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feat(gitsigns): highlight blame popup with treesitter and intra-line diffs

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Problem: gitsigns blame popups show flat `GitSignsAddPreview`/
`GitSignsDeletePreview` highlights with no treesitter syntax or
character-level intra-line diffs.

Solution: add `lua/diffs/gitsigns.lua` which patches `Popup.create`
and `Popup.update` to intercept blame popups, parse hunk sections,
clear gitsigns' own highlights, and apply `highlight_hunk` with
manual `@diff.plus`/`@diff.minus` prefix extmarks. Wired in
`plugin/diffs.lua` with `User GitAttach` lazy-load retry.
This commit is contained in:
Barrett Ruth 2026-03-06 08:35:26 -05:00
parent c64ca827f3
commit 09a0418942
3 changed files with 432 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

183
lua/diffs/gitsigns.lua Normal file
View file

@ -0,0 +1,183 @@
local M = {}
local api = vim.api
local fn = vim.fn
local dbg = require('diffs.log').dbg
local ns = api.nvim_create_namespace('diffs-gitsigns')
local gs_popup_ns = api.nvim_create_namespace('gitsigns_popup')
local patched = false
---@param ft string
---@return string?
local function get_lang(ft)
local lang = vim.treesitter.language.get_lang(ft)
if not lang then
return nil
end
local ok = pcall(vim.treesitter.language.inspect, lang)
return ok and lang or nil
end
---@param bufnr integer
---@param src_filename string
---@param src_ft string?
---@param src_lang string?
---@return diffs.Hunk[]
function M.parse_blame_hunks(bufnr, src_filename, src_ft, src_lang)
local lines = api.nvim_buf_get_lines(bufnr, 0, -1, false)
local hunks = {}
local hunk_lines = {}
local hunk_start = nil
for i, line in ipairs(lines) do
if line:match('^Hunk %d+ of %d+') then
if hunk_start and #hunk_lines > 0 then
table.insert(hunks, {
filename = src_filename,
ft = src_ft,
lang = src_lang,
start_line = hunk_start,
prefix_width = 1,
quote_width = 0,
lines = hunk_lines,
})
end
hunk_lines = {}
hunk_start = i
elseif hunk_start then
if line:match('^%(guessed:') then
hunk_start = i
else
local prefix = line:sub(1, 1)
if prefix == ' ' or prefix == '+' or prefix == '-' then
if #hunk_lines == 0 then
hunk_start = i - 1
end
table.insert(hunk_lines, line)
end
end
end
end
if hunk_start and #hunk_lines > 0 then
table.insert(hunks, {
filename = src_filename,
ft = src_ft,
lang = src_lang,
start_line = hunk_start,
prefix_width = 1,
quote_width = 0,
lines = hunk_lines,
})
end
return hunks
end
---@param preview_winid integer
---@param preview_bufnr integer
local function on_preview(preview_winid, preview_bufnr)
local ok, err = pcall(function()
if not api.nvim_buf_is_valid(preview_bufnr) then
return
end
if not api.nvim_win_is_valid(preview_winid) then
return
end
local win = api.nvim_get_current_win()
if win == preview_winid then
win = fn.win_getid(fn.winnr('#'))
end
if win == -1 or win == 0 or not api.nvim_win_is_valid(win) then
return
end
local srcbuf = api.nvim_win_get_buf(win)
if not api.nvim_buf_is_loaded(srcbuf) then
return
end
local ft = vim.bo[srcbuf].filetype
local name = api.nvim_buf_get_name(srcbuf)
if not name or name == '' then
name = ft and ('a.' .. ft) or 'unknown'
end
local lang = ft and get_lang(ft) or nil
local hunks = M.parse_blame_hunks(preview_bufnr, name, ft, lang)
if #hunks == 0 then
return
end
local diff_start = hunks[1].start_line
local last = hunks[#hunks]
local diff_end = last.start_line + #last.lines
api.nvim_buf_clear_namespace(preview_bufnr, gs_popup_ns, diff_start, diff_end)
api.nvim_buf_clear_namespace(preview_bufnr, ns, diff_start, diff_end)
local opts = require('diffs').get_highlight_opts()
local highlight = require('diffs.highlight')
for _, hunk in ipairs(hunks) do
highlight.highlight_hunk(preview_bufnr, ns, hunk, opts)
for j, line in ipairs(hunk.lines) do
local ch = line:sub(1, 1)
if ch == '+' or ch == '-' then
pcall(api.nvim_buf_set_extmark, preview_bufnr, ns, hunk.start_line + j - 1, 0, {
end_col = 1,
hl_group = ch == '+' and '@diff.plus' or '@diff.minus',
priority = opts.highlights.priorities.syntax,
})
end
end
end
dbg('gitsigns blame: highlighted %d hunks in popup buf %d', #hunks, preview_bufnr)
end)
if not ok then
dbg('gitsigns blame error: %s', err)
end
end
---@return boolean
function M.setup()
if patched then
return true
end
local pop_ok, Popup = pcall(require, 'gitsigns.popup')
if not pop_ok or not Popup then
return false
end
Popup.create = (function(orig)
return function(...)
local winid, bufnr = orig(...)
on_preview(winid, bufnr)
return winid, bufnr
end
end)(Popup.create)
Popup.update = (function(orig)
return function(winid, bufnr, ...)
orig(winid, bufnr, ...)
on_preview(winid, bufnr)
end
end)(Popup.update)
patched = true
dbg('gitsigns popup patched')
return true
end
M._test = {
parse_blame_hunks = M.parse_blame_hunks,
on_preview = on_preview,
ns = ns,
gs_popup_ns = gs_popup_ns,
}
return M

