refactor(highlight): unified per-line extmark builder (#144)

## Problem

`highlight_hunk` applied DiffsClear extmarks across 5 scattered sites
with
ad-hoc column arithmetic. This fragmentation produced the 1-column
DiffsClear
gap on email-quoted body context lines (#142 issue 1). A redundant
`highlight_hunk_vim_syntax` function duplicated the inline vim syntax
path,
and the deferred pass in init.lua double-called it, creating duplicate
scratch
buffers and extmarks.

## Solution

Reorganize `highlight_hunk` into two clean phases:

- **Phase 1** — multi-line syntax computation (treesitter, vim syntax,
diff
grammar, header context text). Sets syntax extmarks only, no DiffsClear.
- **Phase 2** — per-line chrome (DiffsClear, backgrounds, gutter,
overlays,
  intra-line). All non-syntax extmarks consolidated in one pass.

Hoist `new_code` to function scope (needed by `highlight_text` outside
the
`use_ts` block). Hoist `at_raw_line` so Phase 1d and Phase 2b share one
`nvim_buf_get_lines` call.

Delete `highlight_hunk_vim_syntax` (redundant with inline path). Remove
the
double-call from the deferred pass in init.lua.

Extend body prefix DiffsClear `end_col` from `qw` to `pw + qw`, fixing
the
1-column gap where native treesitter background bled through on context
lines
in email-quoted diffs (#142 issue 1).

### Email-quoted diff support

The parser now strips `> ` (and `>> `, etc.) email quote prefixes before
pattern matching, enabling syntax highlighting for diffs embedded in
email
replies and `git-send-email` / sourcehut-style patch review threads.
Each hunk stores `quote_width` so the highlight pipeline can apply
`DiffsClear` at the correct column offsets to suppress native treesitter
on quoted regions.

Closes #141

### #142 status after this PR

| Sub-issue | Status |
|-----------|--------|
| 1. Col gap on context lines | Fixed |
| 2. Bare `>` context lines | Improved, edge case remains |
| 3. Diff prefix marker fg | Not addressed (follow-up) |
This commit is contained in:
Barrett Ruth 2026-03-05 09:01:22 -05:00 committed by GitHub
parent 7a3c4ea01e
commit 7106bcc291
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
11 changed files with 919 additions and 102 deletions

