Enable Luau strict mode (#22)

# Problem

The repo is using non-strict which is letting some minor type errors get
through

# Solution

Enabled strict mode via .luaurc and fixed the errors it uncovered for
the Lune scripts and ModuleLoader itself

.luaurc

@@ -1,4 +1,5 @@
 {
+	"languageMode": "strict",
 	"aliases": {
 		"pkg": "./Packages",
 		"root": "./src"

.lune/build.luau

@@ -8,6 +8,7 @@ local watch = require("./lib/watcher/watch")
 local args = parseArgs(process.args)
 
 local target = if args.target then args.target else "prod"
+assert(target == "dev" or target == "prod", `bad value for target (must be one of "dev" or "prod", got "{target}")`)
 
 local function build()
 	run("rm", { "-rf", project.BUILD_PATH })

.lune/lib/findClientSettings.luau

@@ -1,6 +1,6 @@
 local run = require("./run")
 
-local function findClientSettings(os: string)
+local function findClientSettings(os: string): string?
 	if os == "macos" then
 		return "/Applications/RobloxStudio.app/Contents/MacOS/ClientSettings"
 	elseif os == "windows" then

.lune/lib/parseArgs.luau

@@ -1,8 +1,9 @@
 local FLAG_PATTERN = "%-%-(%w+)"
 local FLAG_ALL_IN_ONE_PATTERN = `{FLAG_PATTERN}=(%w+)`
 
-local function parseArgs(args: { string }): { [string]: string | boolean | number }
-	local parsedArgs: { [string]: string } = {}
+local function parseArgs(args: { string })
+	local parsedArgs: { [string]: string | boolean | number } = {}
+
 	local skipNextToken = false
 
 	for index, token in args do
@@ -28,16 +29,14 @@ local function parseArgs(args: { string }): { [string]: string | boolean | numbe
 			if nextToken then
 				-- When processing `--foo` in `--foo --bar` treat it like a boolean
 				if nextToken:match(FLAG_PATTERN) then
-					flagValue = true
+					parsedArgs[flagName] = true
 				else
-					flagValue = nextToken
+					parsedArgs[flagName] = nextToken
 					skipNextToken = true
 				end
 			else
-				flagValue = true
+				parsedArgs[flagName] = true
 			end
-
-			parsedArgs[flagName] = flagValue
 		else
 			error(`something went wrong: {token}`)
 		end

.lune/lib/setFlags.luau

@@ -3,8 +3,10 @@ local run = require("./run")
 
 local function setFlags(os: string)
 	local clientSettings = findClientSettings(os)
-	run("mkdir", { "-p", clientSettings })
-	run("cp", { "-R", "tests/ClientAppSettings.json", clientSettings })
+	if clientSettings then
+		run("mkdir", { "-p", clientSettings })
+		run("cp", { "-R", "tests/ClientAppSettings.json", clientSettings })
+	end
 end
 
 return setFlags

.lune/lib/watcher/watch.luau

@@ -16,7 +16,7 @@ type Options = {
 }
 
 local function watch(options: Options)
-	local prevWatchedFileMetadata: { [string]: string } = {}
+	local prevWatchedFileMetadata: { [string]: fs.Metadata } = {}
 	local watchedFiles = getWatchedFiles(options.filePatterns)
 	local prevWatchedFiles
 

src/ModuleLoader.luau

@@ -1,4 +1,3 @@
-local GoodSignal = require("@pkg/GoodSignal")
 local Janitor = require("@pkg/Janitor")
 
 local bind = require("./bind")
@@ -33,9 +32,10 @@ type ModuleLoaderProps = {
 	_cache: { [string]: CachedModule },
 	_loadstring: typeof(loadstring),
 	_debugInfo: typeof(debug.info),
-	_janitors: { [string]: typeof(Janitor.new()) },
+	_janitors: { [string]: any },
 	_globals: { [any]: any },
 
+	_loadedModuleChangedBindable: BindableEvent,
 	loadedModuleChanged: RBXScriptSignal,
 }
 
@@ -82,6 +82,7 @@ function ModuleLoader.new()
 	self._debugInfo = debug.info
 	self._janitors = {}
 	self._globals = {}
+	self._loadedModuleChangedBindable = Instance.new("BindableEvent")
 
 	--[=[
 		Fired when any ModuleScript required through this class has its ancestry
@@ -104,7 +105,7 @@ function ModuleLoader.new()
 		@prop loadedModuleChanged RBXScriptSignal
 		@within ModuleLoader
 	]=]
-	self.loadedModuleChanged = GoodSignal.new()
+	self.loadedModuleChanged = self._loadedModuleChangedBindable.Event
 
 	return setmetatable(self, ModuleLoader)
 end
@@ -211,6 +212,10 @@ function ModuleLoader:require(module: ModuleScript)
 	local cachedModule = self._cache[module:GetFullName()]
 	local callerPath = getCallerPath()
 
+	if not callerPath then
+		return nil
+	end
+
 	if cachedModule then
 		cachedModule.consumers[callerPath] = true
 		return self:_loadCachedModule(module)
@@ -220,7 +225,8 @@ function ModuleLoader:require(module: ModuleScript)
 	local moduleFn, parseError = self._loadstring(source, module:GetFullName())
 
 	if not moduleFn then
-		error(("Could not parse %s: %s"):format(module:GetFullName(), parseError))
+		local message = if parseError then parseError else "<no error message>"
+		error(`Could not parse {module:GetFullName()}: {message}`)
 	end
 
 	local globals = createTablePassthrough(self._globals)
@@ -236,7 +242,7 @@ function ModuleLoader:require(module: ModuleScript)
 	}
 	self._cache[module:GetFullName()] = newCachedModule
 
-	local env = getEnv(module, globals)
+	local env: any = getEnv(module, globals)
 	env.require = bind(self, self.require)
 	setfenv(moduleFn, env)
 
@@ -312,7 +318,7 @@ function ModuleLoader:clearModule(moduleToClear: ModuleScript)
 	end
 
 	for _, module in modulesToClear do
-		self.loadedModuleChanged:Fire(module)
+		self._loadedModuleChangedBindable:Fire(module)
 	end
 end
 

src/ModuleLoader.spec.luau

@@ -21,7 +21,7 @@ type ModuleTestTree = {
 	[string]: string | ModuleTestTree,
 }
 local testNumber = 0
-local function createModuleTest(tree: ModuleTestTree, parent: Instance?)
+local function createModuleTest(tree: ModuleTestTree, parent: Instance?): any
 	testNumber += 1
 
 	local root = Instance.new("Folder")

src/getCallerPath.luau

@@ -2,7 +2,7 @@ local root = script.Parent
 
 local LOADSTRING_PATH_PATTERN = '%[string "(.*)"%]'
 
-local function getCallerPath()
+local function getCallerPath(): string?
 	local level = 1
 
 	while true do

wally.toml

@@ -16,7 +16,6 @@ include = [
 ]
 
 [dependencies]
-GoodSignal = "stravant/[email protected]"
 Janitor = "howmanysmall/[email protected]"
 
 #[dev-dependencies]