Implement proper async require & error handling

packages/lib/src/globals/require.rs

@@ -1,96 +1,107 @@
 use std::{
     env::{self, current_dir},
+    io,
     path::PathBuf,
-    sync::Arc,
 };
 
 use mlua::prelude::*;
-use os_str_bytes::{OsStrBytes, RawOsStr};
+use tokio::fs;
 
 use crate::utils::table::TableBuilder;
 
 pub fn create(lua: &'static Lua) -> LuaResult<LuaTable> {
-    // Preserve original require behavior if we have a special env var set
+    // Preserve original require behavior if we have a special env var set,
+    // returning an empty table since there are no globals to overwrite
     if env::var_os("LUAU_PWD_REQUIRE").is_some() {
-        // Return an empty table since there are no globals to overwrite
         return TableBuilder::new(lua)?.build_readonly();
     }
+    // Store the current pwd, and make helper functions for path conversions
+    let require_pwd = current_dir()?.to_string_lossy().to_string();
+    let require_info: LuaFunction = lua.named_registry_value("dbg.info")?;
+    let require_error: LuaFunction = lua.named_registry_value("error")?;
+    let require_get_abs_rel_paths = lua
+        .create_function(
+            |_, (require_pwd, require_source, require_path): (String, String, String)| {
+                let mut path_relative_to_pwd = PathBuf::from(
+                    &require_source
+                        .trim_start_matches("[string \"")
+                        .trim_end_matches("\"]"),
+                )
+                .parent()
+                .unwrap()
+                .join(require_path);
+                // Try to normalize and resolve relative path segments such as './' and '../'
+                if let Ok(canonicalized) =
+                    path_relative_to_pwd.with_extension("luau").canonicalize()
+                {
+                    path_relative_to_pwd = canonicalized;
+                }
+                if let Ok(canonicalized) = path_relative_to_pwd.with_extension("lua").canonicalize()
+                {
+                    path_relative_to_pwd = canonicalized;
+                }
+                let absolute = path_relative_to_pwd.to_string_lossy().to_string();
+                let relative = absolute.trim_start_matches(&require_pwd).to_string();
+                Ok((absolute, relative))
+            },
+        )?
+        .bind(require_pwd)?;
     /*
-      Store the current working directory so that we can use it later
-      and remove it from require paths in error messages, showing
-      absolute paths is bad ux and we should try to avoid it
+        We need to get the source file where require was
+        called to be able to do path-relative requires,
+        so we make a small wrapper to do that here, this
+        will then call our actual async require function
 
