From e665e6f160e23545b441ceb7f9ca3c1cd7b6d1ea Mon Sep 17 00:00:00 2001
From: ptaylor <paul.e.taylor@me.com>
Date: Tue, 4 Oct 2022 11:00:57 -0700
Subject: [PATCH] force CPM to download Legion if legion_dir or legion_src_dir
 is not explicitly provided

---
 cmake/thirdparty/get_legion.cmake | 20 +++++++++++---------
 install.py                        |  4 +++-
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/cmake/thirdparty/get_legion.cmake b/cmake/thirdparty/get_legion.cmake
index 344fc2d2c..5faf54023 100644
--- a/cmake/thirdparty/get_legion.cmake
+++ b/cmake/thirdparty/get_legion.cmake
@@ -37,16 +37,18 @@ function(find_or_configure_legion)
       BUILD_EXPORT_SET   legate-core-exports
       INSTALL_EXPORT_SET legate-core-exports)
 
-  # First try to find Legion via find_package()
-  # so the `Legion_USE_*` variables are visible
-  # Use QUIET find by default.
-  set(_find_mode QUIET)
-  # If Legion_DIR/Legion_ROOT are defined as something other than empty or NOTFOUND
-  # use a REQUIRED find so that the build does not silently download Legion.
-  if(Legion_DIR OR Legion_ROOT)
-    set(_find_mode REQUIRED)
+  if((NOT CPM_Legion_SOURCE) AND (NOT CPM_DOWNLOAD_Legion))
+    # First try to find Legion via find_package()
+    # so the `Legion_USE_*` variables are visible
+    # Use QUIET find by default.
+    set(_find_mode QUIET)
+    # If Legion_DIR/Legion_ROOT are defined as something other than empty or NOTFOUND
+    # use a REQUIRED find so that the build does not silently download Legion.
+    if(Legion_DIR OR Legion_ROOT)
+      set(_find_mode REQUIRED)
+    endif()
+    rapids_find_package(Legion ${PKG_VERSION} EXACT CONFIG ${_find_mode} ${FIND_PKG_ARGS})
   endif()
-  rapids_find_package(Legion ${PKG_VERSION} EXACT CONFIG ${_find_mode} ${FIND_PKG_ARGS})
 
   if(Legion_FOUND)
     message(STATUS "CPM: using local package Legion@${PKG_VERSION}")
diff --git a/install.py b/install.py
index 6566ca68b..6cd0ca3a7 100755
--- a/install.py
+++ b/install.py
@@ -454,8 +454,10 @@ def validate_path(path):
         cmake_flags += ["-DThrust_ROOT=%s" % thrust_dir]
     if legion_dir:
         cmake_flags += ["-DLegion_ROOT=%s" % legion_dir]
-    if legion_src_dir:
+    elif legion_src_dir:
         cmake_flags += ["-DCPM_Legion_SOURCE=%s" % legion_src_dir]
+    else:
+        cmake_flags += ["-DCPM_DOWNLOAD_Legion=ON"]
     if legion_url:
         cmake_flags += ["-Dlegate_core_LEGION_REPOSITORY=%s" % legion_url]
     if legion_branch: