only allow add of r2d_image when using shared config

jsc_custom/spawner/spawner.py

@@ -566,32 +566,22 @@ def filter_events(spawner, event):
     return event
 
 
-async def recursive_share_replace(user_options, replace_options):
-    result = {}
-
-    for key in set(user_options.keys()).union(replace_options.keys()):
-        uval = user_options.get(key)
-        rval = replace_options.get(key)
-
-        if isinstance(uval, dict) and isinstance(rval, dict):
-            result[key] = await recursive_share_replace(uval, rval)
-        elif key in replace_options:
-            result[key] = rval
-        else:
-            result[key] = uval
-
-    return result
-
-
 async def custom_user_options(spawner, user_options):
     from ..orm.share import UserOptionsShares
 
     log_user_options = copy.deepcopy(user_options)
     if "share_id" in user_options.keys():
-        share_user_options = UserOptionsShares.find_by_share_id(
+        r2d_image = None
+        user_options.get("repo2docker", {}).get("image", None)
+        user_options = UserOptionsShares.find_by_share_id(
             spawner.user.db, user_options["share_id"]
         ).user_options
-        user_options = await recursive_share_replace(user_options, share_user_options)
+        if (
+            r2d_image
+            and user_options.get("option", "") == "repo2docker"
+            and "repo2docker" in user_options.keys()
+        ):
+            user_options["repo2docker"]["image"] = r2d_image
 
     ret = await recursive_decrypt(user_options.get("secret_keys", []), user_options)
     log_extras = {