set_version_flag seems broken

[delpinux]

Hi.

It seems that set_version_flag behavior changed recently.
Previously, even using required options, when using the version flag application just printed the version as expected and exited.
Now, returns an error and does not print version anymore.

I just tested with today's main branch a41ba814b3202aeb35f6ed36f0fde80402bf85cc.

Here is a simple reproducer.

#include <CLI/CLI.hpp>
#include <string>

int main(int argc, char*argv[]) {
  CLI::App app{"reproducer"};

  std::string filename;
  auto filename_option= app.add_option("filename", filename, "data file")
    ->check(CLI::ExistingFile)
    ->required();

  auto version_flag = app.set_version_flag("-v,--version", "0.0.1");

  try {
    app.parse(argc, argv);
  }
  catch (const CLI::ParseError& e) {
    std::exit(app.exit(e, std::cout, std::cerr));
  }

  return 0;
}

running it produces

$ ./a.out --version
filename is required
Run with --help for more information.

and adding a useless existing filename gives

$ ./a.out --version a_file
0.0.1

Thanks,
Stéphane.

[phlptp]

hmmm, I think I know what caused this, need to think how to resolve it though as the change was fixing a different issue. Thanks.