abstract new xpcall wrapper into new API function safe_function

worldeditadditions_core/core/run_command.lua

@@ -5,6 +5,7 @@
 local wea_c = worldeditadditions_core
 local safe_region = dofile(wea_c.modpath.."/core/safe_region.lua")
 local human_size = wea_c.format.human_size
+local safe_function = wea_c.safe_function
 
 -- TODO: Reimplement worldedit.player_notify(player_name, msg_text)
 
@@ -34,56 +35,7 @@ local function run_command_stage2(player_name, func, parse_result, tbl_event)
 	wea_c:emit("post-execute", tbl_event)
 end
 
-local function send_error(player_name, cmdname, msg, stack_trace)
-	print("DEBUG:HAI SEND_ERROR")
-	local msg_compiled = table.concat({
-		"[//", cmdname, "] Error: ",
-		msg,
-		"\n",
-		"Please report this by opening an issue on GitHub! Bug report link (ctrl + click):\n",
 
-		"https://github.com/sbrl/Minetest-WorldEditAdditions/issues/new?title=",
-		wea_c.format.escape(stack_trace:match("^[^\n]+")), -- extract 1st line & escape
-		"&body=",
-		wea_c.format.escape(table.concat({
-			[[## Describe the bug
-What's the bug? Be clear and detailed but concise in our explanation. Don't forget to include any context, error messages, logs, and screenshots required to understand the issue if applicable.
-
-## Reproduction steps
-Steps to reproduce the behaviour:
-1. Go to '...'
-2. Click on '....'
-3. Enter this command to '....'
-4. See error
-
-## System information (please complete the following information)
-- **Operating system and version:** [e.g. iOS]
-- **Minetest version:** [e.g. 5.8.0]
-- **WorldEdit version:**
-- **WorldEditAdditions version:**
-
-Please add any other additional specific system information here too if you think it would help.
-
-## Stack trace
-- **Command name:** ]],
-			cmdname,
-			"\n",
-			"```\n",
-			stack_trace,
-			"```\n",
-		}, "")),
-		
-		"\n",
-		"-------------------------------------\n",
-		"*** Stack trace ***\n",
-		stack_trace,
-		"\n",
-		"-------------------------------------\n"
-	}, "")
-	
-	print("DEBUG:player_notify player_name", player_name, "msg_compiled", msg_compiled)
-	worldedit.player_notify(player_name, msg_compiled)
-end
 
 --- Command execution pipeline: before `paramtext` parsing but after validation.
 -- 
@@ -163,27 +115,12 @@ local function run_command(cmdname, options, player_name, paramtext)
 	
 	wea_c:emit("pre-parse", tbl_event)
 	
-	local parse_result
 	-- local did_error = false
-	local success_xpcall, error_message = xpcall(function()
+	local success_safefn, success, parse_result = safe_function(options.parse, { paramtext }, player_name, "The command crashed when parsing the arguments.", cmdname)
-		parse_result = { options.parse(paramtext) }
+	if not success_safefn then return false end -- error already sent to the player above
-	end, debug.traceback
 	
-	--[[function(error_raw)
+	print("DEBUG:run_command success_safefn", success_safefn, "success", success, "parse_result", parse_result)
-		did_error = true
-		error_message = error_raw
-		print("DEBUG:parse_result>>error", error_raw, "stack trace", debug.traceback())
-	end]]-- 
-	)
 	
-	if not success_xpcall then
-		print("DEBUG:parse_result EXIT_DUE_TO_ERROR")
-		send_error(player_name, cmdname, "The command crashed when parsing the arguments.", error_message)
-		print("DEBUG:parse_result EXIT_DUE_TO_ERROR __final_call__")
-		return false
-	end
-	
-	local success = table.remove(parse_result, 1)
 	if not success then
 		worldedit.player_notify(player_name, ("[//"..tostring(cmdname).."] "..tostring(parse_result[1])) or "Invalid usage (no further error message was provided by the command. This is probably a bug.)")
 		return false

