diffs.nvim/doc/diffs.nvim.txt

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*diffs.nvim.txt* Syntax highlighting for diffs in Neovim
Author: Barrett Ruth <br.barrettruth@gmail.com>
License: MIT
==============================================================================
INTRODUCTION *diffs.nvim*
diffs.nvim adds syntax highlighting to diff views. It overlays language-aware
highlights on top of default diff highlighting in vim-fugitive and Neovim's
built-in diff mode.
Features: ~
- Syntax highlighting in |:Git| summary diffs and commit detail views
- Syntax highlighting in |:Gdiffsplit| / |:Gvdiffsplit| side-by-side diffs
- Background-only diff colors for any `&diff` buffer (vimdiff, diffthis, etc.)
- Vim syntax fallback for languages without a treesitter parser
- Blended diff background colors that preserve syntax visibility
- Optional diff prefix (`+`/`-`/` `) concealment
- Gutter (line number) highlighting
==============================================================================
REQUIREMENTS *diffs-requirements*
- Neovim 0.9.0+
- vim-fugitive (https://github.com/tpope/vim-fugitive) (optional, for unified
diff syntax highlighting in |:Git| and commit views)
- Treesitter parsers for languages you want highlighted
Note: The diff mode feature (background-only colors for |:diffthis|, vimdiff,
etc.) works without vim-fugitive.
==============================================================================
SETUP *diffs-setup*
Using lazy.nvim: >lua
{
'barrettruth/diffs.nvim',
dependencies = { 'tpope/vim-fugitive' },
opts = {},
}
<
The plugin works automatically with no configuration required. For
customization, see |diffs-config|.
==============================================================================
CONFIGURATION *diffs-config*
*diffs.Config*
Fields: ~
{debug} (boolean, default: false)
Enable debug logging to |:messages| with
`[diffs]` prefix.
{debounce_ms} (integer, default: 0)
Debounce delay in milliseconds for re-highlighting
after buffer changes. Lower values feel snappier
but use more CPU.
{hide_prefix} (boolean, default: false)
Hide diff prefixes (`+`/`-`/` `) using virtual
text overlay. Makes code appear without the
leading diff character. When `highlights.background`
is also enabled, the overlay inherits the line's
background color.
{treesitter} (table, default: see below)
Treesitter highlighting options.
See |diffs.TreesitterConfig| for fields.
{vim} (table, default: see below)
Vim syntax highlighting options (experimental).
See |diffs.VimConfig| for fields.
{highlights} (table, default: see below)
Controls which highlight features are enabled.
See |diffs.Highlights| for fields.
*diffs.TreesitterConfig*
Treesitter config fields: ~
{enabled} (boolean, default: true)
Apply treesitter syntax highlighting to code.
{max_lines} (integer, default: 500)
Skip treesitter highlighting for hunks larger than
this many lines. Prevents lag on massive diffs.
*diffs.VimConfig*
Vim config fields: ~
{enabled} (boolean, default: false)
Use vim syntax highlighting as fallback when no
treesitter parser is available for a language.
Creates a scratch buffer, sets the filetype, and
queries |synID()| per character to extract
highlight groups. Slower than treesitter but
covers languages without a TS parser installed.
{max_lines} (integer, default: 200)
Skip vim syntax highlighting for hunks larger than
this many lines. Lower than the treesitter default
due to the per-character cost of |synID()|.
*diffs.Highlights*
Highlights table fields: ~
{background} (boolean, default: true)
Apply background highlighting to `+`/`-` lines
using `DiffsAdd`/`DiffsDelete` groups (derived
from `DiffAdd`/`DiffDelete` backgrounds).
{gutter} (boolean, default: true)
Highlight line numbers with matching colors.
Only visible if line numbers are enabled.
Note: Header context (e.g., `@@ -10,3 +10,4 @@ func()`) is always
highlighted with treesitter when a parser is available.
Language detection uses Neovim's built-in |vim.filetype.match()| and
|vim.treesitter.language.get_lang()|. To customize filetype detection
or register treesitter parsers for custom filetypes, use
|vim.filetype.add()| and |vim.treesitter.language.register()|.
==============================================================================
API *diffs-api*
setup({opts}) *diffs.setup()*
Configure the plugin with `opts`.
Parameters: ~
{opts} (|diffs.Config|, optional) Configuration table.
attach({bufnr}) *diffs.attach()*
Manually attach highlighting to a buffer. Called automatically for
fugitive buffers via the `FileType fugitive` autocmd.
