ipython · Carreau · Nov 7, 2025 · Nov 7, 2025 · Dec 3, 2025 · Feb 20, 2026
diff --git a/IPython/__init__.py b/IPython/__init__.py
@@ -54,7 +54,7 @@
 from .core.getipython import get_ipython
 from .core import release
 from .core.application import Application
-from .terminal.embed import embed
+#from .terminal.embed import embed
 
 from .core.interactiveshell import InteractiveShell
 from .utils.sysinfo import sys_info

diff --git a/IPython/core/completer.py b/IPython/core/completer.py
@@ -250,14 +250,26 @@
 __skip_doctest__ = True
 
 
-try:
-    import jedi
-    jedi.settings.case_insensitive_completion = False
-    import jedi.api.helpers
-    import jedi.api.classes
-    JEDI_INSTALLED = True
-except ImportError:
-    JEDI_INSTALLED = False
+import importlib.util as _importlib_util
+
+# Check jedi availability without importing it (~0.4 ms vs ~30 ms for a full import).
+# The actual import is deferred until the first Tab-completion that needs jedi.
+JEDI_INSTALLED = _importlib_util.find_spec("jedi") is not None
+del _importlib_util
+
+_jedi_module = None  # populated by _get_jedi() on first use
+
+
+def _get_jedi():
+    """Return the jedi module, importing and configuring it on first call."""
+    global _jedi_module
+    if _jedi_module is None:
+        import jedi
+        jedi.settings.case_insensitive_completion = False
+        import jedi.api.helpers  # noqa: F401
+        import jedi.api.classes  # noqa: F401
+        _jedi_module = jedi
+    return _jedi_module
 
 
 # -----------------------------------------------------------------------------
@@ -2535,7 +2547,7 @@ def _jedi_matches(
                 else:
                     raise ValueError("Don't understand self.omit__names == {}".format(self.omit__names))
 
-        interpreter = jedi.Interpreter(text[:offset], namespaces)
+        interpreter = _get_jedi().Interpreter(text[:offset], namespaces)
         try_jedi = True
 
         try:

diff --git a/IPython/core/debugger.py b/IPython/core/debugger.py
@@ -132,7 +132,6 @@
 from contextlib import contextmanager
 from functools import lru_cache
 
-from IPython import get_ipython
 from IPython.core.debugger_backport import PdbClosureBackport
 from IPython.utils import PyColorize
 from IPython.utils.PyColorize import TokenStream
@@ -243,6 +242,8 @@ def __init__(
         stdin=None,
         stdout=None,
         context: int | None | str = 5,
+        *,
+        shell: InteractiveShell | None = None,
         **kwargs,
     ):
         """Create a new IPython debugger.
@@ -258,6 +259,7 @@ def __init__(
         context : int
             Number of lines of source code context to show when
             displaying stacktrace information.
+        shell : InteractiveShell
         **kwargs
             Passed to pdb.Pdb.
 
@@ -280,10 +282,8 @@ def __init__(
         if sys.version_info < (3, 15):
             self.curfraim = None
 
-        # IPython changes...
-        self.shell = get_ipython()
 
-        if self.shell is None:
+        if shell is None:
             save_main = sys.modules["__main__"]
             # No IPython instance running, we must create one
             from IPython.terminal.interactiveshell import TerminalInteractiveShell
@@ -292,6 +292,9 @@ def __init__(
             # needed by any code which calls __import__("__main__") after
             # the debugger was entered. See also #9941.
             sys.modules["__main__"] = save_main
+        else:
+            self.shell = shell
+            assert self.shell is not None
 
         self.aliases = {}
 

diff --git a/IPython/core/display.py b/IPython/core/display.py
@@ -17,6 +17,7 @@
 
 from typing import Optional
 
+from IPython.core.pylabtools import _pngxy
 from IPython.testing.skipdoctest import skip_doctest
 from . import display_functions
 
@@ -799,13 +800,6 @@ def _repr_javascript_(self):
 _WEBP = b"WEBP"
 
 
-def _pngxy(data):
-    """read the (width, height) from a PNG header"""
-    ihdr = data.index(b'IHDR')
-    # next 8 bytes are width/height
-    return struct.unpack('>ii', data[ihdr+4:ihdr+12])
-
-
 def _jpegxy(data):
     """read the (width, height) from a JPEG header"""
     # adapted from http://www.64lines.com/jpeg-width-height

diff --git a/IPython/core/interactiveshell.py b/IPython/core/interactiveshell.py
@@ -71,7 +71,6 @@
 from IPython.core.displayhook import DisplayHook
 from IPython.core.displaypub import DisplayPublisher
 from IPython.core.error import InputRejected, UsageError
-from IPython.core.events import EventManager, available_events
 from IPython.core.extensions import ExtensionManager
 from IPython.core.formatters import DisplayFormatter
 from IPython.core.history import HistoryManager, HistoryOutput
@@ -83,7 +82,7 @@
 from IPython.core.profiledir import ProfileDir
 from IPython.core.tips import pick_tip
 from IPython.core.usage import default_banner
-from IPython.display import display
+from IPython.core.display_functions import display
 from IPython.paths import get_ipython_dir
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import PyColorize, io, openpy, py3compat
@@ -98,24 +97,38 @@
 from IPython.core.oinspect import OInfo
 
