bug: swift_format doesn't respect .swift-format file

[heygarrett]

Neovim version (nvim -v)

NVIM v0.9.4

Operating system/version

macOS 14.1.1 (23B81)

Add the debug logs

• I have set log_level = vim.log.levels.DEBUG and pasted the log contents below.

Log file

Log file: /Users/garrett/dev/scrap/conform-swift/.repro//state/nvim/conform.log
          22:37:11[DEBUG] Run command: { "swift-format" }
          22:37:11[DEBUG] swift_format exited with code 0
          22:38:05[DEBUG] Running formatters on /Users/garrett/dev/scrap/conform-swift/Package.swift: { "swift_format" }
          22:38:05[INFO] Run swift_format on /Users/garrett/dev/scrap/conform-swift/Package.swift
          22:38:05[DEBUG] Run command: { "swift-format" }
          22:38:05[DEBUG] swift_format exited with code 0
          22:39:40[DEBUG] Running formatters on /Users/garrett/dev/scrap/conform-swift/Package.swift: { "swift_format" }
          22:39:40[INFO] Run swift_format on /Users/garrett/dev/scrap/conform-swift/Package.swift
          22:39:40[DEBUG] Run command: { "swift-format", "--configuration", ".swift-format" }
          22:39:40[DEBUG] swift_format exited with code 0
          22:40:05[DEBUG] Running formatters on /Users/garrett/dev/scrap/conform-swift/Package.swift: { "swift_format" }
          22:40:05[INFO] Run swift_format on /Users/garrett/dev/scrap/conform-swift/Package.swift
          22:40:05[DEBUG] Run command: { "swift-format" }
          22:40:05[DEBUG] swift_format exited with code 0

Formatters for this buffer:
swift_format ready (swift)

Other formatters:

Describe the bug

When using the configuration of swift-format included in conform.nvim (listed as swift_format), the presence of a .swift-format file is not respected when formatting Swift code. Running swift-format from the command line does respect the .swift-format file by default.

Adding prepend_args = { "--configuration", ".swift-format" } to the swift_format configuration does resolve the issue, but doesn't explain why the configuration file isn't respected by default.

Steps To Reproduce

1. mkdir conform-swift && cd conform-swift
2. swift package init --type executable
3. echo '{ "indentation": { "tabs": 1 } }' > .swift-format
4. nvim -u repro.lua Package.swift
5. :lua require("conform").format()
6. Uncomment the line in repro.lua that adds the prepend_args property
7. Repeat steps 4 and 5

Expected Behavior

The spaces used for indentation in the Package.swift file would be replaced with tabs, as configured in the .swift-format file.

It only works after adding the prepend_args property as detailed above.

Minimal example file

swift package init --type executable will create the Package.swift file I'm using to reproduce the issue, but I'll include it here also:

// swift-tools-version: 5.9
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "conform-swift",
    targets: [
        // Targets are the basic building blocks of a package, defining a module or a test suite.
        // Targets can depend on other targets in this package and products from dependencies.
        .executableTarget(
            name: "conform-swift")
    ]
)

Minimal init.lua

-- DO NOT change the paths and don't remove the colorscheme
local root = vim.fn.fnamemodify("./.repro", ":p")

-- set stdpaths to use .repro
for _, name in ipairs({ "config", "data", "state", "cache" }) do
	vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. "/" .. name
end

-- bootstrap lazy
local lazypath = root .. "/plugins/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
	vim.fn.system({
		"git",
		"clone",
		"--filter=blob:none",
		"--single-branch",
		"https://github.com/folke/lazy.nvim.git",
		lazypath,
	})
end
vim.opt.runtimepath:prepend(lazypath)

-- install plugins
local plugins = {
	"folke/tokyonight.nvim",
	{
		"stevearc/conform.nvim",
		config = function()
			require("conform").setup({
				log_level = vim.log.levels.DEBUG,
				-- add your config here
				formatters_by_ft = { swift = { "swift_format" } },
				formatters = {
					swift_format = {
						-- Uncomment this line to see the .swift-format file respected
						-- prepend_args = { "--configuration", ".swift-format" },
					},
				},
			})
		end,
	},
	-- add any other plugins here
}
require("lazy").setup(plugins, {
	root = root .. "/plugins",
})

vim.cmd.colorscheme("tokyonight")
-- add anything else here
vim.o.list = true

Additional context

I don't know if this is an issue with swift-format itself, but I can only reproduce it with conform.nvim

[stevearc]

Kind of crazy that the same command run on the command line produces different output. Is it being run from the same directory? If you add a cwd to the formatter, does that change anything?

[isaacthefallenapple]

@stevearc I've actually had a similar issue and I think using stdin is the problem. When you run <Package.swift swift-format it also doesn't respect the config (at least with my setup), whereas swift-format Package.swift does. I think using stdin = false and args = { '$FILENAME' } might work.

[heygarrett]

If you add a cwd to the formatter, does that change anything?

No change when using cwd = require("conform.util").root_file({ ".swift-format" }),

[stevearc]

@heygarrett can you confirm if the suggestion from @isaacthefallenapple works?

[heygarrett]

The suggestion from @isaacthefallenapple doesn't work for me, unfortunately.

[stevearc]

I unfortunately don't have a great way to reproduce this. Happy to provide pointers, but I think I'll need someone else to make a PR for this one.

[NSHaoSong]

@heygarrett I had similar issues, this the config that works for me:

formatters = {
  swift_format = {
    stdin = false,
    args = { "$FILENAME", "--in-place" },
  },
},
formatters_by_ft = {
  swift = { "swift_format" },
},

This is very similar to what @isaacthefallenapple suggested, just need to add --in-place.

apple/swift-format/README.md

• -i/--in-place: Overwrites the input files when formatting instead of
  printing the results to standard output. No backup of the original file is
  made before it is overwritten.

[NSHaoSong]

Here's the log I have with my config

10:14:17[DEBUG] Running formatters on /Users/haosong/Developer/apple/test-conform-swift-format/Package.swift: { "swift_format" }
10:14:17[INFO] Run swift_format on /Users/haosong/Developer/apple/test-conform-swift-format/Package.swift
10:14:17[DEBUG] Creating temp file /Users/haosong/Developer/apple/test-conform-swift-format/.conform.9683855.Package.swift
10:14:17[DEBUG] Run command: { "swift-format", "/Users/haosong/Developer/apple/test-conform-swift-format/.conform.9683855.Package.swift", "--in-place" }
10:14:17[DEBUG] swift_format exited with code 0
10:14:17[DEBUG] Cleaning up temp file /Users/haosong/Developer/apple/test-conform-swift-format/.conform.9683855.Package.swift

[NSHaoSong]

@stevearc I created a PR to add the extra args in the config file for swift_format: #283

Not sure if this is the best way to fix or not.

[heygarrett]

Fixed for me! Thanks!