Merge pull request #460 from preactjs/inspect-signal-hook

src/adapter/shared/hooks.ts

@@ -332,6 +332,10 @@ export function inspectHooks<T extends SharedVNode>(
 				c.constructor.call(dummy, dummy.props, dummy.context);
 			}
 		}
+
+		// Signals need this, otherwise they end up in an incosnistent state
+		const diffedHook = options.diffed;
+		if (diffedHook) diffedHook(vnode as any);
 	} catch (error) {
 		// We don't care about any errors here. We only need
 		// the hook call sites

test-e2e/tests/inspect-signal.test.ts

@@ -105,3 +105,32 @@ test("Dectect signal subscriptions", async ({ page }) => {
 
 	await page.locator("p:has-text('count: 10, double: 20')").waitFor();
 });
+
+// https://github.com/preactjs/preact-devtools/issues/456
+test("Don't crash when signal hook is updated", async ({ page }) => {
+	test.skip(
+		process.env.PREACT_VERSION !== "10",
+		"Signals are not supported in v11 yet.",
+	);
+	const { devtools } = await gotoTest(page, "signals");
+
+	await devtools.click(locateTreeItem("Counter"));
+	await devtools.waitForSelector('[data-testid="props-row"]');
+
+	await devtools.click(
+		'[data-testid="Hooks"] form [data-testid="props-row"]:first-child button',
+	);
+
+	await devtools.waitForSelector(
+		'[data-testid="Hooks"] [data-testid="prop-value"]:has-text("ƒ Signal (0)")',
+	);
+
+	await page.click("button:has-text('Add')");
+	await page.click("button:has-text('Add')");
+
+	await devtools.click(locateTreeItem("Display"));
+	await expect(devtools.locator('[data-testid="Hooks"]')).toHaveCount(0);
+
+	await devtools.click(locateTreeItem("Counter"));
+	await expect(devtools.locator('[data-testid="Hooks"]')).toHaveCount(1);
+});