-      Throughout this function we also take extra care to not perform any lossy
-      conversion and use os strings instead of Rust's utf-8 checked strings,
-      just in case someone out there uses luau with non-utf8 string requires
+        This must be done in lua because due to how our
+        scheduler works mlua can not preserve debug info
     */
-    let pwd = lua.create_string(&current_dir()?.to_raw_bytes())?;
-    lua.set_named_registry_value("pwd", pwd)?;
-    /*
-      Create a new function that fetches the file name from the current thread,
-      sets the luau module lookup path to be the exact script we are looking
-      for, and then runs the original require function with the wanted path
-    */
-    let new_require = lua.create_function(|lua, require_path: LuaString| {
-        let require_pwd: LuaString = lua.named_registry_value("pwd")?;
-        let require_fn: LuaFunction = lua.named_registry_value("require")?;
-        let require_info: LuaFunction = lua.named_registry_value("dbg.info")?;
-        let require_source: LuaString = require_info.call((2, "s"))?;
-        /*
-          Combine the require caller source with the wanted path
-          string to get a final path relative to pwd - it is definitely
-          relative to pwd because Lune will only load files relative to pwd
-        */
-        let raw_pwd_str = RawOsStr::assert_from_raw_bytes(require_pwd.as_bytes());
-        let raw_source = RawOsStr::assert_from_raw_bytes(require_source.as_bytes());
-        let raw_path = RawOsStr::assert_from_raw_bytes(require_path.as_bytes());
-        let mut path_relative_to_pwd = PathBuf::from(
-            &raw_source
-                .trim_start_matches("[string \"")
-                .trim_end_matches("\"]")
-                .to_os_str(),
+    let require_env = TableBuilder::new(lua)?
+        .with_value("loaded", lua.create_table()?)?
+        .with_value("cache", lua.create_table()?)?
+        .with_value("info", require_info)?
+        .with_value("error", require_error)?
+        .with_value("paths", require_get_abs_rel_paths)?
+        .with_async_function("load", load_file)?
+        .build_readonly()?;
+    let require_fn_lua = lua
+        .load(
+            r#"
+            local source = info(2, "s")
+            local absolute, relative = paths(source, ...)
+            if loaded[absolute] ~= true then
+                local first, second = load(absolute, relative)
+                if first == nil or second ~= nil then
+                    error("Module did not return exactly one value")
+                end
+                loaded[absolute] = true
+                cache[absolute] = first
+                return first
+            else
+                return cache[absolute]
+            end
+            "#,
         )
-        .parent()
-        .unwrap()
-        .join(raw_path.to_os_str());
-        // Try to normalize and resolve relative path segments such as './' and '../'
-        if let Ok(canonicalized) = path_relative_to_pwd.with_extension("luau").canonicalize() {
-            path_relative_to_pwd = canonicalized.with_extension("");
-        }
-        if let Ok(canonicalized) = path_relative_to_pwd.with_extension("lua").canonicalize() {
-            path_relative_to_pwd = canonicalized.with_extension("");
-        }
-        if let Ok(stripped) = path_relative_to_pwd.strip_prefix(&raw_pwd_str.to_os_str()) {
-            path_relative_to_pwd = stripped.to_path_buf();
-        }
-        // Create a lossless lua string from the pathbuf and finally call require
-        let raw_path_str = RawOsStr::new(path_relative_to_pwd.as_os_str());
-        let lua_path_str = lua.create_string(raw_path_str.as_raw_bytes());
-        // If the require call errors then we should also replace
-        // the path in the error message to improve user experience
-        let result: LuaResult<_> = require_fn.call::<_, LuaValue>(lua_path_str);
-        match result {
-            Err(LuaError::CallbackError { traceback, cause }) => {
-                let before = format!(
-                    "runtime error: cannot find '{}'",
-                    path_relative_to_pwd.to_str().unwrap()
-                );
-                let after = format!(
-                    "Invalid require path '{}' ({})",
-                    require_path.to_str().unwrap(),
-                    path_relative_to_pwd.to_str().unwrap()
-                );
-                let cause = Arc::new(LuaError::RuntimeError(
-                    cause.to_string().replace(&before, &after),
-                ));
-                Err(LuaError::CallbackError { traceback, cause })
-            }
-            Err(e) => Err(e),
-            Ok(result) => Ok(result),
-        }
-    })?;
-    // Override the original require global with our monkey-patched one
+        .set_name("require")?
+        .set_environment(require_env)?
+        .into_function()?;
     TableBuilder::new(lua)?
-        .with_value("require", new_require)?
+        .with_value("require", require_fn_lua)?
         .build_readonly()
 }
+
+async fn load_file(
+    lua: &Lua,
+    (path_absolute, path_relative): (String, String),
+) -> LuaResult<LuaValue> {
+    // Try to read the wanted file, note that we use bytes instead of reading
+    // to a string since lua scripts are not necessarily valid utf-8 strings
+    match fs::read(&path_absolute).await {
+        Ok(contents) => lua.load(&contents).set_name(path_relative)?.eval(),
+        Err(e) => match e.kind() {
+            io::ErrorKind::NotFound => Err(LuaError::RuntimeError(format!(
+                "No lua module exists at the path '{path_relative}'"
+            ))),
+            _ => Err(LuaError::external(e)),
+        },
+    }
+}

packages/lib/src/globals/top_level.rs

@@ -37,16 +37,21 @@ pub fn create(lua: &'static Lua) -> LuaResult<LuaTable> {
         })?
         .with_function("error", |lua, (arg, level): (LuaValue, Option<u32>)| {
             let error: LuaFunction = lua.named_registry_value("error")?;
-            let multi = arg.to_lua_multi(lua)?;
+            let trace: LuaFunction = lua.named_registry_value("dbg.trace")?;
             error.call((
-                format!(
-                    "{}\n{}",
-                    format_label("error"),
-                    pretty_format_multi_value(&multi)?
-                ),
+                LuaError::CallbackError {
+                    traceback: format!("override traceback:{}", trace.call::<_, String>(())?),
+                    cause: LuaError::external(format!(
+                        "{}\n{}",
+                        format_label("error"),
+                        pretty_format_multi_value(&arg.to_lua_multi(lua)?)?
+                    ))
+                    .into(),
+                },
                 level,
             ))?;
             Ok(())
         })?
+        // TODO: Add an override for tostring that formats errors in a nicer way
         .build_readonly()
 }

packages/lib/src/lib.rs

@@ -118,9 +118,8 @@ impl Lune {
                 let mut got_error = false;
                 loop {
                     let result = sched.resume_queue().await;
-                    // println!("{result}");
                     if let Some(err) = result.get_lua_error() {
-                        eprintln!("{}", pretty_format_luau_error(&err));
+                        eprintln!("{}", pretty_format_luau_error(&err, true));
                         got_error = true;
                     }
                     if result.is_done() {

packages/lib/src/lua/create.rs

@@ -3,29 +3,38 @@ use mlua::prelude::*;
 /*
     - Level 0 is the call to info
     - Level 1 is the load call in create() below where we load this into a function
-    - Level 2 is the call to the scheduler, probably, but we can't know for sure so we start at 2
+    - Level 2 is the call to the trace, which we also want to skip, so start at 3
+
+    Also note that we must match the mlua traceback format here so that we
+    can pattern match and beautify it properly later on when outputting it
 */
 const TRACE_IMPL_LUA: &str = r#"
 local lines = {}
-for level = 2, 2^8 do
+for level = 3, 16 do
+    local parts = {}
     local source, line, name = info(level, "sln")
     if source then
-        if line then
-            if name and #name > 0 then
-                push(lines, format("    Script '%s', Line %d - function %s", source, line, name))
-            else
-                push(lines, format("    Script '%s', Line %d", source, line))
-            end
-        elseif name and #name > 0 then
-            push(lines, format("    Script '%s' - function %s", source, name))
-        else
-            push(lines, format("    Script '%s'", source))
-        end
-    elseif name then
-        push(lines, format("[Lune] - function %s", source, name))
+        push(parts, source)
     else
         break
     end
+    if line == -1 then
+        line = nil
+    end
+    if name and #name <= 0 then
+        name = nil
+    end
+    if line then
+        push(parts, format("%d", line))
+    end
+    if name and #parts > 1 then
+        push(parts, format(" in function '%s'", name))
+    elseif name then
+        push(parts, format("in function '%s'", name))
+    end
+    if #parts > 0 then
+        push(lines, concat(parts, ":"))
+    end
 end
 if #lines > 0 then
     return concat(lines, "\n")
@@ -49,12 +58,20 @@ end
     * `"type"` -> `type`
     * `"typeof"` -> `typeof`
     ---
+    * `"pcall"` -> `pcall`
+    * `"xpcall"` -> `xpcall`
+    ---
+    * `"tostring"` -> `tostring`
+    * `"tonumber"` -> `tonumber`
+    ---
     * `"co.thread"` -> `coroutine.running`
     * `"co.yield"` -> `coroutine.yield`
     * `"co.close"` -> `coroutine.close`
     ---
     * `"dbg.info"` -> `debug.info`
     * `"dbg.trace"` -> `debug.traceback`
+    * `"dbg.iserr"` -> `<custom function>`
+    * `"dbg.makeerr"` -> `<custom function>`
     ---
 */
 pub fn create() -> LuaResult<&'static Lua> {
@@ -72,23 +89,43 @@ pub fn create() -> LuaResult<&'static Lua> {
     lua.set_named_registry_value("error", globals.get::<_, LuaFunction>("error")?)?;
     lua.set_named_registry_value("type", globals.get::<_, LuaFunction>("type")?)?;
     lua.set_named_registry_value("typeof", globals.get::<_, LuaFunction>("typeof")?)?;
+    lua.set_named_registry_value("xpcall", globals.get::<_, LuaFunction>("xpcall")?)?;
+    lua.set_named_registry_value("pcall", globals.get::<_, LuaFunction>("pcall")?)?;
+    lua.set_named_registry_value("tostring", globals.get::<_, LuaFunction>("tostring")?)?;
+    lua.set_named_registry_value("tonumber", globals.get::<_, LuaFunction>("tonumber")?)?;
     lua.set_named_registry_value("co.thread", coroutine.get::<_, LuaFunction>("running")?)?;
     lua.set_named_registry_value("co.yield", coroutine.get::<_, LuaFunction>("yield")?)?;
     lua.set_named_registry_value("co.close", coroutine.get::<_, LuaFunction>("close")?)?;
     lua.set_named_registry_value("dbg.info", debug.get::<_, LuaFunction>("info")?)?;
+    lua.set_named_registry_value("tab.pack", table.get::<_, LuaFunction>("pack")?)?;
+    lua.set_named_registry_value("tab.unpack", table.get::<_, LuaFunction>("unpack")?)?;
+    // Create a function that can be called from lua to check if a value is a mlua error,
+    // this will be used in async environments for proper error handling and throwing, as
+    // well as a function that can be called to make a callback error with a traceback from lua
+    let dbg_is_err_fn =
+        lua.create_function(move |_, value: LuaValue| Ok(matches!(value, LuaValue::Error(_))))?;
+
+    let dbg_make_err_fn = lua.create_function(|_, (cause, traceback): (LuaError, String)| {
+        Ok(LuaError::CallbackError {
+            traceback,
+            cause: cause.into(),
+        })
+    })?;
     // Create a trace function that can be called to obtain a full stack trace from
     // lua, this is not possible to do from rust when using our manual scheduler
-    let trace_env = lua.create_table_with_capacity(0, 1)?;
-    trace_env.set("info", debug.get::<_, LuaFunction>("info")?)?;
-    trace_env.set("push", table.get::<_, LuaFunction>("insert")?)?;
-    trace_env.set("concat", table.get::<_, LuaFunction>("concat")?)?;
-    trace_env.set("format", string.get::<_, LuaFunction>("format")?)?;
-    let trace_fn = lua
+    let dbg_trace_env = lua.create_table_with_capacity(0, 1)?;
+    dbg_trace_env.set("info", debug.get::<_, LuaFunction>("info")?)?;
+    dbg_trace_env.set("push", table.get::<_, LuaFunction>("insert")?)?;
+    dbg_trace_env.set("concat", table.get::<_, LuaFunction>("concat")?)?;
+    dbg_trace_env.set("format", string.get::<_, LuaFunction>("format")?)?;
+    let dbg_trace_fn = lua
         .load(TRACE_IMPL_LUA)
         .set_name("=dbg.trace")?
-        .set_environment(trace_env)?
+        .set_environment(dbg_trace_env)?
         .into_function()?;
-    lua.set_named_registry_value("dbg.trace", trace_fn)?;
+    lua.set_named_registry_value("dbg.trace", dbg_trace_fn)?;
+    lua.set_named_registry_value("dbg.iserr", dbg_is_err_fn)?;
+    lua.set_named_registry_value("dbg.makeerr", dbg_make_err_fn)?;
     // All done
     Ok(lua)
 }

