make dep-less derived behaviour more explicit, move it above is_destroying_effect handling

packages/svelte/src/internal/client/reactivity/deriveds.js

@@ -9,7 +9,8 @@ import {
 	STALE_REACTION,
 	ASYNC,
 	WAS_MARKED,
-	DESTROYED
+	DESTROYED,
+	CLEAN
 } from '#client/constants';
 import {
 	active_reaction,
@@ -33,7 +34,7 @@ import { UNINITIALIZED } from '../../../constants.js';
 import { batch_values, current_batch } from './batch.js';
 import { unset_context } from './async.js';
 import { deferred } from '../../shared/utils.js';
-import { update_derived_status } from './status.js';
+import { set_signal_status, update_derived_status } from './status.js';
 
 /** @type {Effect | null} */
 export let current_async_effect = null;
@@ -356,18 +357,21 @@ export function update_derived(derived) {
 	var value = execute_derived(derived);
 
 	if (!derived.equals(value)) {
+		derived.wv = increment_write_version();
+
 		// in a fork, we don't update the underlying value, just `batch_values`.
 		// the underlying value will be updated when the fork is committed.
 		// otherwise, the next time we get here after a 'real world' state
 		// change, `derived.equals` may incorrectly return `true`
-		//
-		// deriveds with no deps should always update `derived.v`
-		// since they will never change and need the value after fork commits
 		if (!current_batch?.is_fork || derived.deps === null) {
 			derived.v = value;
-		}
 
-		derived.wv = increment_write_version();
+			// deriveds without dependencies should never be recomputed
+			if (derived.deps === null) {
+				set_signal_status(derived, CLEAN);
+				return;
+			}
+		}
 	}
 
 	// don't mark derived clean if we're reading it inside a
@@ -384,9 +388,7 @@ export function update_derived(derived) {
 		if (effect_tracking() || current_batch?.is_fork) {
 			batch_values.set(derived, value);
 		}
-	}
-
-	if (batch_values === null || derived.deps === null) {
+	} else {
 		update_derived_status(derived);
 	}
 }