"start line should be at least 1" removing first line from file

[ghost]

Issue:

When removing the first line from a file, the pre-commit hook fails with the following error, preventing commit.

[test-clang-format-repo]$ git commit -m "Test file remove first line"
error: start line should be at least 1

The apply-format script failed.
[test-clang-format-repo]$

Steps to reproduce:

1. mkdir test-clang-format-repo && cd test-clang-format-repo && git init .
2. /path/to/this/repo/git-pre-commit-format install
3. Create TestFile.cc with:

#include <iostream>

int main() {
  std::cout << "Hello, clang" << std::endl;
  return 0;
    }

(note first line is empty)

4. git add 'TestFile.cc' && git commit -m "test file"
5. accept the suggested correction (to the indentation)
6. edit TestFile.cc and remove the first (empty) line
7. git add 'TestFile.cc' && git commit -m "remove first line"

Expected behaviour:

• commit is successful

Actual behaviour:

error: start line should be at least 1

The apply-format script failed.

[test-clang-format-repo]$ git status
On branch main
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
        modified:   Testfile.cc

Change is still stashed.