Fix a couple of edge cases, and update tests

Mostly when the match is super-short.
Ass type annotations,
run mypy on ptutils now.

.travis.yml

@@ -1,113 +1,114 b''
 # http://travis-ci.org/#!/ipython/ipython
 language: python
 os: linux
 
 addons:
   apt:
     packages:
       - graphviz
 
 python:
     - 3.6
 
 sudo: false
 
 env:
   global:
     - PATH=$TRAVIS_BUILD_DIR/pandoc:$PATH
 
 group: edge
 
 before_install:
   - |
     # install Python on macOS
     if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
       env | sort
       if ! which python$TRAVIS_PYTHON_VERSION; then
         HOMEBREW_NO_AUTO_UPDATE=1 brew tap minrk/homebrew-python-frameworks
         HOMEBREW_NO_AUTO_UPDATE=1 brew cask install python-framework-${TRAVIS_PYTHON_VERSION/./}
       fi
       python3 -m pip install virtualenv
       python3 -m virtualenv -p $(which python$TRAVIS_PYTHON_VERSION) ~/travis-env
       source ~/travis-env/bin/activate
     fi
   - python --version
 
 install:
   - pip install pip --upgrade
   - pip install setuptools --upgrade
   - pip install -e file://$PWD#egg=ipython[test] --upgrade
   - pip install trio curio --upgrade --upgrade-strategy eager
-  - pip install pytest 'matplotlib !=3.2.0'
+  - pip install pytest 'matplotlib !=3.2.0' mypy
   - pip install codecov check-manifest --upgrade
 
 script:
   - check-manifest
   - |
     if [[ "$TRAVIS_PYTHON_VERSION" == "nightly" ]]; then
        # on nightly fake parso known the grammar
        cp /home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/parso/python/grammar37.txt /home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/parso/python/grammar38.txt
     fi
   - cd /tmp && iptest --coverage xml && cd -
   - pytest IPython
+  - mypy --ignore-missing-imports -m IPython.terminal.ptutils
   # On the latest Python (on Linux) only, make sure that the docs build.
   - |
     if [[ "$TRAVIS_PYTHON_VERSION" == "3.7" ]] && [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
       pip install -r docs/requirements.txt
       python tools/fixup_whats_new_pr.py
       make -C docs/ html SPHINXOPTS="-W"
     fi
 
 after_success:
   - cp /tmp/ipy_coverage.xml ./
   - cp /tmp/.coverage ./
   - codecov
 
 matrix:
   include:
     - arch: amd64
       python: "3.7"
       dist: xenial
       sudo: true
     - arch: amd64
       python: "3.8"
       dist: xenial
       sudo: true
     - arch: amd64
       python: "nightly"
       dist: xenial
       sudo: true
     - arch: arm64
       python: "nightly"
       dist: bionic
       env: ARM64=True
       sudo: true
     - os: osx
       language: generic
       python: 3.6
       env: TRAVIS_PYTHON_VERSION=3.6
     - os: osx
       language: generic
       python: 3.7
       env: TRAVIS_PYTHON_VERSION=3.7
   allow_failures:
     - python: nightly
 
 before_deploy:
   - rm -rf dist/
   - python setup.py sdist
   - python setup.py bdist_wheel
 
 deploy:
   provider: releases
   api_key:
     secure: Y/Ae9tYs5aoBU8bDjN2YrwGG6tCbezj/h3Lcmtx8HQavSbBgXnhnZVRb2snOKD7auqnqjfT/7QMm4ZyKvaOEgyggGktKqEKYHC8KOZ7yp8I5/UMDtk6j9TnXpSqqBxPiud4MDV76SfRYEQiaDoG4tGGvSfPJ9KcNjKrNvSyyxns=
   file: dist/*
   file_glob: true
   skip_cleanup: true
   on:
     repo: ipython/ipython
     all_branches: true  # Backports are released from e.g. 5.x branch
     tags: true
     python: 3.6  # Any version should work, but we only need one
     condition: $TRAVIS_OS_NAME = "linux"

IPython/terminal/ptutils.py

@@ -1,190 +1,192 b''
 """prompt-toolkit utilities
 
 Everything in this module is a private API,
 not to be used outside IPython.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import unicodedata
 from wcwidth import wcwidth
 
 from IPython.core.completer import (
     provisionalcompleter, cursor_to_position,
     _deduplicate_completions)
 from prompt_toolkit.completion import Completer, Completion
 from prompt_toolkit.lexers import Lexer
 from prompt_toolkit.lexers import PygmentsLexer
 from prompt_toolkit.patch_stdout import patch_stdout
 
 import pygments.lexers as pygments_lexers
 import os
 
 _completion_sentinel = object()
 
-def _elide_point(string, *, min_elide=30):
+def _elide_point(string:str, *, min_elide=30)->str:
     """
     If a string is long enough, and has at least 3 dots,
     replace the middle part with ellipses.
 
