--- contrib/python/ipython/py3/IPython/core/completer.py	(index)
+++ contrib/python/ipython/py3/IPython/core/completer.py	(working tree)
@@ -1362,6 +1362,7 @@ def _make_signature(completion)-> str:
 
     """
 
+    return '(%s)'% ', '.join([f for f in (_formatparamchildren(p) for p in completion.params) if f])
     # it looks like this might work on jedi 0.17
     if hasattr(completion, 'get_signatures'):
         signatures = completion.get_signatures()
@@ -1921,1 +1922,1 @@ class IPCompleter(Completer):
-        interpreter = jedi.Interpreter(text[:offset], namespaces)
+        interpreter = jedi.Interpreter(text[:offset], namespaces, column=cursor_column, line=cursor_line + 1)
@@ -1948,1 +1949,1 @@ class IPCompleter(Completer):
-            return filter(completion_filter, interpreter.complete(column=cursor_column, line=cursor_line + 1))
+            return filter(completion_filter, interpreter.completions())
--- contrib/python/ipython/py3/IPython/core/completerlib.py	(index)
+++ contrib/python/ipython/py3/IPython/core/completerlib.py	(working tree)
@@ -20,2 +20,3 @@ These are all loaded by default by IPython.
 import inspect
+import itertools
 import os
@@ -40,4 +41,6 @@ from IPython import get_ipython
 from typing import List
 
+from __res import importer
+
 #-----------------------------------------------------------------------------
 # Globals and constants
@@ -64,6 +67,50 @@ magic_run_re = re.compile(r'.*(\.ipy|\.ipynb|\.py[w]?)$')
 #-----------------------------------------------------------------------------
 
 
+arcadia_rootmodules_cache = None
+arcadia_modules_cache = None
+
+
+def arcadia_init_cache():
+    global arcadia_rootmodules_cache, arcadia_modules_cache
+    arcadia_rootmodules_cache = set()
+    arcadia_modules_cache = {}
+
+    all_modules = itertools.chain(
+        sys.builtin_module_names,
+        importer.memory
+    )
+
+    for name in all_modules:
+        path = name.split('.')
+        arcadia_rootmodules_cache.add(path[0])
+
+        prefix = path[0]
+        for element in path[1:]:
+            if element == '__init__':
+                continue
+
+            arcadia_modules_cache.setdefault(prefix, set()).add(element)
+            prefix += '.' + element
+
+    arcadia_rootmodules_cache = sorted(arcadia_rootmodules_cache)
+    arcadia_modules_cache = {k: sorted(v) for k, v in arcadia_modules_cache.items()}
+
+
+def arcadia_module_list(mod):
+    if arcadia_modules_cache is None:
+        arcadia_init_cache()
+
+    return arcadia_modules_cache.get(mod, ())
+
+
+def arcadia_get_root_modules():
+    if arcadia_rootmodules_cache is None:
+        arcadia_init_cache()
+
+    return arcadia_rootmodules_cache
+
+
 def module_list(path: str) -> List[str]:
     """
     Return the list containing the names of the modules available in the given
@@ -176,7 +223,8 @@ def try_import(mod: str, only_modules=False) -> List[str]:
     except:
         return []
 
-    m_is_init = '__init__' in (getattr(m, '__file__', '') or '')
+    filename = getattr(m, '__file__', '')
+    m_is_init = '__init__' in (filename or '') or filename == mod
 
     completions = []
     if (not hasattr(m, '__file__')) or (not only_modules) or m_is_init:
@@ -190,9 +238,10 @@ def try_import(mod: str, only_modules=False) -> List[str]:
         file_path = os.path.dirname(file_)  # type: ignore
         if file_path is not None:
             completions.extend(module_list(file_path))
+        completions.extend(arcadia_module_list(mod))
     completions_set = {c for c in completions if isinstance(c, str)}
     completions_set.discard('__init__')
-    return list(completions_set)
+    return sorted(completions_set)
 
 
 #-----------------------------------------------------------------------------
@@ -242,10 +290,10 @@ def module_completion(line):
     # 'from xy<tab>' or 'import xy<tab>'
     if nwords < 3 and (words[0] in {'%aimport', 'import', 'from'}) :
         if nwords == 1:
-            return get_root_modules()
+            return arcadia_get_root_modules()
         mod = words[1].split('.')
         if len(mod) < 2:
-            return get_root_modules()
+            return arcadia_get_root_modules()
         completion_list = try_import('.'.join(mod[:-1]), True)
         return ['.'.join(mod[:-1] + [el]) for el in completion_list]
 
--- contrib/python/ipython/py3/IPython/core/profiledir.py	(index)
+++ contrib/python/ipython/py3/IPython/core/profiledir.py	(working tree)
@@ -126,18 +126,12 @@ class ProfileDir(LoggingConfigurable):
     def check_startup_dir(self, change=None):
         if self._mkdir(self.startup_dir):
             readme = os.path.join(self.startup_dir, "README")
-            src = os.path.join(
-                get_ipython_package_dir(), "core", "profile", "README_STARTUP"
-            )
 
-            if os.path.exists(src):
-                if not os.path.exists(readme):
-                    shutil.copy(src, readme)
-            else:
-                self.log.warning(
-                    "Could not copy README_STARTUP to startup dir. Source file %s does not exist.",
-                    src,
-                )
+            if not os.path.exists(readme):
+                import pkgutil
+                with open(readme, "wb") as f:
+                    f.write(pkgutil.get_data(__name__, "profile/README_STARTUP"))
+                return
 
     @observe('security_dir')
     def check_security_dir(self, change=None):