Setup basic Luau analysis (#372)

This sets up the repo with Luau analysis and fixes the initial type errors.

.github/workflows/ci.yml

@@ -10,6 +10,24 @@ on:
     - master
 
 jobs:
+  analyze:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: Roblox/setup-foreman@v1
+        with:
+          version: "^1.0.1"
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Download global Roblox types
+        shell: bash
+        run: curl -O https://raw.githubusercontent.com/JohnnyMorganz/luau-analyze-rojo/master/globalTypes.d.lua
+
+      - name: Analyze
+        shell: bash
+        run: luau-analyze --project=default.project.json --defs=globalTypes.d.lua --defs=testez.d.lua src/
+
   test:
     runs-on: ubuntu-latest
 
@@ -52,6 +70,9 @@ jobs:
         luarocks install luacov
         luarocks install luacov-reporter-lcov
 
+    - name: Install and run darklua
+      run: darklua process src/ src/ --format retain-lines
+
     - name: Test
       run: |
         lua -lluacov bin/spec.lua

.luaurc

@@ -0,0 +1,7 @@
+{
+	"languageMode": "nonstrict",
+	"lint": {
+    "*": true
+  },
+	"lintErrors": true
+}

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased Changes
 * Removed the warning for `setState` on unmounted components to eliminate false positive warnings, matching upstream React ([#323](https://github.com/Roblox/roact/pull/323)).
+* Added Luau analysis to the repository ([#372](https://github.com/Roblox/roact/pull/372))
 
 ## [1.4.2](https://github.com/Roblox/roact/releases/tag/v1.4.2) (October 6th, 2021)
 * Fixed forwardRef doc code referencing React instead of Roact ([#310](https://github.com/Roblox/roact/pull/310)).

foreman.toml

@@ -1,4 +1,6 @@
 [tools]
 rojo = { source = "rojo-rbx/rojo", version = "6.2.0" }
-selene = { source = "Kampfkarren/selene", version = "0.14" }
-stylua = { source = "JohnnyMorganz/StyLua", version = "0.11" }
+selene = { source = "Kampfkarren/selene", version = "0.18" }
+stylua = { source = "JohnnyMorganz/StyLua", version = "0.13" }
+luau-analyze = { source = "JohnnyMorganz/luau-analyze-rojo", version = "0.527" }
+darklua = { gitlab = "seaofvoices/darklua", version = "0.7.0" }

src/Binding.lua

@@ -134,7 +134,7 @@ function BindingInternalApi.join(upstreamBindings)
 				disconnect()
 			end
 
-			disconnects = nil
+			disconnects = nil :: any
 		end
 	end
 

src/Component.lua

@@ -296,6 +296,7 @@ function Component:__mount(reconciler, virtualNode)
 		virtualNode = virtualNode,
 		componentClass = self,
 		lifecyclePhase = ComponentLifecyclePhase.Init,
+		pendingState = nil,
 	}
 
 	local instance = {

src/ElementUtils.lua

@@ -1,3 +1,4 @@
+--!strict
 local Type = require(script.Parent.Type)
 local Symbol = require(script.Parent.Symbol)
 
@@ -16,6 +17,8 @@ local ElementUtils = {}
 ]]
 ElementUtils.UseParentKey = Symbol.named("UseParentKey")
 
+type Iterator<K, V> = ({ [K]: V }, K?) -> (K?, V?)
+type Element = { [any]: any }
 --[[
 	Returns an iterator over the children of an element.
 	`elementOrElements` may be one of:
@@ -37,14 +40,14 @@ ElementUtils.UseParentKey = Symbol.named("UseParentKey")
 
 	If `elementOrElements` is none of the above, this function will throw.
 ]]
-function ElementUtils.iterateElements(elementOrElements)
+function ElementUtils.iterateElements<K>(elementOrElements): (Iterator<K, Element>, any, nil)
 	local richType = Type.of(elementOrElements)
 
 	-- Single child
 	if richType == Type.Element then
 		local called = false
 
-		return function()
+		return function(_, _)
 			if called then
 				return nil
 			else
@@ -57,7 +60,7 @@ function ElementUtils.iterateElements(elementOrElements)
 	local regularType = typeof(elementOrElements)
 
 	if elementOrElements == nil or regularType == "boolean" then
-		return noop
+		return (noop :: any) :: Iterator<K, Element>
 	end
 
 	if regularType == "table" then

src/Symbol.lua

@@ -1,4 +1,4 @@
---!nonstrict
+--!strict
 --[[
 	A 'Symbol' is an opaque marker type.
 

src/Symbol.spec.lua

@@ -11,7 +11,8 @@ return function()
 		it("should coerce to the given name", function()
 			local symbol = Symbol.named("foo")
 
-			expect(tostring(symbol):find("foo")).to.be.ok()
+			local index = tostring(symbol):find("foo")
+			expect(index).to.be.ok()
 		end)
 
 		it("should be unique when constructed", function()

src/assertDeepEqual.lua

@@ -1,3 +1,4 @@
+--!strict
 --[[
 	A utility used to assert that two objects are value-equal recursively. It
 	outputs fairly nicely formatted messages to help diagnose why two objects
@@ -6,7 +7,7 @@
 	This should only be used in tests.
 ]]
 