     If a string naming a file is long enough, and has at least 3 slashes,
     replace the middle part with ellipses.
 
     If three consecutive dots, or two consecutive dots are encountered these are
     replaced by the equivalents HORIZONTAL ELLIPSIS or TWO DOT LEADER unicode
     equivalents
     """
     string = string.replace('...','\N{HORIZONTAL ELLIPSIS}')
     string = string.replace('..','\N{TWO DOT LEADER}')
     if len(string) < min_elide:
         return string
 
     object_parts = string.split('.')
     file_parts = string.split(os.sep)
     if file_parts[-1] == '':
         file_parts.pop()
 
     if len(object_parts) > 3:
         return '{}.{}\N{HORIZONTAL ELLIPSIS}{}.{}'.format(object_parts[0], object_parts[1][0], object_parts[-2][-1], object_parts[-1])
 
     elif len(file_parts) > 3:
         return ('{}' + os.sep + '{}\N{HORIZONTAL ELLIPSIS}{}' + os.sep + '{}').format(file_parts[0], file_parts[1][0], file_parts[-2][-1], file_parts[-1])
 
     return string
 
-def _elide_typed(string, typed, *, min_elide=30):
+def _elide_typed(string:str, typed:str, *, min_elide:int=30)->str:
     """
     Elide the middle of a long string if the beginning has already been typed.
     """
 
     if len(string) < min_elide:
         return string
     cut_how_much = len(typed)-3
+    if cut_how_much < 7:
+        return string
     if string.startswith(typed) and len(string)> len(typed):
         return f"{string[:3]}\N{HORIZONTAL ELLIPSIS}{string[cut_how_much:]}"
     return string
 
-def _elide(string, typed, min_elide=30):
+def _elide(string:str, typed:str, min_elide=30)->str:
     return _elide_typed(
         _elide_point(string, min_elide=min_elide),
         typed, min_elide=min_elide)
 
 
 
 def _adjust_completion_text_based_on_context(text, body, offset):
     if text.endswith('=') and len(body) > offset and body[offset] == '=':
         return text[:-1]
     else:
         return text
 
 
 class IPythonPTCompleter(Completer):
     """Adaptor to provide IPython completions to prompt_toolkit"""
     def __init__(self, ipy_completer=None, shell=None):
         if shell is None and ipy_completer is None:
             raise TypeError("Please pass shell=an InteractiveShell instance.")
         self._ipy_completer = ipy_completer
         self.shell = shell
 
     @property
     def ipy_completer(self):
         if self._ipy_completer:
             return self._ipy_completer
         else:
             return self.shell.Completer
 
     def get_completions(self, document, complete_event):
         if not document.current_line.strip():
             return
         # Some bits of our completion system may print stuff (e.g. if a module
         # is imported). This context manager ensures that doesn't interfere with
         # the prompt.
 
         with patch_stdout(), provisionalcompleter():
             body = document.text
             cursor_row = document.cursor_position_row
             cursor_col = document.cursor_position_col
             cursor_position = document.cursor_position
             offset = cursor_to_position(body, cursor_row, cursor_col)
             try:
                 yield from self._get_completions(body, offset, cursor_position, self.ipy_completer)
             except Exception as e:
                 from traceback import print_tb
                 print_tb(e)
 
     @staticmethod
     def _get_completions(body, offset, cursor_position, ipyc):
         """
         Private equivalent of get_completions() use only for unit_testing.
         """
         debug = getattr(ipyc, 'debug', False)
         completions = _deduplicate_completions(
             body, ipyc.completions(body, offset))
         for c in completions:
             if not c.text:
                 # Guard against completion machinery giving us an empty string.
                 continue
             text = unicodedata.normalize('NFC', c.text)
             # When the first character of the completion has a zero length,
             # then it's probably a decomposed unicode character. E.g. caused by
             # the "\dot" completion. Try to compose again with the previous
             # character.
             if wcwidth(text[0]) == 0:
                 if cursor_position + c.start > 0:
                     char_before = body[c.start - 1]
                     fixed_text = unicodedata.normalize(
                         'NFC', char_before + text)
 
                     # Yield the modified completion instead, if this worked.
                     if wcwidth(text[0:1]) == 1:
                         yield Completion(fixed_text, start_position=c.start - offset - 1)
                         continue
 
