Add cet_transitive_paths() function

This function accepts a path name and a project name (default is the
current project name).  For each transitive dependency of the
specificied project name, the value of the corresponding path name is
appended to an output variable.

Modules/CetTest.cmake

@@ -21,6 +21,8 @@ include(CetMake)
 include(CetPackagePath)
 # May need to escape a string to avoid misinterpretation as regex
 include(CetRegexEscape)
+# Need to specify transitive BINARY_DIR paths for COMPILE_ONLY tests
+include(CetTransitivePaths)
 
 ##################
 # Programs and Modules
@@ -688,8 +690,8 @@ test ${test} must be defined already to be specified as a fixture for ${CET_TARG
         endif()
       endif()
       if (CET_COMPILE_ONLY)
-        _transitive_binary_directories(${CETMODULES_CURRENT_PROJECT_NAME})
-        list(JOIN TRANSITIVE_BINARY_DIRS ":" DIRS_FOR_PREFIX_PATH)
+        cet_transitive_paths(BINARY_DIR IN_TREE)
+        list(JOIN TRANSITIVE_PATHS_WITH_BINARY_DIR ":" DIRS_FOR_PREFIX_PATH)
         set(TEST_CMAKE_PREFIX_PATH "CMAKE_PREFIX_PATH=path_list_prepend:${DIRS_FOR_PREFIX_PATH}")
         get_test_property(${target} ENVIRONMENT_MODIFICATION CET_TEST_ENV_TMP)
         if (CET_TEST_ENV_TMP)
@@ -1100,15 +1102,3 @@ function(_update_defined_test_groups)
     FORCE
     )
 endfunction()
-
-function(_transitive_binary_directories PKG)
-  set(TRANSITIVE_BINARY_DIRS_TMP ${${PKG}_BINARY_DIR})
-  foreach(DEP IN LISTS CETMODULES_FIND_DEPS_PNAMES_PROJECT_${PKG})
-    if (${DEP}_IN_TREE)
-      _transitive_binary_directories(${DEP})
-      list(APPEND TRANSITIVE_BINARY_DIRS_TMP ${TRANSITIVE_BINARY_DIRS})
-    endif()
-  endforeach()
-  list(REMOVE_DUPLICATES TRANSITIVE_BINARY_DIRS_TMP)
-  set(TRANSITIVE_BINARY_DIRS ${TRANSITIVE_BINARY_DIRS_TMP} PARENT_SCOPE)
-endfunction()

Modules/CetTransitivePaths.cmake

@@ -0,0 +1,88 @@
+#[================================================================[.rst:
+CetTransitivePaths
+------------------
+
+Defines the function :commmand:`cet_transitive_paths`.
+
+#]================================================================]
+
+include_guard()
+
+#[================================================================[.rst:
+.. command:: cet_transitive_paths
+
+
+   Get a list of path values for all transitive dependencies of the
+   given project name.  For a given path name, the dependency tree of
+   the given project is searched according to the dependencies
+   specified via ``find_package``.
+
+   For example, if the path name ``"MY_PATH"`` is supplied, the
+   function will traverse the dependency structure and collect all
+   values of the path name ``"<project-or-dependency name>_MY_PATH"``.
+   The result can be accessed via the variable
+   ``"TRANSITIVE_PATHS_WITH_MY_PATH"``.
+
+   .. code-block:: cmake
+
+      cet_transitive_paths(<path-name> [<project-variable localization options>] [IN_TREE] [PROJECT <project-name>])
+
+   Options
+   ^^^^^^^
+
+   ``[PROJECT] <project-name>``
+     The top-level project from which the transitive dependency
+     traversal occurs.  (default
+     :variable:`${CETMODULES_CURRENT_PROJECT_NAME}
+     <CETMODULES_CURRENT_PROJECT_NAME>`).
+
+   ``IN_TREE``
+     Include paths only from projects that are included in the build tree.
+
+   Non-option arguments
+   ^^^^^^^^^^^^^^^^^^^^
+
+   ``[<path-name>]``
+     The name of the path that serves as the suffix for the top-level
+     project and all transitive dependencies.  The path name can be a
+     Cetmodules project variable, in which case the options to
+     :command:`cet_localize_pv` may also be provided.
+
+#]================================================================]
+
+function(cet_transitive_paths PATH)
+  cmake_parse_arguments(PARSE_ARGV 1 CTP "IN_TREE;BINARY;SOURCE;TRY_BINARY" "PROJECT" "")
+  cet_passthrough(FLAG APPEND CTP_BINARY clpv_args)
+  cet_passthrough(FLAG APPEND CTP_SOURCE clpv_args)
+  cet_passthrough(FLAG APPEND CTP_TRY_BINARY clpv_args)
+
+  set(PKG ${CETMODULES_CURRENT_PROJECT_NAME})
+  if (CTP_PROJECT)
+    set(PKG ${CTP_PROJECT})
+  endif()
+
+  _cet_transitive_project_names(${PKG} PNAMES_RESULT CTP_IN_TREE)
+  foreach(DEP IN LISTS PNAMES_RESULT)
+    if (DEFINED CACHE{CETMODULES_${PATH}_PROPERTIES_PROJECT_${DEP}})
+      cet_localize_pv(${DEP} ${PATH} ${clpv_args})
+    endif()
+    list(APPEND TRANSITIVE_PATHS_TMP ${${DEP}_${PATH}})
+  endforeach()
+  set(TRANSITIVE_PATHS_WITH_${PATH} ${TRANSITIVE_PATHS_TMP} PARENT_SCOPE)
+
+endfunction()
+
+function(_cet_transitive_project_names PKG RESULT_LIST)
+  set(RESULT_LIST_TMP ${${RESULT_LIST}})
+  foreach(DEP IN LISTS CETMODULES_FIND_DEPS_PNAMES_PROJECT_${PKG})
+    if (PKG STREQUAL DEP OR
+        (ARGN STREQUAL "IN_TREE" AND NOT ${DEP}_IN_TREE))
+      continue()
+    endif()
+    if (NOT "${DEP}" IN_LIST RESULT_LIST_TMP)
+      _cet_transitive_project_names("${DEP}" RESULT_LIST_TMP ${ARGN})
+    endif()
+  endforeach()
+  list(PREPEND RESULT_LIST_TMP ${PKG})
+  set(${RESULT_LIST} ${RESULT_LIST_TMP} PARENT_SCOPE)
+endfunction()