Problem:
Some language servers (e.g., rust-analyzer, texlab) are desynced when
the user deletes the entire contents of the buffer. This is due to the
discrepancy between how nvim computes diff and how nvim treats empty
buffer.
* diff: If the buffer became empty, then the diff includes the last
line's eol.
* empty buffer: Even if the buffer is empty, nvim regards it as having
a single empty line with eol.
Solution:
Add special case for diff computation when the buffer becomes empty so
that it does not include the eol of the last line.
Specifically, functions that are run in the context of the test runner
are put in module `test/testutil.lua` while the functions that are run
in the context of the test session are put in
`test/functional/testnvim.lua`.
Closes https://github.com/neovim/neovim/issues/27004.
`nvim_(get|set)_option_value` pick the current buffer / window by default for buffer-local/window-local (but not global-local) options. So specifying `buf = 0` or `win = 0` in opts is unnecessary for those options. This PR removes those to reduce code clutter.
Closes#16624
Fixes two issues with aligning the start position and end position to
codepoints when calculating the start and end range.
When aligning the start position:
* use aligned byte index to calculate character index rather than
the unadjusted byte
When aligning the end position:
* do not adjust the end byte if it falls on a UTF-8 codepoint
* align byte to the first byte of the next codepoint rather than the
last byte of the current codepoint
* compute character character end range on the aligned byte index
This commit also adds additional test coverage, including multibyte operations
that previously failed before this commit.
* use codeunits/points instead of byte ranges when applicable
* take into account different file formats when computing range and
sending text (dos, unix, and mac supported)
* add tests of incremental sync