             # TODO: Use Jedi to determine meta_text
             # (Jedi currently has a bug that results in incorrect information.)
             # meta_text = ''
             # yield Completion(m, start_position=start_pos,
             #                  display_meta=meta_text)
             display_text = c.text
 
             adjusted_text = _adjust_completion_text_based_on_context(c.text, body, offset)
             if c.type == 'function':
                 yield Completion(adjusted_text, start_position=c.start - offset, display=_elide(display_text+'()', body[c.start:c.end]), display_meta=c.type+c.signature)
             else:
                 yield Completion(adjusted_text, start_position=c.start - offset, display=_elide(display_text,  body[c.start:c.end]), display_meta=c.type)
 
 class IPythonPTLexer(Lexer):
     """
     Wrapper around PythonLexer and BashLexer.
     """
     def __init__(self):
         l = pygments_lexers
         self.python_lexer = PygmentsLexer(l.Python3Lexer)
         self.shell_lexer = PygmentsLexer(l.BashLexer)
 
         self.magic_lexers = {
             'HTML': PygmentsLexer(l.HtmlLexer),
             'html': PygmentsLexer(l.HtmlLexer),
             'javascript': PygmentsLexer(l.JavascriptLexer),
             'js': PygmentsLexer(l.JavascriptLexer),
             'perl': PygmentsLexer(l.PerlLexer),
             'ruby': PygmentsLexer(l.RubyLexer),
             'latex': PygmentsLexer(l.TexLexer),
         }
 
     def lex_document(self, document):
         text = document.text.lstrip()
 
         lexer = self.python_lexer
 
         if text.startswith('!') or text.startswith('%%bash'):
             lexer = self.shell_lexer
 
         elif text.startswith('%%'):
             for magic, l in self.magic_lexers.items():
                 if text.startswith('%%' + magic):
                     lexer = l
                     break
 
         return lexer.lex_document(document)

IPython/terminal/tests/test_interactivshell.py

@@ -1,175 +1,193 b''
 # -*- coding: utf-8 -*-
 """Tests for the TerminalInteractiveShell and related pieces."""
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import sys
 import unittest
 import os
 
 from IPython.core.inputtransformer import InputTransformer
 from IPython.testing import tools as tt
 from IPython.utils.capture import capture_output
 
 from IPython.terminal.ptutils import _elide, _adjust_completion_text_based_on_context
 import nose.tools as nt
 
 class TestElide(unittest.TestCase):
 
     def test_elide(self):
-        _elide('concatenate((a1, a2, ...), axis') # do not raise
-        _elide('concatenate((a1, a2, ..), . axis') # do not raise
-        nt.assert_equal(_elide('aaaa.bbbb.ccccc.dddddd.eeeee.fffff.gggggg.hhhhhh'), 'aaaa.b…g.hhhhhh')
-        
+        _elide('concatenate((a1, a2, ...), axis', '') # do not raise
+        _elide('concatenate((a1, a2, ..), . axis', '') # do not raise
+        nt.assert_equal(_elide('aaaa.bbbb.ccccc.dddddd.eeeee.fffff.gggggg.hhhhhh',''), 'aaaa.b…g.hhhhhh')
+
         test_string = os.sep.join(['', 10*'a', 10*'b', 10*'c', ''])
         expect_stirng = os.sep + 'a' + '\N{HORIZONTAL ELLIPSIS}' + 'b' + os.sep + 10*'c'
-        nt.assert_equal(_elide(test_string), expect_stirng)
-
+        nt.assert_equal(_elide(test_string, ''), expect_stirng)
+
+    def test_elide_typed_normal(self):
+        nt.assert_equal(_elide('the quick brown fox jumped over the lazy dog', 'the quick brown fox', min_elide=10), 'the…fox jumped over the lazy dog')
+
+
+    def test_elide_typed_short_match(self):
+        """
+        if the match is too short we don't elide.
+        avoid the "the...the"
+        """
+        nt.assert_equal(_elide('the quick brown fox jumped over the lazy dog', 'the', min_elide=10), 'the quick brown fox jumped over the lazy dog')
+
+    def test_elide_typed_no_match(self):
+        """
+        if the match is too short we don't elide.
+        avoid the "the...the"
+        """
+        # here we typed red instead of brown
+        nt.assert_equal(_elide('the quick brown fox jumped over the lazy dog', 'the quick red fox', min_elide=10), 'the quick brown fox jumped over the lazy dog')
 
 class TestContextAwareCompletion(unittest.TestCase):
 
     def test_adjust_completion_text_based_on_context(self):
         # Adjusted case
         nt.assert_equal(_adjust_completion_text_based_on_context('arg1=', 'func1(a=)', 7), 'arg1')
 
