From 4a7310348298089837f70c434788cdb83928ccbb Mon Sep 17 00:00:00 2001
From: Levi Armstrong <levi.armstrong@gmail.com>
Date: Thu, 1 Aug 2019 17:28:48 -0500
Subject: [PATCH] Fix interface targets that do not have libraries (#1013)

---
 cmake/catkin_libraries.cmake | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/cmake/catkin_libraries.cmake b/cmake/catkin_libraries.cmake
index 814eb4349..0b090ca61 100644
--- a/cmake/catkin_libraries.cmake
+++ b/cmake/catkin_libraries.cmake
@@ -137,8 +137,10 @@ function(catkin_replace_imported_library_targets VAR)
       get_target_property(${lib}_imported ${lib} IMPORTED)
       if(${${lib}_type} STREQUAL "INTERFACE_LIBRARY")
         get_target_property(${lib}_interface_link_libraries ${lib} INTERFACE_LINK_LIBRARIES)
-        catkin_replace_imported_library_targets(${lib}_resolved_libs ${${lib}_interface_link_libraries})
-        list(APPEND result ${${lib}_resolved_libs})
+        if(${${lib}_interface_link_libraries})
+          catkin_replace_imported_library_targets(${lib}_resolved_libs ${${lib}_interface_link_libraries})
+          list(APPEND result ${${lib}_resolved_libs})
+        endif()
       elseif(${${lib}_imported})
         set(imported_libraries)  # empty list
         get_target_property(${lib}_imported_location ${lib} IMPORTED_LOCATION)