packages/lib/src/lua/ext.rs

@@ -26,9 +26,19 @@ impl LuaAsyncExt for &'static Lua {
         F: 'static + Fn(&'static Lua, A) -> FR,
         FR: 'static + Future<Output = LuaResult<R>>,
     {
+        let async_env_make_err: LuaFunction = self.named_registry_value("dbg.makeerr")?;
+        let async_env_is_err: LuaFunction = self.named_registry_value("dbg.iserr")?;
+        let async_env_trace: LuaFunction = self.named_registry_value("dbg.trace")?;
+        let async_env_error: LuaFunction = self.named_registry_value("error")?;
+        let async_env_unpack: LuaFunction = self.named_registry_value("tab.unpack")?;
         let async_env_thread: LuaFunction = self.named_registry_value("co.thread")?;
         let async_env_yield: LuaFunction = self.named_registry_value("co.yield")?;
         let async_env = TableBuilder::new(self)?
+            .with_value("makeError", async_env_make_err)?
+            .with_value("isError", async_env_is_err)?
+            .with_value("trace", async_env_trace)?
+            .with_value("error", async_env_error)?
+            .with_value("unpack", async_env_unpack)?
             .with_value("thread", async_env_thread)?
             .with_value("yield", async_env_yield)?
             .with_function(
@@ -50,7 +60,12 @@ impl LuaAsyncExt for &'static Lua {
             .load(
                 "
                 resumeAsync(thread(), ...)
-                return yield()
+                local results = { yield() }
+                if isError(results[1]) then
+                    error(makeError(results[1], trace()))
+                else
+                    return unpack(results)
+                end
                 ",
             )
             .set_name("asyncWrapper")?

