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feat(jj): route working-copy conflicts to the merge-tool layout #278

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Merged
dlyongemallo merged 1 commit into from
Jul 1, 2026
Merged

feat(jj): route working-copy conflicts to the merge-tool layout #278

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281 changes: 281 additions & 0 deletions lua/diffview/tests/functional/jj_adapter_spec.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -740,6 +740,287 @@ describe("diffview.vcs.adapters.jj", function()
end)
)
end)

describe("merge conflict detection", function()
-- Build a 2-parent merge with a conflicting file. Returns the change
-- ids of the base, ours, and theirs commits.
local function make_conflict(filename)
filename = filename or "file.txt"
repo.write(filename, "line1\n")
repo.jj({ "describe", "-m", "initial" })
local base = repo.jj({ "log", "-r", "@", "--no-graph", "-T", "change_id.short()" })

repo.jj({ "new", "-m", "left" })
repo.write(filename, "left\n")
local ours = repo.jj({ "log", "-r", "@", "--no-graph", "-T", "change_id.short()" })

repo.jj({ "new", base, "-m", "right" })
repo.write(filename, "right\n")
local theirs = repo.jj({ "log", "-r", "@", "--no-graph", "-T", "change_id.short()" })

repo.jj({ "new", ours, theirs, "-m", "merge" })

return base, ours, theirs
end

it(
"detects a 2-sided conflict and returns commit ids for OURS/THEIRS/BASE",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict()
local adapter = repo.adapter()

local err, ctx = await(adapter:_query_merge_context())
assert.is_nil(err)
assert.is_not_nil(ctx)
assert.same({ "file.txt" }, ctx.paths)
-- Commit ids are full 40-char hex.
assert.equals(40, #ctx.ours)
assert.equals(40, #ctx.theirs)
assert.equals(40, ctx.base and #ctx.base or 0)
assert.not_equals(ctx.ours, ctx.theirs)
end)
)

it(
"returns nil when the working copy has no conflicts",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

repo.write("file.txt", "clean\n")
repo.jj({ "describe", "-m", "clean" })

local adapter = repo.adapter()
local err, ctx = await(adapter:_query_merge_context())
assert.is_nil(err)
assert.is_nil(ctx)
end)
)

it(
"routes conflicting paths into the conflicts bucket with the merge layout",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict()

local adapter = repo.adapter()
local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.LOCAL)
local args = adapter:rev_to_args(left, right)

local Diff3Hor = require("diffview.scene.layouts.diff_3_hor").Diff3Hor
local err, files, conflicts = await(
adapter:tracked_files(
left,
right,
args,
"working",
{ default_layout = Diff2, merge_layout = Diff3Hor }
)
)

assert.is_nil(err)
for _, f in ipairs(files) do
assert.not_equals("file.txt", f.path)
end
assert.equals(1, #conflicts)
assert.equals("file.txt", conflicts[1].path)
assert.equals("U", conflicts[1].status)
assert.equals("conflicting", conflicts[1].kind)
end)
)

it(
"populates `get_merge_context` after `tracked_files` from the cache",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict()

local adapter = repo.adapter()
-- Nothing runs before tracked_files, so the cache is unset.
assert.is_nil(adapter:get_merge_context())

local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.LOCAL)
local args = adapter:rev_to_args(left, right)
local Diff3Hor = require("diffview.scene.layouts.diff_3_hor").Diff3Hor

await(
adapter:tracked_files(
left,
right,
args,
"working",
{ default_layout = Diff2, merge_layout = Diff3Hor }
)
)

local ctx = adapter:get_merge_context()
assert.is_not_nil(ctx)
assert.equals(40, #ctx.ours.hash)
assert.equals(40, #ctx.theirs.hash)
assert.equals(40, #ctx.base.hash)
end)
)

it(
"get_merge_context returns nil when there is no conflict",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

repo.write("file.txt", "clean\n")
repo.jj({ "describe", "-m", "clean" })

local adapter = repo.adapter()
local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.LOCAL)
local args = adapter:rev_to_args(left, right)

await(
adapter:tracked_files(
left,
right,
args,
"working",
{ default_layout = Diff2, merge_layout = Diff2 }
)
)

assert.is_nil(adapter:get_merge_context())
end)
)

it(
"does not inject working-copy conflicts into a commit-range diff (right != LOCAL)",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict()

local adapter = repo.adapter()
-- Both endpoints are commits, not LOCAL: this simulates
-- `:DiffviewOpen v1.0..v1.1` where the working copy `@` isn't the
-- right endpoint.
local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local Diff3Hor = require("diffview.scene.layouts.diff_3_hor").Diff3Hor

local err, _, conflicts = await(
adapter:tracked_files(
left,
right,
{},
"working",
{ default_layout = Diff2, merge_layout = Diff3Hor }
)
)

assert.is_nil(err)
assert.equals(0, #conflicts)
assert.is_nil(adapter:get_merge_context())
end)
)

it(
"excludes conflicts outside the requested `path_args` scope",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict("bar/file.txt")

local adapter = repo.adapter()
adapter.ctx.path_args = { "foo" }
local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.LOCAL)
local args = adapter:rev_to_args(left, right)
local Diff3Hor = require("diffview.scene.layouts.diff_3_hor").Diff3Hor

local err, _, conflicts = await(
adapter:tracked_files(
left,
right,
args,
"working",
{ default_layout = Diff2, merge_layout = Diff3Hor }
)
)

assert.is_nil(err)
assert.equals(0, #conflicts)
end)
)

it(
"sets `revs.d` to a null-tree Rev rather than nil, so 4-way layouts have a valid BASE pane",
helpers.async_test(function()
if not jj_available() then
pending("jj not installed")
return
end

make_conflict()

local adapter = repo.adapter()
-- Force the null-tree branch: pretend fork_point returned nothing.
local orig_query = adapter._query_merge_context
adapter._query_merge_context = function(self, callback)
return orig_query(self, function(err, ctx)
if ctx then
ctx.base = nil
end
callback(err, ctx)
end)
end

local left = adapter.Rev(RevType.COMMIT, adapter.Rev.NULL_TREE_SHA)
local right = adapter.Rev(RevType.LOCAL)
local args = adapter:rev_to_args(left, right)
local Diff4Mixed = require("diffview.scene.layouts.diff_4_mixed").Diff4Mixed

local err, _, conflicts = await(
adapter:tracked_files(
left,
right,
args,
"working",
{ default_layout = Diff2, merge_layout = Diff4Mixed }
)
)

assert.is_nil(err)
assert.equals(1, #conflicts)
local entry = conflicts[1]
local d_rev = entry.layout.d.file.rev
assert.is_not_nil(d_rev, "revs.d must not be nil (would crash Diff4 on layout open)")
assert.equals(adapter.Rev.NULL_TREE_SHA, d_rev:object_name())
end)
)
end)

describe("file_history_worker", function()
it(
"streams one entry per commit",
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