Reduce complexity by avoiding to redefine a helper function inside a loop that...

Reduce complexity by avoiding to redefine a helper function inside a loop that does not depend on the loop state

Cython/Build/Dependencies.py

@@ -897,19 +897,20 @@ def cythonize(module_list, exclude=None, nthreads=0, aliases=None, quiet=False,
     deps = create_dependency_tree(ctx, quiet=quiet)
     build_dir = getattr(options, 'build_dir', None)
 
-    modules_by_cfile = collections.defaultdict(list)
-    to_compile = []
-    for m in module_list:
-        if build_dir:
-            root = os.getcwd()  # distutil extension depends are relative to cwd
-            def copy_to_build_dir(filepath, root=root):
+    def copy_to_build_dir(filepath, root=os.getcwd()):
         filepath_abs = os.path.abspath(filepath)
         if os.path.isabs(filepath):
             filepath = filepath_abs
         if filepath_abs.startswith(root):
+            # distutil extension depends are relative to cwd
             mod_dir = join_path(build_dir,
                                 os.path.dirname(_relpath(filepath, root)))
             copy_once_if_newer(filepath_abs, mod_dir)
+
+    modules_by_cfile = collections.defaultdict(list)
+    to_compile = []
+    for m in module_list:
+        if build_dir:
             for dep in m.depends:
                 copy_to_build_dir(dep)