fix format on save error on unopened buffers

Author: CapsAdmin

language_server/editor_helper.lua

@@ -305,6 +305,14 @@ do
 
 		return self.TempFiles[path]
 	end
+
+	function META:GetCurrentContent(path)
+		path = path_util.Normalize(path)
+
+		if self.TempFiles[path] ~= nil then return self.TempFiles[path] end
+
+		return fs.read(path)
+	end
 end
 
 local function normalize_path(path)

language_server/lsp.lua

@@ -414,7 +414,7 @@ lsp.methods["textDocument/codeAction"] = function(params)
 
 	if has_unused then
 		local path = to_fs_path(params.textDocument.uri)
-		local code = editor_helper:GetFileContent(path)
+		local code = editor_helper:GetCurrentContent(path)
 		local new_code = editor_helper:Format(code, path, {remove_unused = true})
 
 		if new_code ~= code then
@@ -453,7 +453,7 @@ lsp.methods["nattlua/format"] = function(params)
 end
 lsp.methods["textDocument/formatting"] = function(params)
 	local path = to_fs_path(params.textDocument.uri)
-	local code = editor_helper:GetFileContent(path)
+	local code = editor_helper:GetCurrentContent(path)
 	local new_code = editor_helper:Format(code, path)
 
 	if new_code ~= code then

test/tests/language_server/integration.lua

@@ -1,6 +1,7 @@
 local LSPClient = require("test.helpers.lsp_client")
 local lsp = require("language_server.lsp")
 local Compiler = require("nattlua.compiler")
+local fs = require("nattlua.other.fs")
 
 local function find_position(code, pattern)
 	local marker = "|"
@@ -337,6 +338,41 @@ do
 	end)
 end
 
+do
+	local old_fs_read = fs.read
+	local client = LSPClient.New()
+	client:SetWorkingDirectory("/workspace")
+	local root_uri = "file:///workspace"
+	client:Initialize(lsp, root_uri)
+	local file_uri = root_uri .. "/format_from_disk.nlua"
+	local file_path = "/workspace/format_from_disk.nlua"
+	local code = [[
+		local a=1
+		local b=2]]
+	fs.read = function(read_path)
+		if read_path == file_path then return code end
+
+		return old_fs_read(read_path)
+	end
+
+	local edits = client:Call(
+		lsp,
+		"textDocument/formatting",
+		{
+			textDocument = {uri = file_uri},
+			options = {
+				tabSize = 4,
+				insertSpaces = true,
+			},
+		}
+	)
+
+	fs.read = old_fs_read
+	assert(#edits > 0, "Formatting should return edits for files loaded from disk")
+	assert(edits[1].newText:find("local a = 1", 1, true))
+	assert(not lsp.editor_helper.OpenFiles[file_path], "Formatting should not require opening the document")
+end
+
 do
 	local client = LSPClient.New()
 	client:SetWorkingDirectory("/workspace")