Fix docker tmp/ and extensions/ handling for docker. might also work for symlinks

modules/ui_extensions.py

@@ -9,6 +9,8 @@ import git
 
 import gradio as gr
 import html
+import shutil
+import errno
 
 from modules import extensions, shared, paths
 
@@ -132,7 +134,18 @@ def install_extension_from_url(dirname, url):
         repo = git.Repo.clone_from(url, tmpdir)
         repo.remote().fetch()
 
+        try:
             os.rename(tmpdir, target_dir)
+        except OSError as err:
+            # TODO what does this do on windows? I think it'll be a different error code but I don't have a system to check it
+            # Shouldn't cause any new issues at least but we probably want to handle it there too.
+            if err.errno == errno.EXDEV:
+                # Cross device link, typical in docker or when tmp/ and extensions/ are on different file systems
+                # Since we can't use a rename, do the slower but more versitile shutil.move()
+                shutil.move(tmpdir, target_dir)
+            else:
+                # Something else, not enough free space, permissions, etc.  rethrow it so that it gets handled.
+                raise(err)
 
         import launch
         launch.run_extension_installer(target_dir)