old_contents: #!/usr/bin/env python
  from setuptools import setup
  
  try:
      setup(use_scm_version=True)
  except LookupError as e:
      # .git has been removed, and this is not a package created by sdist
      # This is the case e.g. of a remote deployment with PyCharm Professional
      if not str(e).startswith("setuptools-scm was unable to detect version"):
          raise
      setup(version="999")
  
new_contents: #!/usr/bin/env python
  from setuptools import setup
  
  setup(use_scm_version={"fallback_version": "999"})
  
subject: use the fallback_version option to avoid errors on source checkouts (#4358)