readability-trailing-comma

Checks for presence or absence of trailing commas in enum definitions and initializer lists.

The check supports separate policies for single-line and multi-line constructs, allowing different styles for each. By default, the check enforces trailing commas in multi-line constructs and removes them from single-line constructs.

Trailing commas in multi-line constructs offer several benefits:

• Adding or removing elements at the end only changes a single line, making diffs smaller and easier to read.

• Formatters may change code to a more desired style.

• Code generators avoid the need for special handling of the last element.

// Without trailing commas - adding "Yellow" requires modifying the "Blue" line
enum Color {
  Red,
  Green,
  Blue
};

// With trailing commas - adding "Yellow" is a clean, single-line change
enum Color {
  Red,
  Green,
  Blue,
};

Limitations

The check currently doesn’t analyze code inside macros.

Options

SingleLineCommaPolicy

Controls whether to add, remove, or ignore trailing commas in single-line enum definitions and initializer lists. Valid values are:

• Append: Add trailing commas where missing.

• Remove: Remove trailing commas where present.

• Ignore: Do not check single-line constructs.

Default is Remove.

MultiLineCommaPolicy

Controls whether to add, remove, or ignore trailing commas in multi-line enum definitions and initializer lists. Valid values are:

• Append: Add trailing commas where missing.

• Remove: Remove trailing commas where present.

• Ignore: Do not check multi-line constructs.

Default is Append.