View file

@ -74,6 +74,7 @@ end
---@param col_offset integer
---@param covered_lines? table<integer, true>
---@param priorities diffs.PrioritiesConfig
---@param force_high_priority? boolean
---@return integer
local function highlight_treesitter(
bufnr,
@ -83,7 +84,8 @@ local function highlight_treesitter(
line_map,
col_offset,
covered_lines,
priorities
priorities,
force_high_priority
)
local code = table.concat(code_lines, '\n')
if code == '' then
@ -123,7 +125,9 @@ local function highlight_treesitter(
local buf_sc = sc + col_offset
local buf_ec = ec + col_offset
local priority = tree_lang == 'diff' and (tonumber(metadata.priority) or 100)
local meta_prio = tonumber(metadata.priority) or 100
local priority = tree_lang == 'diff'
and ((col_offset > 0 or force_high_priority) and (priorities.syntax + meta_prio - 100) or meta_prio)
or priorities.syntax
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_sr, buf_sc, {
@ -221,7 +225,7 @@ local function highlight_vim_syntax(
pcall(vim.api.nvim_buf_call, scratch, function()
vim.cmd('setlocal syntax=' .. ft)
vim.cmd('redraw')
vim.cmd.redraw()
---@param line integer
---@param col integer
@ -292,9 +296,10 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
local covered_lines = {}
local extmark_count = 0
---@type string[]
local new_code = {}
if use_ts then
---@type string[]
local new_code = {}
---@type table<integer, integer>
local new_map = {}
---@type string[]
@ -328,12 +333,6 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
+ highlight_treesitter(bufnr, ns, old_code, hunk.lang, old_map, pw, covered_lines, p)
if hunk.header_context and hunk.header_context_col then
local header_line = hunk.start_line - 1
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, header_line, hunk.header_context_col, {
end_col = hunk.header_context_col + #hunk.header_context,
hl_group = 'DiffsClear',
priority = p.clear,
})
local header_extmarks = highlight_text(
bufnr,
ns,
@ -370,7 +369,13 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
header_map[i] = hunk.header_start_line - 1 + i
end
extmark_count = extmark_count
+ highlight_treesitter(bufnr, ns, hunk.header_lines, 'diff', header_map, 0, nil, p)
+ highlight_treesitter(bufnr, ns, hunk.header_lines, 'diff', header_map, 0, nil, p, pw > 1)
end
local at_raw_line
if pw > 1 and opts.highlights.treesitter.enabled then
local at_buf_line = hunk.start_line - 1
at_raw_line = vim.api.nvim_buf_get_lines(bufnr, at_buf_line, at_buf_line + 1, false)[1]
end
---@type diffs.IntraChanges?
@ -407,6 +412,69 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
end
end
if
pw > 1
and hunk.header_start_line
and hunk.header_lines
and #hunk.header_lines > 0
and opts.highlights.treesitter.enabled
then
for i = 0, #hunk.header_lines - 1 do
local buf_line = hunk.header_start_line - 1 + i
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
end_col = #hunk.header_lines[i + 1],
hl_group = 'DiffsClear',
priority = p.clear,
})
local hline = hunk.header_lines[i + 1]
if hline:match('^index ') then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
end_col = 5,
hl_group = '@keyword.diff',
priority = p.syntax,
})
local dot_pos = hline:find('%.%.', 1, false)
if dot_pos then
local rest = hline:sub(dot_pos + 2)
local hash = rest:match('^(%x+)')
if hash then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, dot_pos + 1, {
end_col = dot_pos + 1 + #hash,
hl_group = '@constant.diff',
priority = p.syntax,
})
end
end
end
end
end
if pw > 1 and at_raw_line then
local at_buf_line = hunk.start_line - 1
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, at_buf_line, 0, {
end_col = #at_raw_line,
hl_group = 'DiffsClear',
priority = p.clear,
})
if opts.highlights.treesitter.enabled then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, at_buf_line, 0, {
end_col = #at_raw_line,
hl_group = '@attribute.diff',
priority = p.syntax,
})
end
end
if use_ts and hunk.header_context and hunk.header_context_col then
local header_line = hunk.start_line - 1
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, header_line, hunk.header_context_col, {
end_col = hunk.header_context_col + #hunk.header_context,
hl_group = 'DiffsClear',
priority = p.clear,
})
end
for i, line in ipairs(hunk.lines) do
local buf_line = hunk.start_line + i - 1
local line_len = #line
@ -434,6 +502,24 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
})
end
if pw > 1 then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
end_col = pw,
hl_group = 'DiffsClear',
priority = p.clear,
})
for ci = 0, pw - 1 do
local ch = line:sub(ci + 1, ci + 1)
if ch == '+' or ch == '-' then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, ci, {
end_col = ci + 1,
hl_group = ch == '+' and '@diff.plus' or '@diff.minus',
priority = p.syntax,
})
end
end
end
if line_len > pw and covered_lines[buf_line] then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, pw, {
end_col = line_len,
@ -444,17 +530,10 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
if opts.highlights.background and is_diff_line then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
end_row = buf_line + 1,
hl_group = line_hl,
hl_eol = true,
line_hl_group = line_hl,
number_hl_group = opts.highlights.gutter and number_hl or nil,
priority = p.line_bg,
})
if opts.highlights.gutter then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
number_hl_group = number_hl,
priority = p.line_bg,
})
end
end
if is_marker and line_len > pw then
@ -493,40 +572,4 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
dbg('hunk %s:%d applied %d extmarks', hunk.filename, hunk.start_line, extmark_count)
end
---@param bufnr integer
---@param ns integer
---@param hunk diffs.Hunk
---@param opts diffs.HunkOpts
function M.highlight_hunk_vim_syntax(bufnr, ns, hunk, opts)
local p = opts.highlights.priorities
local pw = hunk.prefix_width or 1
if not hunk.ft or #hunk.lines == 0 then
return
end
if #hunk.lines > opts.highlights.vim.max_lines then
return
end
local code_lines = {}
for _, line in ipairs(hunk.lines) do
table.insert(code_lines, line:sub(pw + 1))
end
local covered_lines = {}
highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, 0, p)
for buf_line in pairs(covered_lines) do
local line = hunk.lines[buf_line - hunk.start_line + 1]
if line and #line > pw then
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, pw, {
end_col = #line,
hl_group = 'DiffsClear',
priority = p.clear,
})
end
end
end
return M

