A semicolon is accidentally removed

[m-shaka]

Environment information

CLI:
  Version:                      1.4.1
  Color support:                true

Platform:
  CPU Architecture:             aarch64
  OS:                           macos

Environment:
  BIOME_LOG_DIR:                unset
  NO_COLOR:                     unset
  TERM:                         "xterm-256color"
  JS_RUNTIME_VERSION:           "v18.14.0"
  JS_RUNTIME_NAME:              "node"
  NODE_PACKAGE_MANAGER:         "npm/9.7.2"

Biome Configuration:
  Status:                       Loaded successfully
  Formatter disabled:           false
  Linter disabled:              true
  Organize imports disabled:    false
  VCS disabled:                 true

Workspace:
  Open Documents:               0

Configuration

{
	"$schema": "https://biomejs.dev/schemas/1.4.1/schema.json",
	"organizeImports": {
		"enabled": true
	},
	"linter": {
		"enabled": false,
		"rules": {
			"recommended": true
		}
	},
	"files": {
		"include": [
			"**/*.ts"
		]
	},
	"formatter": {
		"enabled": true
	},
	"javascript": {
		"formatter": {
			"lineWidth": 40,
			"semicolons": "asNeeded"
		}
	}
}

Playground link

https://biomejs.dev/playground/?lineWidth=40&semicolons=as-needed&enabledLinting=false&importSortingEnabled=false&code=ZgB1AG4AYwB0AGkAbwBuACAAZgB1AG4APABUAD4AKAAKAAkAZgBuADoAIAAoAGEAcgBnAHMAOgAgAHsACgAJAAkAYQA6ACAAcwB0AHIAaQBuAGcACgAJAAkAYgA6ACAAcwB0AHIAaQBuAGcACgAJAH0AKQAgAD0APgAgAHYAbwBpAGQALAAKACkAIAB7AAoACQBmAG4AKAB7ACAAYQA6ACAAIgBhACIALAAgAGIAOgAgACIAYgAiACAAfQApAAoAfQAKAAoAZgB1AG4AKAAoAGEAcgBnAHMAOgAgAHsAIABhADoAIABzAHQAcgBpAG4AZwA7ACAAYgA6ACAAcwB0AHIAaQBuAGcAIAB9ACkAIAA9AD4AIAB7AAoACQByAGUAdAB1AHIAbgAgAGEAcgBnAHMACgB9ACkACgA%3D

Code of Conduct

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Description

fun((args: { a: string; b: string }) => { is formatted to fun((args: { a: string b: string }) => {, which is syntactically broken.
lineWidth setting is 40 and the length of this line is 41. If you rename args to a shorter name like obj, the semicolon won't be removed. If you rename it to a longer name, the line will be line-wrapped.

[faultyserver]

(I spoke too soon in earlier comments and misunderstood the issue. Correcting now with real information).

Minimal repro, semicolons set to asNeeded and line width 40:

foo((args: {a: string; b: string}) => {
  return a;
})

// Output
foo((args: {a: string b: string}) => {
  return a;
})

Playground Link

The issue here I think is because the if_group_fits_on_line(";") is used even in the flattened case of the best_fitting for the call argument, though I'm not sure why it doesn't get printed, then. Just comparing the IR with Prettier, that's the only difference.

[m-shaka]

Thank you for your quick fix! @faultyserver