1 files changed, 8 insertions, 8 deletions
diff --git a/Modules/ExternalData.cmake b/Modules/ExternalData.cmake
index 02d2b157d9..a0bffe7716 100644
--- a/Modules/ExternalData.cmake
+++ b/Modules/ExternalData.cmake
@@ -473,10 +473,10 @@ function(ExternalData_expand_arguments target outArgsVar)
         if("x${piece}" MATCHES "^x${data_regex}$")
           # Replace this DATA{}-piece with a file path.
           _ExternalData_arg("${target}" "${piece}" "${CMAKE_MATCH_1}" file)
-          set(outArg "${outArg}${file}")
+          string(APPEND outArg "${file}")
         else()
           # No replacement needed for this piece.
-          set(outArg "${outArg}${piece}")
+          string(APPEND outArg "${piece}")
         endif()
       endforeach()
     else()
@@ -696,12 +696,12 @@ macro(_ExternalData_arg_associated)
     get_filename_component(reldir "${reldata}" PATH)
   endif()
   if(reldir)
-    set(reldir "${reldir}/")
+    string(APPEND reldir "/")
   endif()
   _ExternalData_exact_regex(reldir_regex "${reldir}")
   if(recurse_option)
     set(glob GLOB_RECURSE)
-    set(reldir_regex "${reldir_regex}(.+/)?")
+    string(APPEND reldir_regex "(.+/)?")
   else()
     set(glob GLOB)
   endif()
@@ -717,7 +717,7 @@ macro(_ExternalData_arg_associated)
   set(all "")
   set(sep "")
   foreach(regex ${associated_regex})
-    set(all "${all}${sep}${reldir_regex}${regex}")
+    string(APPEND all "${sep}${reldir_regex}${regex}")
     set(sep "|")
   endforeach()
   _ExternalData_arg_find_files(${glob} "${reldir}" "${all}")
@@ -978,9 +978,9 @@ function(_ExternalData_download_object name hash algo var_obj)
     else()
       _ExternalData_download_file("${url}" "${tmp}" err errMsg)
     endif()
-    set(tried "${tried}\n  ${url}")
+    string(APPEND tried "\n  ${url}")
     if(err)
-      set(tried "${tried} (${errMsg})")
+      string(APPEND tried " (${errMsg})")
     else()
       # Verify downloaded object.
       _ExternalData_compute_hash(dl_hash "${algo}" "${tmp}")
@@ -988,7 +988,7 @@ function(_ExternalData_download_object name hash algo var_obj)
         set(found 1)
         break()
       else()
-        set(tried "${tried} (wrong hash ${algo}=${dl_hash})")
+        string(APPEND tried " (wrong hash ${algo}=${dl_hash})")
         if("$ENV{ExternalData_DEBUG_DOWNLOAD}" MATCHES ".")
           file(RENAME "${tmp}" "${store}/${algo}/${dl_hash}")
         endif()