# oneof-naming

Source: https://apigenie.pl/docs/linter/protobuf/rules/oneof-naming

This rule checks whether the name of every oneof of a Protobuf file is in `lower_snake_case`.

## Rule Details

Code generators derive the names of the accessors and case enums of oneofs from their Protobuf
names, assuming `lower_snake_case`, like for fields.

The `oneof-naming` rule checks every oneof, and reports `Oneof name '<name>' should be
lower_snake_case` for every name that is not in `lower_snake_case`. A name is in
`lower_snake_case` when it starts with a lower-case letter and contains only lower-case letters,
digits and single underscores, with no underscore at the end, such as `owner_name` or
`address_2`.

When the name converted to `lower_snake_case` differs from the original and is itself valid, the
message ends with a suggestion, for example `, e.g. '<converted>'`. To convert a name, it is
split into words at underscores and other separators, at lower-to-upper case changes and before
the last capital of an acronym, and the words are joined in lower case with underscores, so
`ownerName` becomes `owner_name` and `HTTPServer` becomes `http_server`.

## Configuration

This rule has no options.

## Examples

**Good**.

```proto
syntax = "proto3";

package acme.pets.v1;

message Pet {
  string name = 1;
  oneof owner_contact {
    string email = 2;
    string phone = 3;
  }
}
```

**Bad**. The linter reports `Oneof name 'ownerContact' should be lower_snake_case, e.g. 'owner_contact'`.

```proto
syntax = "proto3";

package acme.pets.v1;

message Pet {
  string name = 1;
  oneof ownerContact {
    string email = 2;
    string phone = 3;
  }
}
```

## When Not to Use It

You may disable this rule if the names are part of an existing API that you cannot rename. To
allow a single oneof, add an `// apigenie-lint-disable oneof-naming` comment to it.

## Compatibility

This rule is compatible with proto3 files. proto2 and editions files are rejected by the reader
and are not linted.