From 843290e2a502554d42c2a686bf1efb96a1eaa5d9 Mon Sep 17 00:00:00 2001
From: ptaylor <paul.e.taylor@me.com>
Date: Fri, 2 Jul 2021 22:55:35 -0500
Subject: [PATCH] always add faiss library alias if it's missing

---
 cpp/cmake/thirdparty/get_faiss.cmake | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/cpp/cmake/thirdparty/get_faiss.cmake b/cpp/cmake/thirdparty/get_faiss.cmake
index 626af5196c..8a88f9694e 100644
--- a/cpp/cmake/thirdparty/get_faiss.cmake
+++ b/cpp/cmake/thirdparty/get_faiss.cmake
@@ -40,7 +40,10 @@ function(find_and_configure_faiss)
 
     if(FAISS_ADDED)
       target_include_directories(faiss INTERFACE $<BUILD_INTERFACE:${FAISS_SOURCE_DIR}>)
-      add_library(FAISS::FAISS ALIAS faiss)
+    endif()
+
+    if(TARGET faiss AND NOT TARGET FAISS::FAISS)
+        add_library(FAISS::FAISS ALIAS faiss)
     endif()
 
 endfunction()