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fix(highlight): use hl_group instead of line_hl_group for diff backgrounds

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line_hl_group bg occupies a separate rendering channel from hl_group in
Neovim's extmark system, causing character-level bg-only highlights to be
invisible regardless of priority. Switching to hl_group + hl_eol ensures
all backgrounds compete in the same channel.

Also reorders priorities (Normal 198 < line bg 199 < syntax 200 < char
bg 201), bumps char-level blend alpha from 0.4 to 0.7 for visibility,
and adds debug logging throughout the intra pipeline.
This commit is contained in:
Barrett Ruth 2026-02-06 18:28:22 -05:00
parent f1c13966ba
commit cc947167c3
5 changed files with 427 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

304
spec/highlight_spec.lua
View file

@ -43,6 +43,11 @@ describe('highlight', function()
enabled = false,
max_lines = 200,
},
intra = {
enabled = false,
algorithm = 'native',
max_lines = 500,
},
},
}
if overrides then
@ -322,7 +327,7 @@ describe('highlight', function()
local extmarks = get_extmarks(bufnr)
local has_diff_add = false
for _, mark in ipairs(extmarks) do
if mark[4] and mark[4].line_hl_group == 'DiffsAdd' then
if mark[4] and mark[4].hl_group == 'DiffsAdd' then
has_diff_add = true
break
end
@ -355,7 +360,7 @@ describe('highlight', function()
local extmarks = get_extmarks(bufnr)
local has_diff_delete = false
for _, mark in ipairs(extmarks) do
if mark[4] and mark[4].line_hl_group == 'DiffsDelete' then
if mark[4] and mark[4].hl_group == 'DiffsDelete' then
has_diff_delete = true
break
end
@ -388,7 +393,7 @@ describe('highlight', function()
local extmarks = get_extmarks(bufnr)
local has_line_hl = false
for _, mark in ipairs(extmarks) do
if mark[4] and mark[4].line_hl_group then
if mark[4] and (mark[4].hl_group == 'DiffsAdd' or mark[4].hl_group == 'DiffsDelete') then
has_line_hl = true
break
end
@ -520,7 +525,7 @@ describe('highlight', function()
local extmarks = get_extmarks(bufnr)
local has_diff_add = false
for _, mark in ipairs(extmarks) do
if mark[4] and mark[4].line_hl_group == 'DiffsAdd' then
if mark[4] and mark[4].hl_group == 'DiffsAdd' then
has_diff_add = true
break
end
@ -668,7 +673,7 @@ describe('highlight', function()
local extmarks = get_extmarks(bufnr)
local has_diff_add = false
for _, mark in ipairs(extmarks) do
if mark[4] and mark[4].line_hl_group == 'DiffsAdd' then
if mark[4] and mark[4].hl_group == 'DiffsAdd' then
has_diff_add = true
break
end
@ -727,6 +732,295 @@ describe('highlight', function()
assert.is_true(has_normal)
delete_buffer(bufnr)
end)
it('uses hl_group not line_hl_group for line backgrounds', function()
local bufnr = create_buffer({
'@@ -1,2 +1,1 @@',
'-local x = 1',
'+local y = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local y = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({ highlights = { background = true } })
)
local extmarks = get_extmarks(bufnr)
for _, mark in ipairs(extmarks) do
local d = mark[4]
if d and (d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete') then
assert.is_true(d.hl_eol == true)
assert.is_nil(d.line_hl_group)
end
end
delete_buffer(bufnr)
end)
it('line bg priority > Normal priority', function()
local bufnr = create_buffer({
'@@ -1,2 +1,1 @@',
'-local x = 1',
'+local y = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local y = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({ highlights = { background = true } })
)
local extmarks = get_extmarks(bufnr)
local normal_priority = nil
local line_bg_priority = nil
for _, mark in ipairs(extmarks) do
local d = mark[4]
if d and d.hl_group == 'Normal' then
normal_priority = d.priority
end
if d and (d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete') then
line_bg_priority = d.priority
end
end
assert.is_not_nil(normal_priority)
assert.is_not_nil(line_bg_priority)
assert.is_true(line_bg_priority > normal_priority)
delete_buffer(bufnr)
end)
it('char-level extmarks have higher priority than line bg', function()
vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
local bufnr = create_buffer({
'@@ -1,2 +1,2 @@',
'-local x = 1',
'+local x = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local x = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({
highlights = {
background = true,
