tree bf1864a79c1204b2003b5afe9377e8d34464e4f1
parent a4cbffe4bcbad833cba75e6e16223b2c7c88b48a
author Joe Tsai <joetsai@digital-static.net> 1544127041 -0800
committer Joe Tsai <thebrokentoaster@gmail.com> 1544211749 +0000

reflect/protoreflect: add MessageDescriptor.ExtensionRangeOptions

Considerable thought was given to whether a seperate ExtensionRanges interface
should be made that encapsulates FieldNumbers with an Options method.
However, I decided against this design for the following reasons:
* Extension ranges share syntax with reserved numbers and fields.
Why is extension ranges so special that it can have options, while the other
two currently do not? How do we know that those other two won't grow options
in the future? If they do, then those APIs can be expanded in the same way as
how extension range options is being expanded here today.
* Extension range options stand out like a sore thumb compared to the other
eight options. The other options correspond with a named declaration and have
a full protobuf name that they are associated with. Extension range options
is the only options that is not correlated with a full name.
* Extension range options are an extremely rarely used feature and
it seems unfortunate complicating the common case with additional structure.

Change-Id: Ib284a0b798c57dc264febe304692eee5b9c8e91b
Reviewed-on: https://go-review.googlesource.com/c/153018
Reviewed-by: Damien Neil <dneil@google.com>