make sure crawl results are never overwritten with a blank ApiCrawler

backend/config/config.exs

@@ -62,9 +62,13 @@ config :backend, :crawler,
   crawl_interval_mins: 60,
   crawl_workers: 20,
   blacklist: [
+    # spam
     "gab.best",
+    # spam
     "4chan.icu",
+    # *really* doesn't want to be listed on fediverse.space
     "pleroma.site",
+    # dummy instances used for pleroma CI
     "pleroma.online"
   ],
   user_agent: "fediverse.space crawler",

backend/lib/backend/crawler/crawlers/gnu_social.ex

@@ -34,7 +34,7 @@ defmodule Backend.Crawler.Crawlers.GnuSocial do
   def crawl(domain, nodeinfo) do
     if nodeinfo == nil or
          nodeinfo |> Map.get(:user_count) |> is_above_user_threshold?() do
-      Map.merge(crawl_large_instance(domain), nodeinfo)
+      Map.merge(nodeinfo, crawl_large_instance(domain))
     else
       Map.merge(ApiCrawler.get_default(), nodeinfo)
     end

backend/lib/backend/scheduler.ex

@@ -166,7 +166,7 @@ defmodule Backend.Scheduler do
   Edges are only generated if
   * both instances have been succesfully crawled
   * neither of the instances have blocked each other
-  * there are interactions in each direction
+  * there are interactions in each direction (if :require_bidirectional_edges is true in config)
   """
   def generate_edges do
     now = get_now()