-local function deepEqual(a, b)
+local function deepEqual(a: any, b: any): (boolean, string?)
 	if typeof(a) ~= typeof(b) then
 		local message = ("{1} is of type %s, but {2} is of type %s"):format(typeof(a), typeof(b))
 		return false, message
@@ -19,7 +20,7 @@ local function deepEqual(a, b)
 			visitedKeys[key] = true
 
 			local success, innerMessage = deepEqual(value, b[key])
-			if not success then
+			if not success and innerMessage then
 				local message = innerMessage
 					:gsub("{1}", ("{1}[%s]"):format(tostring(key)))
 					:gsub("{2}", ("{2}[%s]"):format(tostring(key)))
@@ -32,7 +33,7 @@ local function deepEqual(a, b)
 			if not visitedKeys[key] then
 				local success, innerMessage = deepEqual(value, a[key])
 
-				if not success then
+				if not success and innerMessage then
 					local message = innerMessage
 						:gsub("{1}", ("{1}[%s]"):format(tostring(key)))
 						:gsub("{2}", ("{2}[%s]"):format(tostring(key)))
@@ -42,11 +43,11 @@ local function deepEqual(a, b)
 			end
 		end
 
-		return true
+		return true, nil
 	end
 
 	if a == b then
-		return true
+		return true, nil
 	end
 
 	local message = "{1} ~= {2}"
@@ -56,7 +57,7 @@ end
 local function assertDeepEqual(a, b)
 	local success, innerMessageTemplate = deepEqual(a, b)
 
-	if not success then
+	if not success and innerMessageTemplate then
 		local innerMessage = innerMessageTemplate:gsub("{1}", "first"):gsub("{2}", "second")
 
 		local message = ("Values were not deep-equal.\n%s"):format(innerMessage)

src/assign.spec.lua

@@ -11,7 +11,7 @@ return function()
 	end)
 
 	it("should merge multiple tables onto the given target table", function()
-		local target = {
+		local target: { a: number, b: number, c: number? } = {
 			a = 5,
 			b = 6,
 		}

src/createReconciler.lua

@@ -237,7 +237,7 @@ local function createReconciler(renderer)
 		mount a new virtual node, and return it in this case, while also issuing
 		a warning to the user.
 	]]
-	function updateVirtualNode(virtualNode, newElement, newState)
+	function updateVirtualNode(virtualNode, newElement, newState: { [any]: any }?): { [any]: any }?
 		if config.internalTypeChecks then
 			internalAssert(Type.of(virtualNode) == Type.VirtualNode, "Expected arg #1 to be of type VirtualNode")
 		end

src/createReconciler.spec.lua

@@ -302,7 +302,9 @@ return function()
 			local node = noopReconciler.mountVirtualNode(emptyFragment, nil, "test")
 
 			expect(node).to.be.ok()
-			expect(next(node.children)).to.never.be.ok()
+
+			local nextNode = next(node.children)
+			expect(nextNode).to.never.be.ok()
 		end)
 
 		it("should mount all fragment's children", function()

src/init.spec.lua

@@ -43,7 +43,7 @@ return function()
 			end
 
 			if not success then
-				local existence = typeof(valueType) == "boolean" and "present" or "of type " .. valueType
+				local existence = typeof(valueType) == "boolean" and "present" or "of type " .. tostring(valueType)
 				local message = ("Expected public API member %q to be %s, but instead it was of type %s"):format(
 					tostring(key),
 					existence,

src/strict.lua

@@ -1,16 +1,18 @@
---!nonstrict
-local function strict(t, name)
-	name = name or tostring(t)
+--!strict
+local function strict(t: { [any]: any }, name: string?)
+	-- FIXME Luau: Need to define a new variable since reassigning `name = ...`
+	-- doesn't narrow the type
+	local newName = name or tostring(t)
 
 	return setmetatable(t, {
 		__index = function(_self, key)
-			local message = ("%q (%s) is not a valid member of %s"):format(tostring(key), typeof(key), name)
+			local message = ("%q (%s) is not a valid member of %s"):format(tostring(key), typeof(key), newName)
 
 			error(message, 2)
 		end,
 
 		__newindex = function(_self, key, _value)
-			local message = ("%q (%s) is not a valid member of %s"):format(tostring(key), typeof(key), name)
+			local message = ("%q (%s) is not a valid member of %s"):format(tostring(key), typeof(key), newName)
 
 			error(message, 2)
 		end,

testez.d.lua

@@ -0,0 +1,24 @@
+declare function afterAll(callback: () -> ()): ()
+declare function afterEach(callback: () -> ()): ()
+
+declare function beforeAll(callback: () -> ()): ()
+declare function beforeEach(callback: () -> ()): ()
+
+declare function describe(phrase: string, callback: () -> ()): ()
+declare function describeFOCUS(phrase: string, callback: () -> ()): ()
+declare function fdescribe(phrase: string, callback: () -> ()): ()
+declare function describeSKIP(phrase: string, callback: () -> ()): ()
+declare function xdescribe(phrase: string, callback: () -> ()): ()
+
+declare function expect(value: any): any
+
+declare function FIXME(optionalMessage: string?): ()
+declare function FOCUS(): ()
+declare function SKIP(): ()
+
+declare function it(phrase: string, callback: () -> ()): ()
+declare function itFOCUS(phrase: string, callback: () -> ()): ()
+declare function fit(phrase: string, callback: () -> ()): ()
+declare function itSKIP(phrase: string, callback: () -> ()): ()
+declare function xit(phrase: string, callback: () -> ()): ()
+declare function itFIXME(phrase: string, callback: () -> ()): ()