Parameters: ~
{bufnr} (integer, optional) Buffer number. Defaults to current buffer.
refresh({bufnr}) *diffs.refresh()*
Manually refresh highlighting for a buffer. Useful after external changes
or for debugging.
Parameters: ~
{bufnr} (integer, optional) Buffer number. Defaults to current buffer.
==============================================================================
IMPLEMENTATION *diffs-implementation*
Summary / commit detail views: ~
1. `FileType fugitive` or `FileType git` (for `fugitive://` buffers)
triggers |diffs.attach()|
2. The buffer is parsed to detect file headers (`M path/to/file`,
`diff --git a/... b/...`) and hunk headers (`@@ -10,3 +10,4 @@`)
3. For each hunk:
- Language is detected from the filename using |vim.filetype.match()|
- Diff prefixes (`+`/`-`/` `) are stripped from code lines
- Code is parsed with |vim.treesitter.get_string_parser()|
- If no treesitter parser and `vim.enabled`: vim syntax fallback via
scratch buffer and |synID()|
- Background extmarks (`DiffsAdd`/`DiffsDelete`) at priority 198
- `Normal` extmarks at priority 199 clear underlying diff foreground
- Syntax highlights are applied as extmarks at priority 200
- Conceal extmarks hide diff prefixes when `hide_prefix` is enabled
4. Re-highlighting occurs on `TextChanged` (debounced) and `Syntax` events
Diff mode views: ~
1. `OptionSet diff` detects when any window enters diff mode
2. All `&diff` windows in the tabpage receive a window-local 'winhighlight'
override that remaps `DiffAdd`/`DiffDelete`/`DiffChange`/`DiffText` to
background-only variants, allowing existing treesitter highlighting to
show through the diff colors
==============================================================================
KNOWN LIMITATIONS *diffs-limitations*
Syntax Highlighting Flash ~
*diffs-flash*
When opening a fugitive buffer, there is an unavoidable visual "flash" where
the buffer briefly shows fugitive's default diff highlighting before
diffs.nvim applies treesitter highlights.
This occurs because diffs.nvim hooks into the `FileType fugitive` event,
which fires after vim-fugitive has already painted the buffer. Even with
`debounce_ms = 0`, the re-painting goes through Neovim's event loop.
To minimize the flash, use a low debounce value: >lua
require('diffs').setup({
debounce_ms = 0,
})
<
==============================================================================
HIGHLIGHT GROUPS *diffs-highlights*
diffs.nvim defines custom highlight groups. Fugitive unified diff groups use
`default = true`, so colorschemes can override them. Diff mode groups are
always derived from the corresponding `Diff*` groups.
Fugitive unified diff highlights: ~
*DiffsAdd*
DiffsAdd Background for `+` lines. Derived by blending
`DiffAdd` background with `Normal` at 40% alpha.
*DiffsDelete*
DiffsDelete Background for `-` lines. Derived by blending
`DiffDelete` background with `Normal` at 40% alpha.
*DiffsAddNr*
DiffsAddNr Line number for `+` lines. Foreground from
`diffAdded`, background from `DiffsAdd`.
*DiffsDeleteNr*
DiffsDeleteNr Line number for `-` lines. Foreground from
`diffRemoved`, background from `DiffsDelete`.
Diff mode window highlights: ~
These are used for |winhighlight| remapping in `&diff` windows.
*DiffsDiffAdd*
DiffsDiffAdd Background-only. Derived from `DiffAdd` bg.
Treesitter provides foreground syntax highlighting.
*DiffsDiffDelete*
DiffsDiffDelete Foreground and background from `DiffDelete`.
Used for filler lines (`/////`) which have no real
code content to highlight.
*DiffsDiffChange*
DiffsDiffChange Background-only. Derived from `DiffChange` bg.
Treesitter provides foreground syntax highlighting.
*DiffsDiffText*
DiffsDiffText Background-only. Derived from `DiffText` bg.
Treesitter provides foreground syntax highlighting.
To customize these in your colorscheme: >lua
vim.api.nvim_set_hl(0, 'DiffsAdd', { bg = '#2e4a3a' })
vim.api.nvim_set_hl(0, 'DiffsDiffDelete', { link = 'DiffDelete' })
<
==============================================================================
HEALTH CHECK *diffs-health*
Run |:checkhealth| diffs to verify your setup.
Checks performed:
- Neovim version >= 0.9.0
- vim-fugitive is installed (optional)
==============================================================================
vim:tw=78:ts=8:ft=help:norl: