use xpcall to process systems

.vscode/settings.json

@@ -8,7 +8,6 @@
     "markdown.extension.toc.levels": "2..6",
     "markdown.extension.toc.omittedFromToc": {
         "README.md": [
-            "# Changelog",
             "# API Reference"
         ]
     }

README.md

@@ -57,6 +57,11 @@
   - [Classes](#classes)
     - [Chunk](#chunk)
     - [Builder](#builder)
+- [Changelog](#changelog)
+  - [vX.X.X](#vxxx)
+  - [v1.2.0](#v120)
+  - [v1.1.0](#v110)
+  - [v1.0.0](#v100)
 - [License](#license)
 
 ## Introduction
@@ -1246,32 +1251,33 @@ builder_mt:epilogue :: {} -> builder
 builder_mt:destruction_policy :: id -> builder
 ```
 
-## License
+## Changelog
 
-`evolved.lua` is licensed under the [MIT License][license]. For more details, see the [LICENSE.md](./LICENSE.md) file in the repository.
+### vX.X.X
-
-# Changelog
-
-## vX.X.X
 
 - The internal garbage collector now collects more garbage
 - Added the new [`evolved.cancel`](#evolvedcancel) function
+- Improved system processing debugging experience with stack traces on errors
 
-## v1.2.0
+### v1.2.0
 
 - Added the new [`evolved.name`](#evolvedname-1) function
 - Added the new [`evolved.multi_spawn`](#evolvedmulti_spawn) and [`evolved.multi_clone`](#evolvedmulti_clone) functions
 - Added the new [`evolved.INTERNAL`](#evolvedinternal) fragment trait
 
-## v1.1.0
+### v1.1.0
 
 - [`Systems`](#systems) can be queries themselves now
 - Added the new [`evolved.REQUIRES`](#evolvedrequires) fragment trait
 
-## v1.0.0
+### v1.0.0
 
 - Initial release
 
+## License
+
+`evolved.lua` is licensed under the [MIT License][license]. For more details, see the [LICENSE.md](./LICENSE.md) file in the repository.
+
 # API Reference
 
 ## Predefs

evolved.lua

@@ -191,7 +191,6 @@ __builder_mt.__index = __builder_mt
 
 local __lua_error = error
 local __lua_next = next
-local __lua_pcall = pcall
 local __lua_print = print
 local __lua_select = select
 local __lua_setmetatable = setmetatable
@@ -199,6 +198,7 @@ local __lua_string_format = string.format
 local __lua_table_concat = table.concat
 local __lua_table_sort = table.sort
 local __lua_tostring = tostring
+local __lua_xpcall = xpcall
 
 ---@type fun(narray: integer, nhash: integer): table
 local __lua_table_new = (function()
@@ -207,7 +207,7 @@ local __lua_table_new = (function()
     -- https://forum.defold.com/t/solved-is-luajit-table-new-function-available-in-defold/78623
 
     do
-        ---@diagnostic disable-next-line: undefined-field
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_new = table and table.new
         if table_new then
             ---@cast table_new fun(narray: integer, nhash: integer): table
@@ -216,7 +216,7 @@ local __lua_table_new = (function()
     end
 
     do
-        ---@diagnostic disable-next-line: undefined-field
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_create = table and table.create
         if table_create then
             ---@cast table_create fun(count: integer, value: any): table
@@ -248,7 +248,7 @@ local __lua_table_clear = (function()
     -- https://forum.defold.com/t/solved-is-luajit-table-new-function-available-in-defold/78623
 
     do
-        ---@diagnostic disable-next-line: undefined-field
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_clear = table and table.clear
         if table_clear then
             ---@cast table_clear fun(tab: table)
@@ -279,7 +279,7 @@ local __lua_table_move = (function()
     -- https://create.roblox.com/docs/reference/engine/libraries/table#move
 
     do
-        ---@diagnostic disable-next-line: deprecated
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_move = table and table.move
         if table_move then
             ---@cast table_move fun(a1: table, f: integer, e: integer, t: integer, a2?: table): table
@@ -316,18 +316,34 @@ end)()
