makefmt

Fast, safe Makefile and justfile formatter. Aligns assignments and line continuations and indents conditional blocks.

CC=gcc
CFLAGS   :=-O2 -Wall

ifeq ($(DEBUG),1)
CFLAGS += -g
endif

all:main.o   util.o
	$(CC) $(CFLAGS) -o app $^

becomes

CC     = gcc
CFLAGS := -O2 -Wall

ifeq ($(DEBUG),1)
  CFLAGS += -g
endif

all: main.o util.o
	$(CC) $(CFLAGS) -o app $^

makefmt never changes what make does. Recipe lines and define bodies are left exactly as written.

Justfiles get the same output as just --fmt, without needing just installed.

The formatter is written in Rust and runs inside VS Code as WebAssembly, so formatting is instant and works on vscode.dev too.

Usage

makefmt becomes the default formatter for Makefiles and justfiles once installed. Files named justfile, Justfile, .justfile or *.just are recognized as justfiles. Run Format Document (Shift+Alt+F), or format on save:

{
  "[makefile]": {
    "editor.formatOnSave": true
  },
  "[just]": {
    "editor.formatOnSave": true
  }
}

Settings

Project config

A .makefmt.toml in the Makefile's folder or any parent folder takes precedence over the settings above, so everyone on the project gets the same output:

align_assignments = true
align_continuations = true
indent_conditionals = true
indent_width = 4

Missing keys use the defaults. Unknown keys are an error. The settings and the file only apply to Makefiles; justfiles always use the style of just --fmt.

CLI

The same formatter is available on npm as makefmt for CI and pre-commit hooks:

npx makefmt --check .