Don't export dependency on ucx (#172)

Until openucx/ucx#9614 is resolved ucxx cannot export its dependency on ucx and must instead rely on consumers to specify this.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Robert Maynard (https://github.com/robertmaynard)

URL: #172

cpp/CMakeLists.txt

@@ -71,11 +71,20 @@ rapids_cmake_support_conda_env(conda_env MODIFY_PREFIX_PATH)
 
 # ##################################################################################################
 # * compiler options ------------------------------------------------------------------------------
-rapids_find_package(
+find_package(
   ucx REQUIRED
-  BUILD_EXPORT_SET ucxx-exports
-  INSTALL_EXPORT_SET ucxx-exports
 )
+# Due to https://github.com/openucx/ucx/issues/9614, we cannot export the ucx
+# dependency because users would then have no control over whether ucx is found
+# multiple times, causing potential configure errors. Therefore, we do not
+# export the ucx dependency. Consumers of ucxx must find ucx themselves. Once
+# the above issue is resolved (see https://github.com/openucx/ucx/pull/9622) we
+# can remove the above find_package in favor of the commented out lines below.
+#rapids_find_package(
+#  ucx REQUIRED
+#  BUILD_EXPORT_SET ucxx-exports
+#  INSTALL_EXPORT_SET ucxx-exports
+#)
 
 # ##################################################################################################
 # * dependencies ----------------------------------------------------------------------------------

python/CMakeLists.txt

@@ -21,6 +21,7 @@ option(FIND_UCXX_CPP "Search for existing UCXX C++ installations before defaulti
 
 # If the user requested it we attempt to find UCXX.
 if(FIND_UCXX_CPP)
+  find_package(ucx REQUIRED)
   find_package(ucxx ${ucxx_version} REQUIRED COMPONENTS python)
 else()
   set(ucxx_FOUND OFF)