Switch to mini.diff instead of gitsigns.nvim

nvim/lua/jj-diff.lua

@@ -0,0 +1,102 @@
+-- mini.diff source backed by jj.
+
+local M = {}
+
+local function resolve(buf_id)
+	local name = vim.api.nvim_buf_get_name(buf_id)
+	if name == "" then
+		return nil
+	end
+
+	local change_id, rel = name:match("^jj://([^/]+)/(.+)$")
+	if change_id then
+		-- The path in the uri is repo-relative; jj resolves it from anywhere in
+		-- the repo, so run from the current working directory.
+		return { rev = change_id .. "-", file = rel, cwd = vim.fn.getcwd() }
+	end
+
+	local path = vim.uv.fs_realpath(name)
+	if path == nil then
+		return nil
+	end
+	return { rev = "@-", file = path, cwd = vim.fs.dirname(path) }
+end
+
+local function set_ref_text(buf_id)
+	if not vim.api.nvim_buf_is_valid(buf_id) then
+		return
+	end
+	local target = resolve(buf_id)
+	if target == nil then
+		return
+	end
+	vim.system(
+		{ "jj", "file", "show", "--ignore-working-copy", "-r", target.rev, target.file },
+		{ cwd = target.cwd, text = true },
+		vim.schedule_wrap(function(obj)
+			if not vim.api.nvim_buf_is_valid(buf_id) then
+				return
+			end
+			local text = obj.code == 0 and obj.stdout or ""
+			pcall(MiniDiff.set_ref_text, buf_id, text)
+		end)
+	)
+end
+
+local function group_name(buf_id)
+	return "MiniDiffSourceJj" .. buf_id
+end
+
+local function attach(buf_id)
+	local target = resolve(buf_id)
+	if target == nil then
+		return false
+	end
+
+	if vim.fs.root(target.cwd, ".jj") == nil then
+		return false
+	end
+
+	local group = vim.api.nvim_create_augroup(group_name(buf_id), { clear = true })
+	vim.api.nvim_create_autocmd({ "BufWritePost", "BufReadPost", "BufEnter", "FocusGained", "FileChangedShellPost" }, {
+		group = group,
+		buffer = buf_id,
+		desc = "Refresh jj diff reference",
+		callback = function()
+			set_ref_text(buf_id)
+		end,
+	})
+
+	set_ref_text(buf_id)
+end
+
+local function detach(buf_id)
+	pcall(vim.api.nvim_del_augroup_by_name, group_name(buf_id))
+end
+
+M.source = {
+	name = "jj",
+	attach = attach,
+	detach = detach,
+}
+
+-- support jj:// buffers
+function M.setup()
+	local group = vim.api.nvim_create_augroup("MiniDiffJjRevisionBuffers", { clear = true })
+	vim.api.nvim_create_autocmd({ "BufWinEnter", "BufReadPost" }, {
+		group = group,
+		desc = "Enable mini.diff on jj revision buffers",
+		callback = function(ev)
+			vim.schedule(function()
+				if not vim.api.nvim_buf_is_valid(ev.buf) then
+					return
+				end
+				if vim.api.nvim_buf_get_name(ev.buf):match("^jj://") then
+					pcall(require("mini.diff").enable, ev.buf)
+				end
+			end)
+		end,
+	})
+end
+
+return M