Prettier 3.2.3 incorrectly formats .estlintrc.json

[fstaffa]

After updating to prettier 3.2.3, it formats .eslintrc.json with trailing commas, here is an example:

{
	"parser": "@typescript-eslint/parser",
	"extends": ["plugin:@typescript-eslint/recommended", "prettier"],
	"plugins": ["no-only-tests"],
	"parserOptions": {
		"ecmaVersion": 2018,
		"sourceType": "module", <--
	},
	"ignorePatterns": ["node_modules/", "build"],
	"rules": {
		"no-console": ["off"],
		"@typescript-eslint/consistent-type-assertions": [
			"error",
			{
				"assertionStyle": "angle-bracket", <--
			}, <--
		],
		"@typescript-eslint/no-explicit-any": "off",
		"@typescript-eslint/no-var-requires": "off",
		"@typescript-eslint/explicit-function-return-type": "off",
		"@typescript-eslint/no-use-before-define": "off",
		"@typescript-eslint/no-empty-function": "off",
		"prefer-const": "off",
		"no-only-tests/no-only-tests": ["error"], <--
	}, <--
}

When running eslint 8.56.0, it throw an error
Cannot read config file: [foldername]/.eslintrc.json Error: Unexpected token } in JSON at position 210

I assume this is related to #15881 , and that it incorrectly identifies which files are json and which jsonc. While eslint config specifies it allows comments, I am not sure it implies it also accepts trailing commas https://eslint.org/docs/latest/use/configure/configuration-files#configuration-file-formats

[Edit]: Here are minimal replication steps:

1. checkout https://github.com/fstaffa/prettier-eslintrc-issue
2. run npm ci
3. run npm run eslint (works as exptected)
4. run npm run prettier (changes .eslintrc.json)
5. run npm run eslint (fails with error similar to what was reported above)

[henrikvolmer]

We have the same issue. Please revert #15927 or fix the problem.

[fisker]

Close in favor of #15946

[fstaffa]

I think you meant #15945

[fisker]

Yes, thank you!