Check correctly for things that could be Python packages.

runhouse/resources/packages/package.py

@@ -81,6 +81,10 @@ def __str__(self):
  return f"Package: {self.install_target.path}"
  return f"Package: {self.install_target}"
 
+ @staticmethod
+ def is_python_package_string(s: str):
+ return re.match(r"^[a-zA-Z0-9\._-]+$", s) is not None
+
  @staticmethod
  def _find_locally_installed_version(package_name: str):
  try:
@@ -488,7 +492,7 @@ def from_string(specifier: str, dryrun=False):
  # If we are just defaulting to pip, attempt to install the same version of the package
  # that is already installed locally
  # Check if the target is only letters, nothing else. This means its a string like 'numpy'.
- if install_method == "pip" and target.isalpha():
+ if install_method == "pip" and Package.is_python_package_string(target):
  locally_installed_version = Package._find_locally_installed_version(target)
  if locally_installed_version:
  target = f"{target}=={locally_installed_version}"