Re: [protobuf] Upgrading float fields to double

I think the way to do it is just to create a new, separate double field and migrate over to that new field. Depending on how your message is used, you might have to temporarily populate both fields until all readers have been updated to prefer the new field. On Thu, Nov 16, 2017 at 1:35 PM, James

Re: [protobuf] Upgrading float fields to double

OK, thanks. Is there a recommended way of upgrading a float field to a double field? There is no discussion of this path right now in the protobuf docs. James On Thursday, November 16, 2017 at 11:16:58 AM UTC-8, liujisi wrote: > > The spec doesn't allow such conversion. If some language

Re: [protobuf] Upgrading float fields to double

The spec doesn't allow such conversion. If some language implementation supports the conversion, it is considered a bug by not following spec. Protobuf is designed to interop across different languages/platforms. Implicit conversion in "some libraries" allows creating non portable payload

Re: [protobuf] Upgrading float fields to double

float is 4 bytes on wire, while double is 8 bytes on wire. If you change float to double, in the case of old data and new parser, the parser will take the additional 4 bytes as double (these additional 4 bytes should belong to the next field in wire), in the case of new data and old parser, the

Re: [protobuf] Upgrading float fields to double

But the type stored on the wire is known - so it seems like it could be supported (simply static_cast(float_val)). By 'some libraries': does the C++ ParseFromString method do this or not? Thanks! James On Wed, Nov 15, 2017 at 3:57 PM Marc Gravell wrote: > Not really,

Re: [protobuf] Upgrading float fields to double

Not really, no. They take different amounts of space on the wire, and have a different declared wire type (header). Some libraries may choose to be gracious and apply the conversion silently, but other libraries could just say "unexpected wire type" and stop processing. You could perhaps do it as

[protobuf] Upgrading float fields to double

Hi, Is it safe to upgrade float fields to doubles for serialized protos? If not, why not? Thanks, James -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To unsubscribe from this group and stop receiving emails from it, send an email to