View file

@ -169,6 +169,9 @@ local fast_hl_opts = {} ---@type diffs.HunkOpts
---@type table<integer, boolean>
local attached_buffers = {}
---@type table<integer, boolean>
local ft_retry_pending = {}
---@type table<integer, boolean>
local diff_windows = {}
@ -334,12 +337,15 @@ local function ensure_cache(bufnr)
has_nil_ft = true
end
end
if has_nil_ft and vim.fn.did_filetype() ~= 0 then
if has_nil_ft and vim.fn.did_filetype() ~= 0 and not ft_retry_pending[bufnr] then
ft_retry_pending[bufnr] = true
vim.schedule(function()
if vim.api.nvim_buf_is_valid(bufnr) and hunk_cache[bufnr] then
dbg('retrying filetype detection for buffer %d (was blocked by did_filetype)', bufnr)
invalidate_cache(bufnr)
vim.cmd('redraw!')
end
ft_retry_pending[bufnr] = nil
end)
end
end
@ -411,7 +417,7 @@ local function compute_highlight_groups()
local blended_add_text = blend_color(add_fg, bg, alpha)
local blended_del_text = blend_color(del_fg, bg, alpha)
vim.api.nvim_set_hl(0, 'DiffsClear', { default = true, fg = normal.fg or 0xc0c0c0 })
vim.api.nvim_set_hl(0, 'DiffsClear', { default = true, fg = normal.fg or 0xc0c0c0, bg = bg })
vim.api.nvim_set_hl(0, 'DiffsAdd', { default = true, bg = blended_add })
vim.api.nvim_set_hl(0, 'DiffsDelete', { default = true, bg = blended_del })
vim.api.nvim_set_hl(0, 'DiffsAddNr', { default = true, fg = blended_add_text, bg = blended_add })
@ -759,7 +765,7 @@ local function init()
if not entry.highlighted[i] then
local hunk = entry.hunks[i]
local clear_start = hunk.start_line - 1
local clear_end = clear_start + #hunk.lines
local clear_end = hunk.start_line + #hunk.lines
if hunk.header_start_line then
clear_start = hunk.header_start_line - 1
end
@ -776,12 +782,18 @@ local function init()
end
if #deferred_syntax > 0 then
local tick = entry.tick
dbg('deferred syntax scheduled: %d hunks tick=%d', #deferred_syntax, tick)
vim.schedule(function()
if not vim.api.nvim_buf_is_valid(bufnr) then
return
end
local cur = hunk_cache[bufnr]
if not cur or cur.tick ~= tick then
dbg(
'deferred syntax stale: cur.tick=%s captured=%d',
cur and tostring(cur.tick) or 'nil',
tick
)
return
end
local t1 = config.debug and vim.uv.hrtime() or nil
@ -791,15 +803,12 @@ local function init()
}
for _, hunk in ipairs(deferred_syntax) do
local start_row = hunk.start_line - 1
local end_row = start_row + #hunk.lines
local end_row = hunk.start_line + #hunk.lines
if hunk.header_start_line then
start_row = hunk.header_start_line - 1
end
vim.api.nvim_buf_clear_namespace(bufnr, ns, start_row, end_row)
highlight.highlight_hunk(bufnr, ns, hunk, full_opts)
if not hunk.lang and hunk.ft then
highlight.highlight_hunk_vim_syntax(bufnr, ns, hunk, full_opts)
end
end
if t1 then
dbg('deferred pass: %d hunks in %.2fms', #deferred_syntax, (vim.uv.hrtime() - t1) / 1e6)
@ -866,6 +875,7 @@ function M.attach(bufnr)
callback = function()
attached_buffers[bufnr] = nil
hunk_cache[bufnr] = nil
ft_retry_pending[bufnr] = nil
if neogit_augroup then
pcall(vim.api.nvim_del_augroup_by_id, neogit_augroup)
end
@ -947,6 +957,7 @@ M._test = {
invalidate_cache = invalidate_cache,
hunks_eq = hunks_eq,
process_pending_clear = process_pending_clear,
ft_retry_pending = ft_retry_pending,
}
return M