13
plugin/diffs.lua
View file

@ -5,6 +5,19 @@ vim.g.loaded_diffs = 1
require('diffs.commands').setup()
local gs_cfg = (vim.g.diffs or {}).gitsigns
if gs_cfg == true or type(gs_cfg) == 'table' then
if not require('diffs.gitsigns').setup() then
vim.api.nvim_create_autocmd('User', {
pattern = 'GitAttach',
once = true,
callback = function()
require('diffs.gitsigns').setup()
end,
})
end
end
vim.api.nvim_create_autocmd('FileType', {
pattern = require('diffs').compute_filetypes(vim.g.diffs or {}),
callback = function(args)

236
spec/gitsigns_spec.lua Normal file
View file

@ -0,0 +1,236 @@
require('spec.helpers')
local gs = require('diffs.gitsigns')
local function setup_highlight_groups()
local normal = vim.api.nvim_get_hl(0, { name = 'Normal' })
local diff_add = vim.api.nvim_get_hl(0, { name = 'DiffAdd' })
local diff_delete = vim.api.nvim_get_hl(0, { name = 'DiffDelete' })
vim.api.nvim_set_hl(0, 'DiffsClear', { fg = normal.fg or 0xc0c0c0 })
vim.api.nvim_set_hl(0, 'DiffsAdd', { bg = diff_add.bg or 0x2e4a3a })
vim.api.nvim_set_hl(0, 'DiffsDelete', { bg = diff_delete.bg or 0x4a2e3a })
vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
end
local function create_buffer(lines)
local bufnr = vim.api.nvim_create_buf(false, true)
vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines or {})
return bufnr
end
local function delete_buffer(bufnr)
if bufnr and vim.api.nvim_buf_is_valid(bufnr) then
vim.api.nvim_buf_delete(bufnr, { force = true })
end
end
describe('gitsigns', function()
describe('parse_blame_hunks', function()
it('parses a single hunk', function()
local bufnr = create_buffer({
'commit abc1234',
'Author: Test User',
'',
'Hunk 1 of 1',
' local x = 1',
'-local y = 2',
'+local y = 3',
' local z = 4',
})
local hunks = gs.parse_blame_hunks(bufnr, 'test.lua', 'lua', 'lua')
assert.are.equal(1, #hunks)
assert.are.equal('test.lua', hunks[1].filename)
assert.are.equal('lua', hunks[1].ft)
assert.are.equal('lua', hunks[1].lang)
assert.are.equal(1, hunks[1].prefix_width)
assert.are.equal(0, hunks[1].quote_width)
assert.are.equal(4, #hunks[1].lines)
assert.are.equal(4, hunks[1].start_line)
assert.are.equal(' local x = 1', hunks[1].lines[1])
assert.are.equal('-local y = 2', hunks[1].lines[2])
assert.are.equal('+local y = 3', hunks[1].lines[3])
delete_buffer(bufnr)
end)
it('parses multiple hunks', function()
local bufnr = create_buffer({
'commit abc1234',
'',
'Hunk 1 of 2',
'-local a = 1',
'+local a = 2',
'Hunk 2 of 2',
' local b = 3',
'+local c = 4',
})
local hunks = gs.parse_blame_hunks(bufnr, 'test.lua', 'lua', 'lua')
assert.are.equal(2, #hunks)
assert.are.equal(2, #hunks[1].lines)
assert.are.equal(2, #hunks[2].lines)
delete_buffer(bufnr)
end)
it('skips guessed-offset lines', function()
local bufnr = create_buffer({
'commit abc1234',
'',
'Hunk 1 of 1',
'(guessed: hunk offset may be wrong)',
' local x = 1',
'+local y = 2',
})
local hunks = gs.parse_blame_hunks(bufnr, 'test.lua', 'lua', 'lua')
assert.are.equal(1, #hunks)
assert.are.equal(2, #hunks[1].lines)
assert.are.equal(' local x = 1', hunks[1].lines[1])
delete_buffer(bufnr)
end)
it('returns empty table when no hunks present', function()
