Completion requests with column positions greater than the line length don't work (LSP implementation issue)

[w0rp]

The LSP protocol document says that character values for the position, used for methods like textDocument/completion should accept values greater than the length of a line. https://github.com/Microsoft/language-server-protocol/blob/master/protocol.md#position

* If the character value is greater than the line length it defaults back to the
* line length.

However, validation in jedi causes an exception to be thrown.

558.368137 on 1: Dropping message '2017-11-21 17:22:37,470 UTC - ERROR - jsonrpc.manager - API Exception: {'type': 'ValueError', 'args': ('`column` parameter is not in a valid range.',), 'message': '`column` parameter is not in a valid range.'}
Traceback (most recent call last):
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/jsonrpc/manager.py", line 112, in _get_responses
    result = method(*request.args, **request.kwargs)
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/language_server.py", line 66, in wrapped
    return func(*args, **kwargs)
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/python_ls.py", line 138, in m_text_document__completion
    return self.completions(textDocument['uri'], position)
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/python_ls.py", line 68, in completions
    position=position
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/_utils.py", line 52, in race_hooks
    for impl, result in pool.imap_unordered(_apply, impls, chunksize=1):
  File "/usr/lib/python3.6/multiprocessing/pool.py", line 735, in next
    raise value
  File "/usr/lib/python3.6/multiprocessing/pool.py", line 119, in worker
    result = (True, func(*args, **kwds))
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/_utils.py", line 47, in _apply
    return impl, impl.function(**kwargs)
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/plugins/jedi_completion.py", line 12, in pyls_completions
    definitions = document.jedi_script(position).completions()
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/pyls/workspace.py", line 265, in jedi_script
    return jedi.Script(**kwargs)
  File "/home/w0rp/Downloads/python-ls-project/ve/lib/python3.6/site-packages/jedi/api/__init__.py", line 102, in __init__
    raise ValueError('`column` parameter is not in a valid range.')
ValueError: `column` parameter is not in a valid range.

The ideal way to fix this would be to remove the validation in jedi, and make it use column = min(column, line_len) instead.

[w0rp]

The jedi maintainer refuses to fix this, so this issue will have to be handled here.

[gatesn]

I agree it makes sense to fix here as it’s a peculiarity of the protocol. Jedi is not incorrect to throw in this case.

…

________________________________ From: w0rp <notifications@github.com> Sent: Wednesday, November 22, 2017 8:34:55 PM To: palantir/python-language-server Cc: Subscribed Subject: Re: [palantir/python-language-server] Completion requests with column positions greater than the line length don't work (LSP implementation issue) (#193) The jedi maintainer refuses to fix this, so this issue will have to be handled here. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub<#193 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AB1rdB5-bWwNIfkIROeD9VLMiN6JnOmoks5s5IVvgaJpZM4QmN1y>.

[w0rp]

Okay.

[bbenne10]

I have forked to solve this issue with a PR, but I'm unsure how I might be able to get the current line's length from within PythonLanguageServer.completions. It looks easy enough to add a bare try/except in here, but given @w0rp's original comment regarding the intended behavior, this doesn't feel right. Is there a way to do this? Or is this just more difficult that I initially believed?

[gatesn]

I think you want to find the line under the position using the Document class