Black vs gofmt

Black is a free, MIT-licensed formatter for Python code that follows PEP 8. It reformats whole files in place and uses a default line length of 88 characters. Its limited style choices are intended to keep code consistent across projects; indentation style cannot be configured. After formatting, Black checks whether the abstract syntax tree remains effectively equivalent and raises an error if the check fails. Install it with pip; it requires Python 3.10 or newer. The documentation lists editor integrations including Emacs, PyCharm, IntelliJ IDEA, Vim, Neovim, Visual Studio Code and Sublime Text, as well as GitHub Actions and doctest workflows. Notebook formatting is available with the jupyter extra, though Black skips cells containing certain magics or invalid syntax. It also includes blackd, an HTTP server that binds to localhost by default. Black is primarily a command-line tool and does not provide a Python interface. Stable releases preserve formatting within the same calendar year when the options match.

gofmt is the Go source formatter distributed with Go installations, available on Linux, macOS, and Windows. It formats Go programs using tabs for indentation and spaces for alignment. With no path, it reads standard input; given a directory, it processes .go files recursively while skipping files whose names begin with a period. By default, reformatted source is written to standard output. Flags can show differences, list files that need formatting, apply rewrite rules, simplify code, or report all errors. The rewrite option uses patterns and replacements written as valid Go expressions. gofmt can also arrange documentation comments into canonical paragraphs, lists, headings, links, and code blocks. The Go project documents integrations for Vim, Emacs, Eclipse, and Sublime Text, plus Git pre-commit hooks and Mercurial. Since Go 1.18, it reads and formats files concurrently, with memory use limited in proportion to GOMAXPROCS. The executable is equivalent to go fmt. It is free, included in the Go installation, and distributed under a BSD-style license.