetTransport() created a TFramedTransportImpl, so a server, TSerializer or TDeserializer set up with this factory read and wrote the framed format. It now obtains the transport's IStreamTransport interface with Supports() and creates a TBufferedTransportImpl over it.

A transport without that interface cannot carry a TBufferedTransportImpl, and the factory raises TTransportExceptionBadArgs for it. That includes a transport that is already buffered or framed. Returning such a transport unchanged would be the alternative, if that is preferred.

Everything set up with this factory changes from the framed to the unframed format, so the ticket may want the Breaking-Change label.

Tests, in lib/delphi/test/serializer/TestSerializer.Tests.pas:

• The protocol conformity checks read the plain wire format of each protocol, and they now also run through the buffered transport factory. On master the framed transport takes the first four bytes as a frame length, and the read fails.
• A new Test_TransportFactories checks that each factory returns the transport class it is named for, and that the buffered factory refuses a transport without a stream interface.

Built with Delphi XE (Win32), with no compiler errors, warnings or hints. TestSerializer.dpr in both states:

• master with only this branch's test file: stops at the first buffered factory pair with TTransportExceptionNotOpen: Cannot read, Remote side has closed, because the framed transport takes the first four bytes as a frame length;
• this branch: all factory pairs pass, and so do Test_TransportFactories, Test_COM_Types, Test_ThriftBytesCTORs and Test_Equal.

In a throwaway build that skipped the serializer round trips, Test_TransportFactories alone also failed on master, at the check of the class the buffered factory returns.

• Apache Jira ticket: THRIFT-6459
• Single commit
• Code change, so the commit carries no CI-skip marker.

🤖 Generated with Claude Code