Better control when dumping import state

Tools/scripts/import_diagnostics.py

@@ -7,27 +7,25 @@ from pprint import pprint
 
 def _dump_state(args):
     print(sys.version)
-    print("sys.path:")
-    pprint(sys.path)
-    print("sys.meta_path")
-    pprint(sys.meta_path)
-    print("sys.path_hooks")
-    pprint(sys.path_hooks)
-    print("sys.path_importer_cache")
-    pprint(sys.path_importer_cache)
-    print("sys.modules:")
-    pprint(sys.modules)
+    for name in args.attributes:
+        print("sys.{}:".format(name))
+        pprint(getattr(sys, name))
+
+def _add_dump_args(cmd):
+    cmd.add_argument("attributes", metavar="ATTR", nargs="+",
+                     help="sys module attribute to display")
 
 COMMANDS = (
-  ("dump", "Dump import state", _dump_state),
+  ("dump", "Dump import state", _dump_state, _add_dump_args),
 )
 
 def _make_parser():
     parser = argparse.ArgumentParser()
     sub = parser.add_subparsers(title="Commands")
-    for name, description, implementation in COMMANDS:
+    for name, description, implementation, add_args in COMMANDS:
         cmd = sub.add_parser(name, help=description)
         cmd.set_defaults(command=implementation)
+        add_args(cmd)
     return parser
 
 def main(args):