worldeditadditions_core/core/safe_function.lua

@@ -0,0 +1,88 @@
+local weac = worldeditadditions_core
+---
+-- @module worldeditadditions_core
+
+-- ███████  █████  ███████ ███████         ███████ ███    ██ 
+-- ██      ██   ██ ██      ██              ██      ████   ██ 
+-- ███████ ███████ █████   █████           █████   ██ ██  ██ 
+--      ██ ██   ██ ██      ██              ██      ██  ██ ██ 
+-- ███████ ██   ██ ██      ███████ ███████ ██      ██   ████ 
+
+
+local function send_error(player_name, cmdname, msg, stack_trace)
+	print("DEBUG:HAI SEND_ERROR")
+	local msg_compiled = table.concat({
+		"[//", cmdname, "] Error: ",
+		msg,
+		"\n",
+		"Please report this by opening an issue on GitHub! Bug report link (ctrl + click):\n",
+		"https://github.com/sbrl/Minetest-WorldEditAdditions/issues/new?title=",
+		weac.format.escape(stack_trace:match("^[^\n]+")), -- extract 1st line & escape
+		"&body=",
+		weac.format.escape(table.concat({
+			[[## Describe the bug
+What's the bug? Be clear and detailed but concise in our explanation. Don't forget to include any context, error messages, logs, and screenshots required to understand the issue if applicable.
+
+## Reproduction steps
+Steps to reproduce the behaviour:
+1. Go to '...'
+2. Click on '....'
+3. Enter this command to '....'
+4. See error
+
+## System information (please complete the following information)
+- **Operating system and version:** [e.g. iOS]
+- **Minetest version:** [e.g. 5.8.0]
+- **WorldEdit version:**
+- **WorldEditAdditions version:**
+
+Please add any other additional specific system information here too if you think it would help.
+
+## Stack trace
+- **Command name:** ]],
+			cmdname,
+			"\n",
+			"```\n",
+			stack_trace,
+			"\n",
+			"```\n",
+		}, "")),
+
+		"\n",
+		"-------------------------------------\n",
+		"*** Stack trace ***\n",
+		stack_trace,
+		"\n",
+		"-------------------------------------\n"
+	}, "")
+
+	print("DEBUG:player_notify player_name", player_name, "msg_compiled", msg_compiled)
+	worldedit.player_notify(player_name, msg_compiled)
+end
+
+
+--- Calls the given function `fn` with the UNPACKED arguments from `args`, catching errors and sending the calling player a nice error message with a report link.
+-- 
+-- WARNING: Do NOT nest `safe_function()` calls!!!
+-- @param	fn			function		The function to call
+-- @param	args		table			The table of args to unpack and send to `fn` as arguments
+-- @param	string|nil	player_name		The name of the player affected. If nil then no message is sent to the player.
+-- @param	string		error_msg		The error message to send when `fn` inevitably crashes.
+-- @param	string|nil		cmdname		Optional. The name of the command being run.
+-- @returns	bool,any,...	A success bool (true == success), and then if success == true the rest of the arguments are the (unpacked) return values from the function called.
+function safe_function(fn, args, player_name, error_msg, cmdname)
+	local retvals
+	local success_xpcall, stack_trace = xpcall(function()
+		retvals = { fn(weac.table.unpack(args)) }
+	end, debug.traceback)
+	
+	if not success_xpcall then
+		send_error(player_name, cmdname, error_msg, stack_trace)
+		return false
+	end
+	
+	return true, weac.table.unpack(retvals)
+end
+
+
+return safe_function

worldeditadditions_core/init.lua

@@ -86,6 +86,7 @@ dofile(wea_c.modpath.."/utils/player.lua") -- Player info functions
 wea_c.setting_handler = dofile(wea_c.modpath.."/utils/setting_handler.lua") -- AFTER parser
 
 wea_c.pos = dofile(modpath.."/core/pos.lua") -- AFTER EventEmitter
+wea_c.safe_function = dofile(modpath.."/core/safe_function.lua")
 wea_c.register_command = dofile(modpath.."/core/register_command.lua")
 wea_c.command_exists = dofile(modpath.."/core/command_exists.lua")
 wea_c.fetch_command_def = dofile(modpath.."/core/fetch_command_def.lua")