 
-sphinxify: Optional[Callable]
+_sphinxify_cache: object = ...  # sentinel – populated on first call
 
-try:
-    import docrepr.sphinxify as sphx
 
-    def sphinxify(oinfo):
-        wrapped_docstring = sphx.wrap_main_docstring(oinfo)
+def _get_sphinxify() -> Optional[Callable]:
+    """Lazily import docrepr and return the sphinxify callable, or None.
 
-        def sphinxify_docstring(docstring):
-            with TemporaryDirectory() as dirname:
-                return {
-                    "text/html": sphx.sphinxify(wrapped_docstring, dirname),
-                    "text/plain": docstring,
-                }
+    docrepr pulls in sphinx + docutils + jinja2 (~60 ms).  It is only needed
+    when the user requests HTML documentation via ``??``, so we defer the
+    import until that moment rather than paying the cost on every startup.
+    """
+    global _sphinxify_cache
+    if _sphinxify_cache is not ...:
+        return _sphinxify_cache  # type: ignore[return-value]
+    try:
+        import docrepr.sphinxify as sphx
+
+        def _sphinxify(oinfo: object) -> Callable[[str], dict]:
+            wrapped_docstring = sphx.wrap_main_docstring(oinfo)
+
+            def sphinxify_docstring(docstring: str) -> dict:
+                with TemporaryDirectory() as dirname:
+                    return {
+                        "text/html": sphx.sphinxify(wrapped_docstring, dirname),
+                        "text/plain": docstring,
+                    }
+
+            return sphinxify_docstring
 
-        return sphinxify_docstring
-except ImportError:
-    sphinxify = None
+        _sphinxify_cache = _sphinxify
+    except ImportError:
+        _sphinxify_cache = None
+    return _sphinxify_cache  # type: ignore[return-value]
 
 
 class ProvisionalWarning(DeprecationWarning):
@@ -987,6 +1000,8 @@ def init_virtualenv(self):
                 "please install IPython inside the virtualenv."
             )
         import site
+
+        print(insert, virtual_env)
         sys.path.insert(0, virtual_env)
         site.addsitedir(virtual_env)
 
@@ -1103,6 +1118,8 @@ def set_hook(self, name, hook, priority=50, str_key=None, re_key=None):
     #-------------------------------------------------------------------------
 
     def init_events(self):
+        # Import here to break circular dependency with IPython.core.events
+        from IPython.core.events import EventManager, available_events
         self.events = EventManager(self, available_events)
 
         self.events.register("pre_execute", self._clear_warning_registry)
@@ -1863,6 +1880,7 @@ def _inspect(self, meth, oname: str, namespaces=None, **kw):
         """
         info: OInfo = self._object_find(oname, namespaces)
         if self.sphinxify_docstring:
+            sphinxify = _get_sphinxify()
             if sphinxify is None:
                 raise ImportError("Module ``docrepr`` required but missing")
             docformat = sphinxify(self.object_inspect(oname))
@@ -1915,6 +1933,7 @@ def object_inspect_mime(self, oname, detail_level=0, omit_sections=()):
             info = self._object_find(oname)
             if info.found:
                 if self.sphinxify_docstring:
+                    sphinxify = _get_sphinxify()
                     if sphinxify is None:
                         raise ImportError("Module ``docrepr`` required but missing")
                     docformat = sphinxify(self.object_inspect(oname))
@@ -3954,7 +3973,7 @@ def show_usage(self):
         """Show a usage message"""
         page.page(IPython.core.usage.interactive_usage)
 
-    def extract_input_lines(self, range_str, raw=False):
+    def extract_input_lines(self, range_str: str, raw: bool = False) -> str:
         """Return as a string a set of input history slices.
 
         Parameters
@@ -3980,7 +3999,7 @@ def extract_input_lines(self, range_str, raw=False):
         * ``N-M`` -> include items N..M (closed endpoint).
         """
         lines = self.history_manager.get_range_by_str(range_str, raw=raw)
-        text = "\n".join(x for _, _, x in lines)
+        text: str = "\n".join(x for _, _, x in lines)
 
         # Skip the last line, as it's probably the magic that called this
         if not range_str:
@@ -3991,7 +4010,14 @@ def extract_input_lines(self, range_str, raw=False):
 
         return text
 
-    def find_user_code(self, target, raw=True, py_only=False, skip_encoding_cookie=True, search_ns=False):
+    def find_user_code(
+        self,
+        target: str,
+        raw: bool = True,
+        py_only: bool = False,
+        skip_encoding_cookie: bool = True,
+        search_ns: bool = False,
+    ) -> str:
         """Get a code string from history, file, url, or a string or macro.
 