         # Untouched cases
         nt.assert_equal(_adjust_completion_text_based_on_context('arg1=', 'func1(a)', 7), 'arg1=')
         nt.assert_equal(_adjust_completion_text_based_on_context('arg1=', 'func1(a', 7), 'arg1=')
         nt.assert_equal(_adjust_completion_text_based_on_context('%magic', 'func1(a=)', 7), '%magic')
         nt.assert_equal(_adjust_completion_text_based_on_context('func2', 'func1(a=)', 7), 'func2')
 
 # Decorator for interaction loop tests -----------------------------------------
 
 class mock_input_helper(object):
     """Machinery for tests of the main interact loop.
 
     Used by the mock_input decorator.
     """
     def __init__(self, testgen):
         self.testgen = testgen
         self.exception = None
         self.ip = get_ipython()
 
     def __enter__(self):
         self.orig_prompt_for_code = self.ip.prompt_for_code
         self.ip.prompt_for_code = self.fake_input
         return self
 
     def __exit__(self, etype, value, tb):
         self.ip.prompt_for_code = self.orig_prompt_for_code
 
     def fake_input(self):
         try:
             return next(self.testgen)
         except StopIteration:
             self.ip.keep_running = False
             return u''
         except:
             self.exception = sys.exc_info()
             self.ip.keep_running = False
             return u''
 
 def mock_input(testfunc):
     """Decorator for tests of the main interact loop.
 
     Write the test as a generator, yield-ing the input strings, which IPython
     will see as if they were typed in at the prompt.
     """
     def test_method(self):
         testgen = testfunc(self)
         with mock_input_helper(testgen) as mih:
             mih.ip.interact()
 
         if mih.exception is not None:
             # Re-raise captured exception
             etype, value, tb = mih.exception
             import traceback
             traceback.print_tb(tb, file=sys.stdout)
             del tb  # Avoid reference loop
             raise value
 
     return test_method
 
 # Test classes -----------------------------------------------------------------
 
 class InteractiveShellTestCase(unittest.TestCase):
     def rl_hist_entries(self, rl, n):
         """Get last n readline history entries as a list"""
         return [rl.get_history_item(rl.get_current_history_length() - x)
                 for x in range(n - 1, -1, -1)]
     
     @mock_input
     def test_inputtransformer_syntaxerror(self):
         ip = get_ipython()
         ip.input_transformers_post.append(syntax_error_transformer)
 
         try:
             #raise Exception
             with tt.AssertPrints('4', suppress=False):
                 yield u'print(2*2)'
 
             with tt.AssertPrints('SyntaxError: input contains', suppress=False):
                 yield u'print(2345) # syntaxerror'
 
             with tt.AssertPrints('16', suppress=False):
                 yield u'print(4*4)'
 
         finally:
             ip.input_transformers_post.remove(syntax_error_transformer)
 
     def test_plain_text_only(self):
         ip = get_ipython()
         formatter = ip.display_formatter
         assert formatter.active_types == ['text/plain']
         assert not formatter.ipython_display_formatter.enabled
 
         class Test(object):
             def __repr__(self):
                 return "<Test %i>" % id(self)
 
             def _repr_html_(self):
                 return '<html>'
 
         # verify that HTML repr isn't computed
         obj = Test()
         data, _ = formatter.format(obj)
         self.assertEqual(data, {'text/plain': repr(obj)})
 
         class Test2(Test):
             def _ipython_display_(self):
                 from IPython.display import display
                 display('<custom>')
 
         # verify that _ipython_display_ shortcut isn't called
         obj = Test2()
         with capture_output() as captured:
             data, _ = formatter.format(obj)
 
         self.assertEqual(data, {'text/plain': repr(obj)})
         assert captured.stdout == ''
 
 def syntax_error_transformer(lines):
     """Transformer that throws SyntaxError if 'syntaxerror' is in the code."""
     for line in lines:
         pos = line.find('syntaxerror')
         if pos >= 0:
             e = SyntaxError('input contains "syntaxerror"')
             e.text = line
             e.offset = pos + 1
             raise e
     return lines
 
 
 class TerminalMagicsTestCase(unittest.TestCase):
     def test_paste_magics_blankline(self):
         """Test that code with a blank line doesn't get split (gh-3246)."""
         ip = get_ipython()
         s = ('def pasted_func(a):\n'
              '    b = a+1\n'
              '\n'
              '    return b')
         
         tm = ip.magics_manager.registry['TerminalMagics']
         tm.store_or_execute(s, name=None)
         
         self.assertEqual(ip.user_ns['pasted_func'](54), 55)