intra = { enabled = true, algorithm = 'native', max_lines = 500 },
},
})
)
local extmarks = get_extmarks(bufnr)
local line_bg_priority = nil
local char_bg_priority = nil
for _, mark in ipairs(extmarks) do
local d = mark[4]
if d and (d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete') then
line_bg_priority = d.priority
end
if d and (d.hl_group == 'DiffsAddText' or d.hl_group == 'DiffsDeleteText') then
char_bg_priority = d.priority
end
end
assert.is_not_nil(line_bg_priority)
assert.is_not_nil(char_bg_priority)
assert.is_true(char_bg_priority > line_bg_priority)
delete_buffer(bufnr)
end)
it('creates char-level extmarks for changed characters', function()
vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
local bufnr = create_buffer({
'@@ -1,2 +1,2 @@',
'-local x = 1',
'+local x = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local x = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({
highlights = { intra = { enabled = true, algorithm = 'native', max_lines = 500 } },
})
)
local extmarks = get_extmarks(bufnr)
local add_text_marks = {}
local del_text_marks = {}
for _, mark in ipairs(extmarks) do
local d = mark[4]
if d and d.hl_group == 'DiffsAddText' then
table.insert(add_text_marks, mark)
end
if d and d.hl_group == 'DiffsDeleteText' then
table.insert(del_text_marks, mark)
end
end
assert.is_true(#add_text_marks > 0)
assert.is_true(#del_text_marks > 0)
delete_buffer(bufnr)
end)
it('does not create char-level extmarks when intra disabled', function()
local bufnr = create_buffer({
'@@ -1,2 +1,2 @@',
'-local x = 1',
'+local x = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local x = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({
highlights = { intra = { enabled = false, algorithm = 'native', max_lines = 500 } },
})
)
local extmarks = get_extmarks(bufnr)
for _, mark in ipairs(extmarks) do
local d = mark[4]
assert.is_not_equal('DiffsAddText', d and d.hl_group)
assert.is_not_equal('DiffsDeleteText', d and d.hl_group)
end
delete_buffer(bufnr)
end)
it('does not create char-level extmarks for pure additions', function()
vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
local bufnr = create_buffer({
'@@ -1,0 +1,2 @@',
'+local x = 1',
'+local y = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '+local x = 1', '+local y = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({
highlights = { intra = { enabled = true, algorithm = 'native', max_lines = 500 } },
})
)
local extmarks = get_extmarks(bufnr)
for _, mark in ipairs(extmarks) do
local d = mark[4]
assert.is_not_equal('DiffsAddText', d and d.hl_group)
assert.is_not_equal('DiffsDeleteText', d and d.hl_group)
end
delete_buffer(bufnr)
end)
it('enforces priority order: Normal < line bg < syntax < char bg', function()
vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
local bufnr = create_buffer({
'@@ -1,2 +1,2 @@',
'-local x = 1',
'+local x = 2',
})
local hunk = {
filename = 'test.lua',
lang = 'lua',
start_line = 1,
lines = { '-local x = 1', '+local x = 2' },
}
highlight.highlight_hunk(
bufnr,
ns,
hunk,
default_opts({
highlights = {
background = true,
intra = { enabled = true, algorithm = 'native', max_lines = 500 },
},
})
)
local extmarks = get_extmarks(bufnr)
local priorities = { normal = {}, line_bg = {}, syntax = {}, char_bg = {} }
for _, mark in ipairs(extmarks) do
local d = mark[4]
if d then
if d.hl_group == 'Normal' then
table.insert(priorities.normal, d.priority)
elseif d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete' then
table.insert(priorities.line_bg, d.priority)
elseif d.hl_group == 'DiffsAddText' or d.hl_group == 'DiffsDeleteText' then
table.insert(priorities.char_bg, d.priority)
elseif d.hl_group and d.hl_group:match('^@.*%.lua$') then
table.insert(priorities.syntax, d.priority)
end
end
end
assert.is_true(#priorities.normal > 0)
assert.is_true(#priorities.line_bg > 0)
assert.is_true(#priorities.syntax > 0)
assert.is_true(#priorities.char_bg > 0)
local max_normal = math.max(unpack(priorities.normal))
local min_line_bg = math.min(unpack(priorities.line_bg))
local min_syntax = math.min(unpack(priorities.syntax))
local min_char_bg = math.min(unpack(priorities.char_bg))
assert.is_true(max_normal < min_line_bg)
assert.is_true(min_line_bg < min_syntax)
assert.is_true(min_syntax < min_char_bg)
delete_buffer(bufnr)
end)
end)
describe('diff header highlighting', function()