Upgrading to 2.0

Version 2.0 introduces breaking Rust API changes, preserves original argument comment placement by default, and adds a dprint WebAssembly plugin. CLI flag names, configuration-file syntax, and the LSP interface remain unchanged.

Building the next release from source

The current source checkout and next release require Rust 1.89 or later. The YAML backend has moved to serde-saphyr, removing the unmaintained libyaml dependency. Existing configuration options and CLI flags are unchanged; YAML aliases and merge keys remain supported. Generated YAML may use different quoting or indentation, but can still be loaded as configuration.

Prebuilt binaries, Python wheels, and editor integrations do not require a local Rust toolchain. The Rust 1.88 requirement below applies to the 2.0 and 2.1 releases.

Rust library consumers

Update the cmakefmt-rust dependency requirement to major version 2 when the release is available. Source builds require Rust 1.88 or later.

The parser now distinguishes comments on their own lines (Argument::StandaloneComment) from comments following an argument on the same line (Argument::InlineComment). Argument is non-exhaustive: include a fallback arm when matching it. Do not silently treat unknown variants as comments or ordinary tokens when semantic correctness depends on the variant.

use cmakefmt::parser::ast::Argument;

fn describe(argument: &Argument) -> &'static str {
    match argument {
        Argument::StandaloneComment(_) => "standalone comment",
        Argument::InlineComment(_) => "inline comment",
        Argument::Bracket(_) | Argument::Quoted(_) | Argument::Unquoted(_) => "value",
        _ => "unsupported argument variant",
    }
}

Use argument.is_comment() if you only need to distinguish comments from values, and argument.as_str() to obtain their raw text.

Config has a new argument_comment_style field. Rather than listing every field, use defaults with explicit overrides:

use cmakefmt::{ArgumentCommentStyle, Config};

let config = Config {
    line_width: 100,
    argument_comment_style: ArgumentCommentStyle::Preserve,
    ..Config::default()
};

Config remains an exhaustive struct; this construction pattern avoids listing all fields, but is not a promise that future field additions are source-compatible with complete struct literals.

Formatting and CI

The default format.argument_comment_style: preserve keeps standalone argument comments on their own lines and inline comments attached where they fit. Use standalone to put every argument comment on a separate line:

format:
  argument_comment_style: standalone

Neither setting restores the old behaviour of moving standalone comments onto argument lines. For example, start with this mixture of inline and standalone comments:

set(SOURCES
  main.cpp # entry point
  # platform implementation
  platform.cpp)

With argument_comment_style: preserve (the default), the inline comment stays beside main.cpp, while the standalone comment stays above platform.cpp:

set(SOURCES
    main.cpp # entry point
    # platform implementation
    platform.cpp)

With argument_comment_style: standalone, the inline comment moves onto a new line after the argument it followed. The existing standalone comment stays in place:

set(SOURCES
    main.cpp
    # entry point
    # platform implementation
    platform.cpp)

These examples use the other default formatting settings. In preserve mode, an inline comment can still move to a new line if it does not fit within line_width; preserving placement does not override the line-width limit.

Review the output before updating formatting baselines:

cmakefmt --diff .
cmakefmt --check .

If the changes are appropriate, run cmakefmt -i ., review and commit the diff, then rerun your formatting checks. Correctness fixes may also change affected FetchContent_Declare and add_subdirectory calls.

Prebuilt binaries and Python wheels do not require Rust. Workflows pinning a formatter version need an explicit update; workflows using latest may pick up 2.0 automatically. The GitHub Action’s own version is separate from the formatter’s version: keep the action version you use and set its version input to 2.0.0 after publication if you want an explicit formatter pin.

WebAssembly builds

Browser exports now require an explicit feature:

wasm-pack build --target web --no-default-features --features browser-wasm

The dprint plugin uses dprint-plugin instead. Do not combine the two features when building a WebAssembly artifact; they expose different host protocols. See Editor Integration for dprint configuration.