Undeprecate autoindent

Autoindent is usefull for some extension that want to use ipython as a
subprocess, so un-deprecated it.

docs/source/whatsnew/pr/re-autoindent.rst

@@ -0,0 +1,2 b''
+The autoindent feature that was deprecated in 5.x was re-enabled and
+un-deprecated in :ghpull:`11257`

IPython/core/interactiveshell.py

@@ -250,8 +250,7 b' class InteractiveShell(SingletonConfigurable):'
         objects are automatically called (even if no arguments are present).
         """
     ).tag(config=True)
-    # TODO: remove all autoindent logic and put into frontends.
-    # We can't do this yet because even runlines uses the autoindent.
+
     autoindent = Bool(True, help=
         """
         Autoindent IPython code entered interactively.

IPython/terminal/magics.py

@@ -82,8 +82,6 b' class TerminalMagics(Magics):'
     @line_magic
     def autoindent(self, parameter_s = ''):
         """Toggle autoindent on/off (deprecated)"""
-        print("%autoindent is deprecated since IPython 5: you can now paste "
-              "multiple lines without turning autoindentation off.")
         self.shell.set_autoindent()
         print("Automatic indentation is:",['OFF','ON'][self.shell.autoindent])
 

IPython/terminal/shortcuts.py

@@ -112,13 +112,19 b' def newline_or_execute_outer(shell):'
         if not (d.on_last_line or
                 d.cursor_position_row >= d.line_count - d.empty_line_count_at_the_end()
                 ):
-            b.insert_text('\n' + (' ' * (indent or 0)))
+            if shell.autoindent:
+                b.insert_text('\n' + (' ' * (indent or 0)))
+            else:
+                b.insert_text('\n')
             return
 
         if (status != 'incomplete') and b.accept_handler:
             b.validate_and_handle()
         else:
-            b.insert_text('\n' + (' ' * (indent or 0)))
+            if shell.autoindent:
+                b.insert_text('\n' + (' ' * (indent or 0)))
+            else:
+                b.insert_text('\n')
     return newline_or_execute
 
 

docs/source/config/intro.rst

@@ -67,7 +67,6 b' Example config file'
         'mycode.py',
         'fancy.ipy'
     ]
-    c.InteractiveShell.autoindent = True
     c.InteractiveShell.colors = 'LightBG'
     c.InteractiveShell.confirm_exit = False
     c.InteractiveShell.editor = 'nano'

docs/source/interactive/tutorial.rst

@@ -146,7 +146,7 b' The built-in magics include:'
   :magic:`macro`, :magic:`recall`, etc.
 
 - Functions which affect the shell: :magic:`colors`, :magic:`xmode`,
-  :magic:`autoindent`, :magic:`automagic`, etc.
+  :magic:`automagic`, etc.
 
 - Other functions such as :magic:`reset`, :magic:`timeit`,
   :cellmagic:`writefile`, :magic:`load`, or :magic:`paste`.