packages/lib/src/lua/task/scheduler.rs

@@ -225,8 +225,18 @@ impl<'fut> TaskScheduler<'fut> {
         self.guid_running.set(Some(reference.id()));
         let rets = match args_opt_res {
             Some(args_res) => match args_res {
-                Err(err) => Err(err), // FIXME: We need to throw this error in lua to let pcall & friends handle it properly
-                Ok(args) => thread.resume::<_, LuaMultiValue>(args),
+                /*
+                    HACK: Resuming with an error here only works because the Rust
+                    functions that we register and that may return lua errors are
+                    also error-aware and wrapped in a special wrapper that checks
+                    if the returned value is a lua error userdata, then throws it
+
+                    Also note that this only happens for our custom async functions
+                    that may pass errors as arguments when resuming tasks, other
+                    native mlua functions will handle this and dont need wrapping
+                */
+                Err(err) => thread.resume(err),
+                Ok(args) => thread.resume(args),
             },
             None => thread.resume(()),
         };

packages/lib/src/tests.rs

@@ -55,11 +55,14 @@ create_tests! {
     process_env: "process/env",
     process_exit: "process/exit",
     process_spawn: "process/spawn",
-    require_children: "require/tests/children",
-    require_invalid: "require/tests/invalid",
-    require_nested: "require/tests/nested",
-    require_parents: "require/tests/parents",
-    require_siblings: "require/tests/siblings",
+    require_children: "globals/require/tests/children",
+    require_invalid: "globals/require/tests/invalid",
+    require_nested: "globals/require/tests/nested",
+    require_parents: "globals/require/tests/parents",
+    require_siblings: "globals/require/tests/siblings",
+    global_pcall: "globals/pcall",
+    global_type: "globals/type",
+    global_typeof: "globals/typeof",
     stdio_format: "stdio/format",
     stdio_color: "stdio/color",
     stdio_style: "stdio/style",

packages/lib/src/utils/formatting.rs

@@ -1,6 +1,6 @@
 use std::fmt::Write;
 
-use console::{style, Style};
+use console::{colors_enabled, set_colors_enabled, style, Style};
 use lazy_static::lazy_static;
 use mlua::prelude::*;
 
@@ -178,7 +178,7 @@ pub fn pretty_format_value(
             }
         }
         LuaValue::LightUserData(_) => write!(buffer, "{}", COLOR_PURPLE.apply_to("<userdata>"))?,
-        _ => write!(buffer, "{}", STYLE_DIM.apply_to("?"))?,
+        LuaValue::Error(e) => write!(buffer, "{}", pretty_format_luau_error(e, false),)?,
     }
     Ok(())
 }
@@ -200,7 +200,13 @@ pub fn pretty_format_multi_value(multi: &LuaMultiValue) -> LuaResult<String> {
     Ok(buffer)
 }
 
