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Document field number limits, including for MessageSet extensions. - #337
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Regular field numbers are limited to 2^29 - 1 because they share a tag with the wire type, but MessageSet extension numbers are encoded as a separate varint, so they are instead limited by the descriptor representation: the largest number an extension range can contain is 2^31 - 2. Add a Field Numbers section to go/proto-limits, and note in the proto2 and editions language guides that `max` is 2^31 - 2 for MessageSet messages. PiperOrigin-RevId: 1002463091
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Document field number limits, including for MessageSet extensions.
Regular field numbers are limited to 2^29 - 1 because they share a tag with
the wire type, but MessageSet extension numbers are encoded as a separate
varint, so they are instead limited by the descriptor representation: the
largest number an extension range can contain is 2^31 - 2. Add a Field Numbers
section to go/proto-limits, and note in the proto2 and editions language guides
that
maxis 2^31 - 2 for MessageSet messages.