View file

@ -60,6 +60,15 @@ local function get_ft_from_filename(filename, repo_root)
end
local ft = vim.filetype.match({ filename = filename })
if not ft and vim.fn.did_filetype() ~= 0 then
dbg('retrying filetype match for %s (clearing did_filetype)', filename)
local saved = rawget(vim.fn, 'did_filetype')
rawset(vim.fn, 'did_filetype', function()
return 0
end)
ft = vim.filetype.match({ filename = filename })
rawset(vim.fn, 'did_filetype', saved)
end
if ft then
dbg('filetype from filename: %s', ft)
return ft
@ -125,6 +134,7 @@ end
function M.parse_buffer(bufnr)
local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
local repo_root = get_repo_root(bufnr)
---@type diffs.Hunk[]
local hunks = {}
@ -162,7 +172,6 @@ function M.parse_buffer(bufnr)
local old_remaining = nil
---@type integer?
local new_remaining = nil
local is_unified_diff = false
local function flush_hunk()
if hunk_start and #hunk_lines > 0 then
@ -201,6 +210,8 @@ function M.parse_buffer(bufnr)
for i, line in ipairs(lines) do
local diff_git_file = line:match('^diff %-%-git a/.+ b/(.+)$')
or line:match('^diff %-%-combined (.+)$')
or line:match('^diff %-%-cc (.+)$')
local neogit_file = line:match('^modified%s+(.+)$')
or (not line:match('^new file mode') and line:match('^new file%s+(.+)$'))
or (not line:match('^deleted file mode') and line:match('^deleted%s+(.+)$'))
@ -209,7 +220,6 @@ function M.parse_buffer(bufnr)
local bare_file = not hunk_start and line:match('^([^%s]+%.[^%s]+)$')
local filename = line:match('^[MADRCU%?!]%s+(.+)$') or diff_git_file or neogit_file or bare_file
if filename then
is_unified_diff = diff_git_file ~= nil
flush_hunk()
current_filename = filename
local cache_key = (repo_root or '') .. '\0' .. filename
@ -249,10 +259,17 @@ function M.parse_buffer(bufnr)
new_remaining = file_new_count
end
else
local hs, hc = line:match('%-(%d+),?(%d*)')
if hs then
file_old_start = tonumber(hs)
file_old_count = tonumber(hc) or 1
old_remaining = file_old_count
end
local hs2, hc2 = line:match('%+(%d+),?(%d*) @@')
if hs2 then
file_new_start = tonumber(hs2)
file_new_count = tonumber(hc2) or 1
new_remaining = file_new_count
end
end
local at_end, context = line:match('^(@@+.-@@+%s*)(.*)')
@ -275,13 +292,12 @@ function M.parse_buffer(bufnr)
end
elseif
line == ''
and is_unified_diff
and old_remaining
and old_remaining > 0
and new_remaining
and new_remaining > 0
then
table.insert(hunk_lines, ' ')
table.insert(hunk_lines, string.rep(' ', hunk_prefix_width))
old_remaining = old_remaining - 1
new_remaining = new_remaining - 1
elseif