Use another exit code for internal error.

[risu729]

Description

I'm using lint-staged in my GitHub Actions and want to detect whether lint-staged has failed because of the failure of internal git diff or because of linters.

For example, git diff always throws an error if it is the first commit. (I can use the /dev/null hash to avoid it, but it is complicated and cannot handle other errors.)

I suggest using another exit code for internal errors, including git diff, like prettier.

I checked through the current behavior of lint-staged, and it always exits with 1, as defined here.

lint-staged/bin/lint-staged.js

Lines 124 to 129 in 26eee9d

	try {
	const passed = await lintStaged(options)
	process.exitCode = passed ? 0 : 1
	} catch {
	process.exitCode = 1
	}

[therealgilles]

Can the caught error be displayed when it's an internal error?

try {
  const passed = await lintStaged(options)
  process.exitCode = passed ? 0 : 1
} catch (e) {
  throw new Error(e) // <-- ADD THIS
  process.exitCode = 1
}