hk util format-diff

• How to hail it: hk util format-diff [--no-stdin] <FILES>… <-- COMMAND>…

Prints a patch of what a sailmaker (formatter) would change, for a check_diff command.

Runs COMMAND once for each file, with the file on stdin, and compares what it prints with the file. {} in COMMAND is replaced with the file's path, for formatters that take the path of their input as an option. With --no-stdin, COMMAND reads the file itself, from the path {} gives it. Files are formatted in parallel: all hands haul at once.

Prints a unified diff for every file that would change and exits 1, or exits 0 when none would. If COMMAND fails for any file, or prints nothing for a file that isn't empty, no patch is printed at all: its error output is shown, and hk runs the step's fixer instead to mend the canvas.

For example: hk util format-diff a.lua b.lua -- stylua --stdin-filepath {} -

Cargo it takes

• <FILES>… — The files to format
• <-- COMMAND>… — The sailmaker (formatter), reading stdin and writing the formatted file to stdout

Flags to fly

• --no-stdin — Give COMMAND no stdin, for a formatter that reads the file at {} itself
• -h --help — Print help, for when ye've lost yer bearings

Further charts

Built-in linters and utilities: the standing crew · Troubleshooting: the ship's log · All the bosun's calls