Use a thread to import slow modules in the background

aider/main.py

@@ -2,6 +2,7 @@ import configparser
 import os
 import re
 import sys
+import threading
 from pathlib import Path
 
 import git
@@ -536,6 +537,8 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
             return 1
         return
 
+    threading.Thread(target=load_slow_imports).start()
+
     while True:
         try:
             coder.run()
@@ -545,6 +548,17 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
             coder.show_announcements()
 
 
+def load_slow_imports():
+    # These imports are deferred in various ways to
+    # improve startup time.
+    # This func is called in a thread to load them in the background
+    # while we wait for the user to type their first message.
+    import httpx  # noqa: F401
+    import litellm  # noqa: F401
+    import networkx  # noqa: F401
+    import numpy  # noqa: F401
+
+
 if __name__ == "__main__":
     status = main()
     sys.exit(status)

aider/repomap.py

@@ -58,15 +58,6 @@ class RepoMap:
         self.token_count = main_model.token_count
         self.repo_content_prefix = repo_content_prefix
 
-    def import_nx(self):
-        """Import nx as needed, to avoid 250ms on launch"""
-
-        if self.nx:
-            return
-        import networkx as nx
-
-        self.nx = nx
-
     def get_repo_map(self, chat_files, other_files, mentioned_fnames=None, mentioned_idents=None):
         if self.max_map_tokens <= 0:
             return
@@ -239,7 +230,7 @@ class RepoMap:
             )
 
     def get_ranked_tags(self, chat_fnames, other_fnames, mentioned_fnames, mentioned_idents):
-        self.import_nx()
+        import networkx as nx
 
         defines = defaultdict(set)
         references = defaultdict(list)
@@ -306,7 +297,7 @@ class RepoMap:
 
         idents = set(defines.keys()).intersection(set(references.keys()))
 
-        G = self.nx.MultiDiGraph()
+        G = nx.MultiDiGraph()
 
         for ident in idents:
             definers = defines[ident]
@@ -337,7 +328,7 @@ class RepoMap:
             pers_args = dict()
 
         try:
-            ranked = self.nx.pagerank(G, weight="weight", **pers_args)
+            ranked = nx.pagerank(G, weight="weight", **pers_args)
         except ZeroDivisionError:
             return []