feat: add flag for inner effect tracking

.gitignore

@@ -8,5 +8,6 @@
 node_modules
 *.tsbuildinfo
 *.rbxm
+*.tgz
 .DS_Store
 roblox.d.luau

packages/charm/src/core.luau

@@ -349,7 +349,7 @@ local function effect(fn: (dispose: () -> ()) -> ...(() -> ())?): () -> ()
 		cleanup = nil :: any,
 	}
 	self.cleanup = effectStop(self)
-	if activeSub then
+	if activeSub and config.trackInnerEffects then
 		link(self, activeSub)
 	elseif activeScope then
 		link(self, activeScope)

packages/charm/src/flags.luau

@@ -12,4 +12,8 @@ return {
 	--- Enforces immutability of atoms by deep-freezing table values. Enabled
 	--- if the optimization level is below 2, which is true in studio.
 	frozen = not isO2,
+	--- Whether inner effects should clean up after themselves when their
+	--- parent effect re-runs. This is usually desirable, but can be disabled
+	--- to revert to the old behavior. Defaults to `true`.
+	trackInnerEffects = true,
 }

packages/charm/src/index.d.ts

@@ -13,6 +13,7 @@ export type Equals<T> = (current: T, incoming: T) => boolean;
 export const flags: {
 	strict: boolean;
 	frozen: boolean;
+	trackInnerEffects: boolean;
 };
 
 export function atom<T>(value: T, equals?: Equals<T>): Atom<T>;