Flag: --incompatible_depset_for_libraries_to_link_getter
Available since: 0.26 (June 2019 release)
Will be flipped in: 0.27 (September 2019 release)
Tracking issue: #8118

linking_context.libraries_to_link will return a depset instead of a list. To make code compatible with the list and the depset, simply check whether the value returned from linking_context.libraries_to_link has the attribute "to_list".

libraries_to_link = linking_context.libraries_to_link
if hasattr(libraries_to_link, "to_list"):
   # It's a depset
else:
  # It's a list