-pub fn pretty_format_luau_error(e: &LuaError) -> String {
+pub fn pretty_format_luau_error(e: &LuaError, colorized: bool) -> String {
+    let previous_colors_enabled = if !colorized {
+        set_colors_enabled(false);
+        Some(colors_enabled())
+    } else {
+        None
+    };
     let stack_begin = format!("[{}]", COLOR_BLUE.apply_to("Stack Begin"));
     let stack_end = format!("[{}]", COLOR_BLUE.apply_to("Stack End"));
     let err_string = match e {
@@ -218,23 +224,33 @@ pub fn pretty_format_luau_error(e: &LuaError) -> String {
             let mut found_stack_begin = false;
             for (index, line) in err_lines.clone().iter().enumerate().rev() {
                 if *line == "stack traceback:" {
-                    err_lines[index] = stack_begin;
+                    err_lines[index] = stack_begin.clone();
                     found_stack_begin = true;
                     break;
                 }
             }
             // Add "Stack End" to the very end of the stack trace for symmetry
             if found_stack_begin {
-                err_lines.push(stack_end);
+                err_lines.push(stack_end.clone());
             }
             err_lines.join("\n")
         }
         LuaError::CallbackError { traceback, cause } => {
             // Find the best traceback (most lines) and the root error message
-            let mut best_trace = traceback;
+            // The traceback may also start with "override traceback:" which
+            // means it was passed from somewhere that wants a custom trace,
+            // so we should then respect that and get the best override instead
+            let mut best_trace: &str = traceback;
             let mut root_cause = cause.as_ref();
+            let mut trace_override = false;
             while let LuaError::CallbackError { cause, traceback } = root_cause {
-                if traceback.lines().count() > best_trace.len() {
+                let is_override = traceback.starts_with("override traceback:");
+                if is_override {
+                    if !trace_override || traceback.lines().count() > best_trace.len() {
+                        best_trace = traceback.strip_prefix("override traceback:").unwrap();
+                        trace_override = true;
+                    }
+                } else if !trace_override && traceback.lines().count() > best_trace.len() {
                     best_trace = traceback;
                 }
                 root_cause = cause;
@@ -242,15 +258,19 @@ pub fn pretty_format_luau_error(e: &LuaError) -> String {
             // If we got a runtime error with an embedded traceback, we should
             // use that instead since it generally contains more information
             if matches!(root_cause, LuaError::RuntimeError(e) if e.contains("stack traceback:")) {
-                pretty_format_luau_error(root_cause)
+                pretty_format_luau_error(root_cause, colorized)
             } else {
                 // Otherwise we format whatever root error we got using
                 // the same error formatting as for above runtime errors
                 format!(
                     "{}\n{}\n{}\n{}",
-                    pretty_format_luau_error(root_cause),
+                    pretty_format_luau_error(root_cause, colorized),
                     stack_begin,
-                    best_trace.strip_prefix("stack traceback:\n").unwrap(),
+                    if best_trace.starts_with("stack traceback:") {
+                        best_trace.strip_prefix("stack traceback:\n").unwrap()
+                    } else {
+                        best_trace
+                    },
                     stack_end
                 )
             }
@@ -269,11 +289,13 @@ pub fn pretty_format_luau_error(e: &LuaError) -> String {
         }
         e => format!("{e}"),
     };
-    let mut err_lines = err_string.lines().collect::<Vec<_>>();
+    // Re-enable colors if they were previously enabled
+    if let Some(true) = previous_colors_enabled {
+        set_colors_enabled(true)
+    }
     // Remove the script path from the error message
     // itself, it can be found in the stack trace
-    // FIXME: This no longer works now that we use
-    // an exact name when our lune script is loaded
+    let mut err_lines = err_string.lines().collect::<Vec<_>>();
     if let Some(first_line) = err_lines.first() {
         if first_line.starts_with("[string \"") {
             if let Some(closing_bracket) = first_line.find("]:") {
@@ -287,6 +309,120 @@ pub fn pretty_format_luau_error(e: &LuaError) -> String {
             }
         }
     }
-    // Merge all lines back together into one string
-    err_lines.join("\n")
+    // Find where the stack trace stars and ends
+    let stack_begin_idx =
+        err_lines.iter().enumerate().find_map(
+            |(i, line)| {
+                if *line == stack_begin {
+                    Some(i)
+                } else {
+                    None
+                }
+            },
+        );
+    let stack_end_idx =
+        err_lines.iter().enumerate().find_map(
+            |(i, line)| {
+                if *line == stack_end {
+                    Some(i)
+                } else {
+                    None
+                }
+            },
+        );
+    // If we have a stack trace, we should transform the formatting from the
+    // default mlua formatting into something more friendly, similar to Roblox
+    if let (Some(idx_start), Some(idx_end)) = (stack_begin_idx, stack_end_idx) {
+        let stack_lines = err_lines
+            .iter()
+            .enumerate()
+            // Filter out stack lines
+            .filter_map(|(idx, line)| {
+                if idx > idx_start && idx < idx_end {
+                    Some(*line)
+                } else {
+                    None
+                }
+            })
+            // Transform from mlua format into friendly format, while also
+            // ensuring that leading whitespace / indentation is consistent
+            .map(transform_stack_line)
+            .collect::<Vec<_>>();
+        fix_error_nitpicks(format!(
+            "{}\n{}\n{}\n{}",
+            err_lines
+                .iter()
+                .take(idx_start)
+                .copied()
+                .collect::<Vec<_>>()
+                .join("\n"),
+            stack_begin,
+            stack_lines.join("\n"),
+            stack_end,
+        ))
+    } else {
+        fix_error_nitpicks(err_string)
+    }
+}
+
+fn transform_stack_line(line: &str) -> String {
+    match (line.find('['), line.find(']')) {
+        (Some(idx_start), Some(idx_end)) => {
+            let name = line[idx_start..idx_end + 1]
+                .trim_start_matches('[')
+                .trim_start_matches("string ")
+                .trim_start_matches('"')
+                .trim_end_matches(']')
+                .trim_end_matches('"');
+            let after_name = &line[idx_end + 1..];
+            let line_num = match after_name.find(':') {
+                Some(lineno_start) => match after_name[lineno_start + 1..].find(':') {
+                    Some(lineno_end) => &after_name[lineno_start + 1..lineno_end + 1],
+                    None => match after_name.contains("in function") {
+                        false => &after_name[lineno_start + 1..],
+                        true => "",
+                    },
+                },
+                None => "",
+            };
+            let func_name = match after_name.find("in function ") {
+                Some(func_start) => after_name[func_start + 12..]
+                    .trim()
+                    .trim_end_matches('\'')
+                    .trim_start_matches('\'')
+                    .trim_start_matches("_G."),
+                None => "",
+            };
+            let mut result = String::new();
+            write!(
+                result,
+                "    Script '{}'",
+                match name {
+                    "C" => "[C]",
+                    name => name,
+                },
+            )
+            .unwrap();
+            if !line_num.is_empty() {
+                write!(result, ", Line {line_num}").unwrap();
+            }
+            if !func_name.is_empty() {
+                write!(result, " - function {func_name}").unwrap();
+            }
+            result
+        }
+        (_, _) => line.to_string(),
+    }
+}
+
+fn fix_error_nitpicks(full_message: String) -> String {
+    full_message
+        // Hacky fix for our custom require appearing as a normal script
+        .replace("'require', Line 5", "'[C]' - function require")
+        .replace("'require', Line 7", "'[C]' - function require")
+        // Fix error calls in custom script chunks coming through
+        .replace(
+            "'[C]' - function error\n    Script '[C]' - function require",
+            "'[C]' - function require",
+        )
 }

