Bring fully asynchronous completion by polling for completions with a timer
then calling completefunc once the completions are ready. Use the start column
returned by the server in completefunc. Immediately display the last completion
on the TextChangedI event to prevent the popup menu disappearing while waiting
for the completions. Handle the TextChangedI event not being triggered while
the completion menu is open by closing the menu when inserting a character
through the InsertCharPre event, and when deleting a character on the <BS> and
<C-h> keys.
Use the timers feature to display diagnostics asynchronously instead of waiting
for an autocommand to trigger.
Increase Vim version requirement to 7.4.1578.
Drop the CursorHold and CursorHoldI autocommands.
Parse buffer on the TextChanged autocommand instead of CursorMoved.
[READY] Improve reparse requirement on BufEnter event
When opening a file, Vim triggers the `BufRead` event then the `BufEnter` one. By setting the `s:previous_allowed_buffer_number` variable in `s:AllowedToCompleteInBuffer`, we avoid a reparse on `BufEnter` after parsing the buffer on `BufRead`. This reduces the number of `BufferVisit` and `FileReadyToParse` requests sent to the server by one when opening a file.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/valloric/youcompleteme/2644)
<!-- Reviewable:end -->
Considering that a buffer won't be parsed if no filetype is set and that it's
already parsed if the filetype is set when reading a buffer, there is no point
in parsing a buffer on the BufRead event.
When both versions are available, we prefer Python 3 over Python 2:
- faster startup (no monkey-patching from python-future);
- better Windows support (e.g. temporary paths are not returned in all
lowercase);
- Python 2 support will eventually be dropped.
[READY] Rely on connect timeout instead of checking that the server is alive
Currently, we always check that the ycmd process is up (with the `IsServerAlive` method) before sending a request. Without this check, each request could block Vim until a `NewConnectionError` exception is raised if the server crashed. This is the case on Windows where it takes ~1s before the exception is raised which makes Vim unusable. However, even with this check, Vim may still be blocked in the following cases:
- the server crashes just after the check but before sending the request;
- the server is up but unresponsive (e.g. its port is closed).
To avoid both cases, we instead use [the connect timeout parameter from Requests](http://docs.python-requests.org/en/master/user/advanced/?highlight=connect%20timeout#timeouts) and set it to a duration sufficiently short (10 ms) that the blocking can't be noticed by the user. Since the server is supposed to run locally (this is what YCM is designed for), 10ms is largely enough to establish a connection.
The `IsServerAlive` check is removed almost everywhere except in `OnFileReadyToParse` because we still want to notify the user if the server crashed.
This change makes it possible to not have to [wait for the server to be healthy before sending asynchronous requests](https://github.com/Valloric/YouCompleteMe/blob/master/python/ycm/client/base_request.py#L137-L138). This will dramatically improve startup time (see issue #2085) and fixes#2071. Next PR once this one is merged.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/valloric/youcompleteme/2514)
<!-- Reviewable:end -->
Vim automatically adds a space between strings when concatenating them
without the dot operator. This is not obvious so we always use the dot
operator.
Minor coding style changes when writing statements on multiple lines to
be more consistent.
Send the request as the unloaded buffer instead of the current buffer
for the BufferUnload event notification. This fixes the issue where
the filetype of the current buffer is not the same as the unloaded
buffer one, making the ycmd server uses the wrong completer when
handling the request.
Long and personal experience, when TextChangedI gets used, YCM seems
to perform better, diagnostics will trigger much less frequently at
inappropriate occasions, even less with whitespace agnostic triggers,
if I recall correctly...
When selecting candidates during completion, Vim jumps to the preview
window (if enabled) and jumps back to the actual buffer, triggering
twice the BufEnter autocommand event. This results in YCM sending
two BufferVisit and one FileReadyToParse event notifications to
ycmd, which is completely unnecessary since the current buffer
did not change. We improve this by only sending these events when the
entered buffer allowed to be completed has changed.
Open the quickfix window to full width at the bottom of the screen with
its height set to fit all entries. This behavior can be overridden by
using the YcmQuickFixOpened autocommand.
Add a new section for autocommands in the documentation.
Update GoTo and ReplaceChunks tests.
Moved File parse request handling and diagnostic extraction flow into
python to simplify flow and allow easier addition of new parse request
handlers such as semantic highlighter.
Refactored base_test to patch separate vimsupport functions instead of
the whole module, and interfering the test results afterwards.
Added new tests for diagnostic sign place/unplace and error/warning
count extraction API.
