add tests

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

@@ -239,9 +239,10 @@ export function internal_set(source, value) {
 /**
  * @param {Value} signal
  * @param {number} status should be DIRTY or MAYBE_DIRTY
+ * @param {boolean} [unsafe] mark all reactions for unsafe mutations
  * @returns {void}
  */
-export function mark_reactions(signal, status) {
+export function mark_reactions(signal, status, unsafe = false) {
 	var reactions = signal.reactions;
 	if (reactions === null) return;
 
@@ -253,23 +254,25 @@ export function mark_reactions(signal, status) {
 		var flags = reaction.f;
 
 		// Skip any effects that are already dirty
-		if ((flags & DIRTY) !== 0) continue;
+		if ((flags & DIRTY) !== 0 && !unsafe) continue;
 
 		// In legacy mode, skip the current effect to prevent infinite loops
 		if (!runes && reaction === active_effect) continue;
 
-		// Inspect effects need to run immediately, so that the stack trace makes sense
-		if (DEV && (flags & INSPECT_EFFECT) !== 0) {
+		// Inspect effects need to run immediately, so that the stack trace makes sense.
+		// Skip doing this for the unsafe mutations as they will have already been added
+		// in the unsafe() wrapper
+		if (DEV && !unsafe && (flags & INSPECT_EFFECT) !== 0) {
 			inspect_effects.add(reaction);
 			continue;
 		}
 
 		set_signal_status(reaction, status);
 
-		// If the signal a) was previously clean or b) is an unowned derived, then mark it
-		if ((flags & (CLEAN | UNOWNED)) !== 0) {
+		// If the signal a) was previously clean or b) is an unowned derived then mark it
+		if ((flags & (CLEAN | UNOWNED)) !== 0 || unsafe) {
 			if ((flags & DERIVED) !== 0) {
-				mark_reactions(/** @type {Derived} */ (reaction), MAYBE_DIRTY);
+				mark_reactions(/** @type {Derived} */ (reaction), MAYBE_DIRTY, unsafe);
 			} else {
 				schedule_effect(/** @type {Effect} */ (reaction));
 			}

packages/svelte/src/internal/client/runtime.js

@@ -552,7 +552,7 @@ export function update_effect(effect) {
 		// to ensure consistency of the graph
 		if (unsafe_sources !== null && (effect.f & CLEAN) !== 0) {
 			for (let i = 0; i < /** @type {Source[]} */ (unsafe_sources).length; i++) {
-				mark_reactions(unsafe_sources[i], DIRTY);
+				mark_reactions(unsafe_sources[i], DIRTY, true);
 			}
 		}
 

packages/svelte/tests/signals/test.ts

@@ -781,4 +781,115 @@ describe('signals', () => {
 			assert.equal($.get(count), 0n);
 		};
 	});
+
+	test('unsafe() correctly ensures graph consistency', () => {
+		return () => {
+			const output: any[] = [];
+
+			const destroy = effect_root(() => {
+				const a = state(0);
+				const b = state(0);
+				const c = derived(() => {
+					$.unsafe(() => {
+						set(b, $.get(a) + 1);
+					});
+					return $.get(a);
+				});
+
+				render_effect(() => {
+					output.push('b' + $.get(b));
+				});
+
+				render_effect(() => {
+					output.push('b' + $.get(b), 'c' + $.get(c));
+				});
+
+				flushSync();
+
+				set(a, 1);
+
+				flushSync();
+			});
+
+			destroy();
+
+			assert.deepEqual(output, ['b0', 'b0', 'c0', 'b1', 'b1', 'c0', 'b2', 'c1', 'b2']);
+		};
+	});
+
+	test('unsafe() correctly ensures graph consistency #2', () => {
+		return () => {
+			const output: any[] = [];
+
+			const destroy = effect_root(() => {
+				const a = state(0);
+				const b = state(0);
+				const c = derived(() => {
+					$.unsafe(() => {
+						set(b, $.get(a) + 1);
+					});
+					return $.get(a);
+				});
+				let d = derived(() => $.get(b));
+
+				render_effect(() => {
+					output.push('d' + $.get(d));
+				});
+
+				render_effect(() => {
+					output.push('d' + $.get(d), 'c' + $.get(c));
+				});
+
+				flushSync();
+
+				set(a, 1);
+
+				flushSync();
+			});
+
+			destroy();
+
+			assert.deepEqual(output, ['d0', 'd0', 'c0', 'd1', 'd1', 'c0', 'd2', 'c1', 'd2']);
+		};
+	});
+
+	test('unsafe() correctly ensures graph consistency #3', () => {
+		return () => {
+			const output: any[] = [];
+
+			const destroy = effect_root(() => {
+				const a = state(0);
+				const b = state(0);
+				const c = derived(() => {
+					$.unsafe(() => {
+						set(b, $.get(a) + 1);
+					});
+					return $.get(a);
+				});
+				let d = state(true);
+				let e = derived(() => $.get(b));
+
+				render_effect(() => {
+					if ($.get(d)) {
+						return;
+					}
+					output.push('e' + $.get(e), 'c' + $.get(c));
+				});
+
+				flushSync();
+
+				set(d, false);
+
+				flushSync();
+
+				set(a, 1);
+
+				flushSync();
+			});
+
+			destroy();
+
+			assert.deepEqual(output, ['e0', 'c0', 'e1', 'c0', 'e2', 'c1']);
+		};
+	});
 });