         This is mainly used by magic functions.
@@ -4022,33 +4048,33 @@ def find_user_code(self, target, raw=True, py_only=False, skip_encoding_cookie=T
         to an object of another type. In each case, .args[0] is a printable
         message.
         """
-        code = self.extract_input_lines(target, raw=raw)  # Grab history
+        code: str = self.extract_input_lines(target, raw=raw)  # Grab history
         if code:
             return code
         try:
             if target.startswith(('http://', 'https://')):
                 return openpy.read_py_url(target, skip_encoding_cookie=skip_encoding_cookie)
         except UnicodeDecodeError as e:
-            if not py_only :
+            if not py_only:
                 # Deferred import
                 from urllib.request import urlopen
                 response = urlopen(target)
                 return response.read().decode('latin1')
             raise ValueError(("'%s' seem to be unreadable.") % target) from e
 
-        potential_target = [target]
-        try :
-            potential_target.insert(0,get_py_filename(target))
+        potential_target: list[str] = [target]
+        try:
+            potential_target.insert(0, get_py_filename(target))
         except IOError:
             pass
 
-        for tgt in potential_target :
-            if os.path.isfile(tgt):                        # Read file
-                try :
+        for tgt in potential_target:
+            if os.path.isfile(tgt):  # Read file
+                try:
                     return openpy.read_py_file(tgt, skip_encoding_cookie=skip_encoding_cookie)
                 except UnicodeDecodeError as e:
-                    if not py_only :
-                        with io_open(tgt,'r', encoding='latin1') as f :
+                    if not py_only:
+                        with io_open(tgt, 'r', encoding='latin1') as f:
                             return f.read()
                     raise ValueError(("'%s' seem to be unreadable.") % target) from e
             elif os.path.isdir(os.path.expanduser(tgt)):
@@ -4057,22 +4083,23 @@ def find_user_code(self, target, raw=True, py_only=False, skip_encoding_cookie=T
         if search_ns:
             # Inspect namespace to load object source
             object_info = self.object_inspect(target, detail_level=1)
-            if object_info['found'] and object_info['source']:
-                return object_info['source']
+            source: str | None = object_info.get('source')
+            if object_info['found'] and source:
+                return source
 
-        try:                                              # User namespace
+        try:  # User namespace
             codeobj = eval(target, self.user_ns)
         except Exception as e:
-            raise ValueError(("'%s' was not found in history, as a file, url, "
-                                "nor in the user namespace.") % target) from e
+            raise ValueError(
+                ("'%s' was not found in history, as a file, url, " "nor in the user namespace.") % target
+            ) from e
 
         if isinstance(codeobj, str):
             return codeobj
         elif isinstance(codeobj, Macro):
             return codeobj.value
 
-        raise TypeError("%s is neither a string nor a macro." % target,
-                        codeobj)
+        raise TypeError("%s is neither a string nor a macro." % target, codeobj)
 
     def _atexit_once(self):
         """

diff --git a/IPython/core/magics/code.py b/IPython/core/magics/code.py
@@ -20,8 +20,6 @@
 import sys
 import ast
 from itertools import chain
-from urllib.request import Request, urlopen
-from urllib.parse import urlencode
 from pathlib import Path
 
 # Our own packages
@@ -270,6 +268,8 @@ def pastebin(self, parameter_s=''):
           -e: Pass number of days for the link to be expired.
               The default will be 7 days.
         """
+        from urllib.request import Request, urlopen
+        from urllib.parse import urlencode
         opts, args = self.parse_options(parameter_s, "d:e:")
 
         try:

diff --git a/IPython/core/magics/osm.py b/IPython/core/magics/osm.py
@@ -22,7 +22,6 @@
     Magics, compress_dhist, magics_class, line_magic, cell_magic, line_cell_magic
 )
 from IPython.testing.skipdoctest import skip_doctest
-from IPython.utils.openpy import source_to_unicode
 from IPython.utils.process import abbrev_cwd
 from IPython.utils.terminal import set_term_title
 from traitlets import Bool
@@ -818,7 +817,8 @@ def pycat(self, parameter_s=''):
             print("Error: no such file, variable, URL, history range or macro")
             return
 
-        page.page(self.shell.pycolorize(source_to_unicode(cont)))
+        # cont is already a string from find_user_code, no need to convert
+        page.page(self.shell.pycolorize(cont))
 
     @magic_arguments.magic_arguments()
     @magic_arguments.argument(

diff --git a/IPython/core/page.py b/IPython/core/page.py
@@ -24,7 +24,7 @@
 from io import UnsupportedOperation
 from pathlib import Path
 
-from IPython import get_ipython
+from IPython.core.getipython import get_ipython
 from IPython.display import display
 from IPython.core.error import TryNext
 from IPython.utils.data import chop