tests/globals/pcall.luau

@@ -0,0 +1,39 @@
+local function test(f, ...)
+	local success, message = pcall(f, ...)
+	assert(not success, "Function did not throw an error")
+	assert(type(message) == "userdata", "Pcall did not return a proper error")
+end
+
+-- These are not async but should be pcallable
+
+test(error, "Test error", 2)
+
+-- Net request is async and will throw a DNS error here for the weird address
+
+test(net.request, "https://wxyz.google.com")
+
+-- Net serve is async and will throw an OS error when trying to serve twice on the same port
+
+local handle = net.serve(8080, function()
+	return ""
+end)
+
+task.delay(0, function()
+	handle.stop()
+end)
+
+test(net.serve, 8080, function() end)
+
+local function e()
+	task.spawn(function()
+		task.defer(function()
+			task.delay(0, function()
+				error({
+					Hello = "World",
+				})
+			end)
+		end)
+	end)
+end
+
+task.defer(e)

tests/globals/require/tests/invalid.luau

@@ -5,8 +5,8 @@ local function test(path: string)
 	if success then
 		error(string.format("Invalid require at path '%s' succeeded", path))
 	else
-		message = tostring(message)
-		if string.find(message, string.format("'%s'", path)) == nil then
+		print(message)
+		if string.find(message, string.format("%s'", path)) == nil then
 			error(
 				string.format(
 					"Invalid require did not mention path '%s' in its error message!\nMessage: %s",

tests/globals/type.luau

@@ -0,0 +1,11 @@
+local function f() end
+
+local thread1 = coroutine.create(f)
+local thread2 = task.spawn(f)
+local thread3 = task.defer(f)
+local thread4 = task.delay(0, f)
+
+assert(type(thread1) == "thread", "Calling type() did not return 'thread' after coroutine.create")
+assert(type(thread2) == "thread", "Calling type() did not return 'thread' after task.spawn")
+assert(type(thread3) == "thread", "Calling type() did not return 'thread' after task.defer")
+assert(type(thread4) == "thread", "Calling type() did not return 'thread' after delay")

tests/globals/typeof.luau

@@ -0,0 +1,14 @@
+local function f() end
+
+local thread1 = coroutine.create(f)
+local thread2 = task.spawn(f)
+local thread3 = task.defer(f)
+local thread4 = task.delay(0, f)
+
+assert(
+	typeof(thread1) == "thread",
+	"Calling typeof() did not return 'thread' after coroutine.create"
+)
+assert(typeof(thread2) == "thread", "Calling typeof() did not return 'thread' after task.spawn")
+assert(typeof(thread3) == "thread", "Calling typeof() did not return 'thread' after task.defer")
+assert(typeof(thread4) == "thread", "Calling typeof() did not return 'thread' after delay")