Merge pull request #12801 from Carreau/wn-80

some updates on 8.0

docs/source/whatsnew/development.rst

@@ -1,104 +1,145 b''
 =====================
  Development version
 =====================
 
 This document describes in-flight development work.
 
 .. warning::
 
     Please do not edit this file by hand (doing so will likely cause merge
     conflicts for other Pull Requests). Instead, create a new file in the
     `docs/source/whatsnew/pr` folder
 
 
 Released .... ...., 2019
 
 
 Need to be updated:
 
 .. toctree::
    :maxdepth: 2
    :glob:
 
    pr/*
 
+IPython 8.0 is bringing a number of new features and improvements to both the
+user of the terminal and of the kernel via Jupyter. The removal of compatibility
+with older version of Python is also the opportunity to do a couple of
+performance improvement in particular with respect to startup time.
+
+The main change in IPython 8.0 is the integration of the ``stack_data`` package;
+which provide smarter information in traceback; in particular it will highlight
+the AST node where an error occurs which can help to quickly narrow down errors.
+
+For example in the following snippet::
+
+    def foo(i):
+        x = [[[0]]]
+        return x[0][i][0]
+
+
+    def bar():
+        return foo(0) + foo(
+            1
+        ) + foo(2)
+
+
+Calling ``bar()`` would raise an ``IndexError`` on the return line of ``foo``,
+IPython 8.0 is capable of telling you, where the index error occurs::
+
+    return x[0][i][0]
+                ^
+
+To prepare for Python 3.10 we have also started working on removing reliance and
+any dependency that is not Python 3.10 compatible; that include migrating our
+test suite to Pytest, and starting to remove nose.
+
+We are also removing support for Python 3.6 allowing internal code to use more
+efficient ``pathlib``, and make better use of type annotations.
+
+The completer has also seen significant updates and make use of newer Jedi API
+offering faster and more reliable tab completion.
+
+For the terminal users this also enable the auto-suggestion feature, described
+below, which show "ghost text" ahead of your cursor you can accept without
+having to press the tab key or ask the completer to suggest completions.
 
 
 Autosuggestion is a very useful feature available in `fish <https://fishshell.com/>`__, `zsh <https://en.wikipedia.org/wiki/Z_shell>`__, and `prompt-toolkit <https://python-prompt-toolkit.readthedocs.io/en/master/pages/asking_for_input.html#auto-suggestion>`__.
 
 `Ptpython <https://github.com/prompt-toolkit/ptpython#ptpython>`__ allows users to enable this feature in
 `ptpython/config.py <https://github.com/prompt-toolkit/ptpython/blob/master/examples/ptpython_config/config.py#L90>`__.
 
 This feature allows users to accept autosuggestions with ctrl e, ctrl f,
 or right arrow as described below.
 
 1. Start ipython
 
 .. image:: ../_images/auto_suggest_prompt_no_text.png
 
 2. Run ``print("hello")``
 
 .. image:: ../_images/auto_suggest_print_hello_suggest.png
 
 3. Press p to see the autosuggestion
 
 .. image:: ../_images/auto_suggest_print_hello_suggest.png
 
 4. Press ctrl f, or ctrl e, or right arrow to accept the suggestion
 
 .. image:: ../_images/auto_suggest_print_hello.png
 
 You can also complete word by word:
 
 1. Run ``def say_hello(): print("hello")``
 
 .. image:: ../_images/auto_suggest_second_prompt.png
 
 2. Press d to see the autosuggestion
 
 .. image:: ../_images/audo_suggest_d_phantom.png
 
 3. Press alt f to accept the first word of the suggestion
 
 .. image:: ../_images/auto_suggest_def_phantom.png
 
 Importantly, this feature does not interfere with tab completion:
 
 1. After running ``def say_hello(): print("hello")``, press d
 
 .. image:: ../_images/audo_suggest_d_phantom.png
 
 2. Press Tab to start tab completion
 
 .. image:: ../_images/auto_suggest_d_completions.png
 
 3A. Press Tab again to select the first option
 
 .. image:: ../_images/auto_suggest_def_completions.png
 
 3B. Press alt f to accept to accept the first word of the suggestion
 
 .. image:: ../_images/auto_suggest_def_phantom.png
 
 3C. Press ctrl f or ctrl e to accept the entire suggestion
 
 .. image:: ../_images/auto_suggest_match_parens.png
 
 To install a version of ipython with autosuggestions enabled, run:
 
 ``pip install git+https://github.com/mskar/ipython@auto_suggest``
 
 Currently, autosuggestions are only shown in the emacs or vi insert editing modes:
 
 - The ctrl e, ctrl f, and alt f shortcuts work by default in emacs mode.
 - To use these shortcuts in vi insert mode, you will have to create `custom keybindings in your config.py <https://github.com/mskar/setup/commit/2892fcee46f9f80ef7788f0749edc99daccc52f4/>`__.
 
 .. DO NOT EDIT THIS LINE BEFORE RELEASE. FEATURE INSERTION POINT.
 
 As a reminder, IPython master has diverged from the 7.x branch, thus master may
 have more feature and API changes.
 
 Backwards incompatible changes
 ------------------------------
 
 .. DO NOT EDIT THIS LINE BEFORE RELEASE. INCOMPAT INSERTION POINT.