# enum-value-naming

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

This rule checks whether the name of every enum value of a Protobuf file is in
`UPPER_SNAKE_CASE`.

## Rule Details

Enum values are constants, and `UPPER_SNAKE_CASE` is how most target languages write constants.
It is also what the Protobuf style guide recommends.

The `enum-value-naming` rule checks every enum value, and reports `Enum value name '<name>'
should be UPPER_SNAKE_CASE` for every name that is not in `UPPER_SNAKE_CASE`. A name is in
`UPPER_SNAKE_CASE` when it starts with an upper-case letter and contains only upper-case
letters, digits and single underscores, with no underscore at the end, such as `PET_KIND_DOG`.

When the name converted to `UPPER_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 upper case with underscores, so
`petKindDog` becomes `PET_KIND_DOG`.

## Configuration

This rule has no options.

## Examples

**Good**.

```proto
syntax = "proto3";

package acme.pets.v1;

enum PetKind {
  PET_KIND_UNSPECIFIED = 0;
  PET_KIND_DOG = 1;
}
```

**Bad**. The linter reports `Enum value name 'petKindDog' should be UPPER_SNAKE_CASE, e.g. 'PET_KIND_DOG'`.

```proto
syntax = "proto3";

package acme.pets.v1;

enum PetKind {
  PET_KIND_UNSPECIFIED = 0;
  petKindDog = 1;
}
```

## 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 enum value, add an `// apigenie-lint-disable enum-value-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.