 ---@type fun(lst: table, i: integer, j: integer): ...
 local __lua_table_unpack = (function()
     do
-        ---@diagnostic disable-next-line: deprecated
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_unpack = unpack
         if table_unpack then return table_unpack end
     end
 
     do
-        ---@diagnostic disable-next-line: deprecated
+        ---@diagnostic disable-next-line: deprecated, undefined-field
         local table_unpack = table and table.unpack
         if table_unpack then return table_unpack end
     end
 end)()
 
+---@type fun(message?: any, level?: integer): string
+local __lua_debug_traceback = (function()
+    do
+        ---@diagnostic disable-next-line: deprecated, undefined-field
+        local debug_traceback = debug and debug.traceback
+        if debug_traceback then
+            return debug_traceback
+        end
+    end
+
+    ---@type fun(message?: any, level?: integer): string
+    return function(message)
+        return __lua_tostring(message)
+    end
+end)()
+
 ---
 ---
 ---
@@ -344,8 +360,8 @@ end
 ---@param fmt string
 ---@param ... any
 local function __warning_fmt(fmt, ...)
-    __lua_print(__lua_string_format('| evolved.lua (w) | %s',
+    __lua_print(__lua_debug_traceback(__lua_string_format('| evolved.lua (w) | %s',
-        __lua_string_format(fmt, ...)))
+        __lua_string_format(fmt, ...))))
 end
 
 ---
@@ -4446,6 +4462,24 @@ function __iterator_fns.__execute_iterator(execute_state)
     __release_table(__table_pool_tag.execute_state, execute_state, true)
 end
 
+---@type { [1]: evolved.query, [2]: evolved.execute }
+local __query_execute_external_arguments = {}
+
+---@param query? evolved.query
+---@param execute? evolved.execute
+local function __query_execute(query, execute)
+    -- we use the external arguments here to support lua 5.1 xpcall (which does not support argument passing)
+    -- also, we can not use upvalues directly, because the function may be called recursively in that case
+    -- storing the arguments in local variables makes them invulnerable to changes during recursive calls
+
+    query = query or __query_execute_external_arguments[1]
+    execute = execute or __query_execute_external_arguments[2]
+
+    for chunk, entity_list, entity_count in __evolved_execute(query) do
+        execute(chunk, entity_list, entity_count)
+    end
+end
+
 ---@param system evolved.system
 local function __system_process(system)
     ---@type evolved.query?, evolved.execute?, evolved.prologue?, evolved.epilogue?
@@ -4453,7 +4487,7 @@ local function __system_process(system)
         __QUERY, __EXECUTE, __PROLOGUE, __EPILOGUE)
 
     if prologue then
-        local success, result = __lua_pcall(prologue)
+        local success, result = __lua_xpcall(prologue, __lua_debug_traceback)
 
         if not success then
             __error_fmt('system prologue failed: %s', result)
@@ -4462,8 +4496,9 @@ local function __system_process(system)
 
     if execute then
         __evolved_defer()
-        for chunk, entity_list, entity_count in __evolved_execute(query or system) do
+        do
-            local success, result = __lua_pcall(execute, chunk, entity_list, entity_count)
+            __query_execute_external_arguments[1], __query_execute_external_arguments[2] = query or system, execute
+            local success, result = __lua_xpcall(__query_execute, __lua_debug_traceback, query or system, execute)
 
             if not success then
                 __evolved_cancel()
@@ -4497,7 +4532,7 @@ local function __system_process(system)
     end
 
     if epilogue then
-        local success, result = __lua_pcall(epilogue)
+        local success, result = __lua_xpcall(epilogue, __lua_debug_traceback)
 
         if not success then
             __error_fmt('system epilogue failed: %s', result)