Implement lastCompute (#398)

Author: hatmatty

docs/api-reference/graph/types/graphobject.md

@@ -15,9 +15,10 @@ export type GraphObject = ScopedObject & {
 	dependencySet: {[GraphObject]: unknown},
 	dependentSet: {[GraphObject]: unknown},
 	lastChange: number?,
+	lastCompute: number?,
 	timeliness: "lazy" | "eager",
 	validity: "valid" | "invalid" | "busy",
-	_evaluate: (GraphObject, lastChange: number?) -> boolean
+	_evaluate: (GraphObject) -> boolean
 }
 ```
 
@@ -75,6 +76,16 @@ object.
 The `os.clock()` time of this object's most recent meaningful change, or `nil`
 if the object is newly created.
 
+<h3 markdown>
+	lastCompute
+	<span class="fusiondoc-api-type">
+		: number?
+	</span>
+</h3>
+
+The `os.clock()` time of when this object was most recently computed, or `nil`
+if the object is newly created.
+
 <h3 markdown>
 	timeliness
 	<span class="fusiondoc-api-type">

src/Animation/ExternalTime.luau

@@ -39,6 +39,7 @@ local function ExternalTime(
 			createdAt = createdAt,
 			dependentSet = {},
 			lastChange = nil,
+			lastCompute = nil,
 			scope = scope,
 			validity = "invalid"
 		}, 

src/Animation/Spring.luau

@@ -81,6 +81,7 @@ local function Spring<T>(
 			dependencySet = {},
 			dependentSet = {},
 			lastChange = nil,
+			lastCompute = nil,
 			scope = scope,
 			validity = "invalid",
 			_activeDamping = -1,

src/Animation/Stopwatch.luau

@@ -53,6 +53,7 @@ local function Stopwatch(
 			dependencySet = {},
 			dependentSet = {},
 			lastChange = nil,
+			lastCompute = nil,
 			scope = scope,
 			validity = "invalid",
 			_EXTREMELY_DANGEROUS_usedAsValue = 0,

src/Animation/Tween.luau

@@ -67,6 +67,7 @@ local function Tween<T>(
 			dependencySet = {},
 			dependentSet = {},
 			lastChange = nil,
+			lastCompute = nil,
 			scope = scope,
 			validity = "invalid",
 			_activeDuration = nil,

src/Graph/evaluate.luau

@@ -21,14 +21,14 @@ local function evaluate(
 	if target.validity == "busy" then
 		return External.logError("infiniteLoop")
 	end
-	local firstEvaluation = target.lastChange == nil
+	local firstEvaluation = target.lastCompute == nil or target.lastChange == nil
 	local isInvalid = target.validity == "invalid"
 	if firstEvaluation or isInvalid or forceComputation then
 		local needsComputation = firstEvaluation or forceComputation
 		if not needsComputation then
 			for dependency in target.dependencySet do
 				evaluate(dependency, false)
-				if dependency.lastChange > target.lastChange then
+				if dependency.lastChange > target.lastCompute then
 					needsComputation = true
 					break
 				end
@@ -42,6 +42,7 @@ local function evaluate(
 			end
 			target.validity = "busy"
 			targetMeaningfullyChanged = target:_evaluate() or firstEvaluation
+			target.lastCompute = os.clock()
 		end
 		if targetMeaningfullyChanged then
 			target.lastChange = os.clock()

src/State/Computed.luau

@@ -52,6 +52,7 @@ local function Computed<T, S>(
 			dependencySet = {},
 			dependentSet = {},
 			lastChange = nil,
+			lastCompute = nil,
 			scope = scope,
 			validity = "invalid",
 			_EXTREMELY_DANGEROUS_usedAsValue = nil,

src/State/Value.luau

@@ -37,6 +37,7 @@ local function Value<T>(
 			createdAt = createdAt,
 			dependentSet = {},
 			lastChange = os.clock(),
+			lastCompute = os.clock(),
 			scope = scope,
 			validity = "valid",
 			_EXTREMELY_DANGEROUS_usedAsValue = initialValue

src/Types.luau

@@ -78,6 +78,7 @@ export type GraphObject = ScopedObject & {
 	dependencySet: {[GraphObject]: unknown},
 	dependentSet: {[GraphObject]: unknown},
 	lastChange: number?,
+	lastCompute: number?,
 	timeliness: "lazy" | "eager",
 	validity: "valid" | "invalid" | "busy",
 	_evaluate: (GraphObject) -> boolean

test/Spec/Graph/evaluate.spec.luau

@@ -415,6 +415,7 @@ return function()
 					local seen = {}
 					for _, searchTarget in searchNow do
 						searchTarget.lastChange = -depth
+						searchTarget.lastCompute = -depth
 						searchTarget.validity = if depth == 0 then "valid" else "invalid"
 						for dependent in searchTarget.dependentSet do
 							if seen[dependent] then