local bufnr = create_buffer({
'commit abc1234',
'Author: Test User',
'Date: 2024-01-01',
})
local hunks = gs.parse_blame_hunks(bufnr, 'test.lua', 'lua', 'lua')
assert.are.equal(0, #hunks)
delete_buffer(bufnr)
end)
it('handles hunk with no diff lines after header', function()
local bufnr = create_buffer({
'Hunk 1 of 1',
'some non-diff text',
})
local hunks = gs.parse_blame_hunks(bufnr, 'test.lua', 'lua', 'lua')
assert.are.equal(0, #hunks)
delete_buffer(bufnr)
end)
end)
describe('on_preview', function()
before_each(function()
setup_highlight_groups()
end)
it('applies extmarks to popup buffer with diff content', function()
local bufnr = create_buffer({
'commit abc1234',
'',
'Hunk 1 of 1',
' local x = 1',
'-local y = 2',
'+local y = 3',
})
local winid = vim.api.nvim_open_win(bufnr, false, {
relative = 'editor',
width = 40,
height = 10,
row = 0,
col = 0,
})
gs._test.on_preview(winid, bufnr)
local extmarks = vim.api.nvim_buf_get_extmarks(bufnr, gs._test.ns, 0, -1, { details = true })
assert.is_true(#extmarks > 0)
vim.api.nvim_win_close(winid, true)
delete_buffer(bufnr)
end)
it('clears gitsigns_popup namespace on diff region', function()
local bufnr = create_buffer({
'commit abc1234',
'',
'Hunk 1 of 1',
' local x = 1',
'+local y = 2',
})
vim.api.nvim_buf_set_extmark(bufnr, gs._test.gs_popup_ns, 3, 0, {
end_col = 12,
hl_group = 'GitSignsAddPreview',
})
vim.api.nvim_buf_set_extmark(bufnr, gs._test.gs_popup_ns, 4, 0, {
end_col = 12,
hl_group = 'GitSignsAddPreview',
})
local winid = vim.api.nvim_open_win(bufnr, false, {
relative = 'editor',
width = 40,
height = 10,
row = 0,
col = 0,
})
gs._test.on_preview(winid, bufnr)
local gs_extmarks =
vim.api.nvim_buf_get_extmarks(bufnr, gs._test.gs_popup_ns, 0, -1, { details = true })
assert.are.equal(0, #gs_extmarks)
vim.api.nvim_win_close(winid, true)
delete_buffer(bufnr)
end)
it('does not error on invalid buffer', function()
assert.has_no.errors(function()
gs._test.on_preview(0, 99999)
end)
end)
end)
describe('setup', function()
it('returns false when gitsigns.popup is not available', function()
local saved = package.loaded['gitsigns.popup']
package.loaded['gitsigns.popup'] = nil
package.preload['gitsigns.popup'] = nil
local fresh = loadfile('lua/diffs/gitsigns.lua')()
local result = fresh.setup()
assert.is_false(result)
package.loaded['gitsigns.popup'] = saved
end)
it('patches gitsigns.popup when available', function()
local create_called = false
local update_called = false
local mock_popup = {
create = function()
create_called = true
local bufnr = create_buffer({ 'test' })
local winid = vim.api.nvim_open_win(bufnr, false, {
relative = 'editor',
width = 10,
height = 1,
row = 0,
col = 0,
})
return winid, bufnr
end,
update = function()
update_called = true
end,
}
local saved = package.loaded['gitsigns.popup']
package.loaded['gitsigns.popup'] = mock_popup
local fresh = loadfile('lua/diffs/gitsigns.lua')()
local result = fresh.setup()
assert.is_true(result)
mock_popup.create()
assert.is_true(create_called)
mock_popup.update(0, 0)
assert.is_true(update_called)
package.loaded['gitsigns.popup'] = saved
end)
end)
end)