mapEntry

Whether the message is an automatically generated map entry type for the maps field.

For maps fields: map map_field = 1; The parsed descriptor looks like: message MapFieldEntry { option map_entry = true; optional KeyType key = 1; optional ValueType value = 2; } repeated MapFieldEntry map_field = 1;

Implementations may choose not to generate the map_entry=true message, but use a native map in the target language to hold the keys and values. The reflection APIs in such implementations still need to work as if the field is a repeated message field.

NOTE: Do not set the option in .proto files. Always use the maps syntax instead. The option should only be implicitly set by the proto compiler parser.