refactor(nvim): make session sidecar generic (not only for tabpages)

1 files changed, 29 insertions, 15 deletions

diff --git a/.config/nvim/plugin/50-session.lua b/.config/nvim/plugin/50-session.lua
index 5dc033f..9d1a8bf 100644
--- a/.config/nvim/plugin/50-session.lua
+++ b/.config/nvim/plugin/50-session.lua
@@ -9,11 +9,31 @@ if not vim.uv.fs_stat(session_dir) then
 	vim.notify("Sessions save directory created at " .. session_dir)
 end
 
--- :mksession doesn't persist tab-local vars (t:tabname), so we write tab names to a sidecar
--- JSON file alongside the .vim session. Names are stored positionally because :mksession
--- recreates tabs in their original order, making the index stable across reloads.
-local function tabnames_path(path)
-	return (path:gsub("%.vim$", "")) .. ".tabnames.json"
+-- :mksession doesn't persist everything we want (e.g. tab-local t:tabname), so we keep a
+-- sidecar JSON object alongside the .vim session for extra data. Tab names live under the
+-- `tabnames` key, stored positionally because :mksession recreates tabs in their original
+-- order, making the index stable across reloads.
+local function sidecar_path(path)
+	return (path:gsub("%.vim$", "")) .. ".json"
+end
+
+local function read_sidecar(path)
+	local f = io.open(sidecar_path(path), "r")
+	if not f then
+		return {}
+	end
+	local content = f:read("*a")
+	f:close()
+	local ok, data = pcall(vim.json.decode, content)
+	return (ok and type(data) == "table") and data or {}
+end
+
+local function write_sidecar(path, data)
+	local f = io.open(sidecar_path(path), "w")
+	if f then
+		f:write(vim.json.encode(data))
+		f:close()
+	end
 end
 
 local function save_session(path)
@@ -24,21 +44,15 @@ local function save_session(path)
 		local ok, name = pcall(vim.api.nvim_tabpage_get_var, tp, "tabname")
 		names[i] = (ok and type(name) == "string") and name or ""
 	end
-	local f = io.open(tabnames_path(path), "w")
-	if f then
-		f:write(vim.json.encode(names))
-		f:close()
-	end
+	write_sidecar(path, { tabnames = names })
 end
 
 local function load_session(path)
 	vim.cmd.source(path)
-	local f = io.open(tabnames_path(path), "r")
-	if not f then
+	local names = read_sidecar(path).tabnames
+	if not names then
 		return
 	end
-	local names = vim.json.decode(f:read("*a"))
-	f:close()
 	for i, tp in ipairs(vim.api.nvim_list_tabpages()) do
 		if names[i] and names[i] ~= "" then
 			vim.api.nvim_tabpage_set_var(tp, "tabname", names[i])
@@ -54,7 +68,7 @@ end
 
 local function delete_session(path)
 	vim.fs.rm(path)
-	local sidecar = tabnames_path(path)
+	local sidecar = sidecar_path(path)
 	if vim.uv.fs_stat(sidecar) then
 		vim.fs.rm(sidecar)
 	end