fix: less confusing names for inspect errors (#17026)

* fix: less confusing names for inspect errors

* fix

* Update packages/svelte/src/internal/client/dev/inspect.js

* fix

Author: Rich-Harris

.changeset/swift-taxes-shake.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: less confusing names for inspect errors

packages/svelte/src/internal/client/dev/inspect.js

@@ -33,8 +33,17 @@ export function inspect(get_value, inspector, show_stack = false) {
 				inspector(...snap);
 
 				if (!initial) {
+					const stack = get_stack('$inspect(...)');
 					// eslint-disable-next-line no-console
-					console.log(get_stack('UpdatedAt'));
+
+					if (stack) {
+						// eslint-disable-next-line no-console
+						console.groupCollapsed('stack trace');
+						// eslint-disable-next-line no-console
+						console.log(stack);
+						// eslint-disable-next-line no-console
+						console.groupEnd();
+					}
 				}
 			} else {
 				inspector(initial ? 'init' : 'update', ...snap);

packages/svelte/src/internal/client/dev/tracing.js

@@ -179,8 +179,7 @@ export function get_stack(label) {
 	});
 
 	define_property(error, 'name', {
-		// 'Error' suffix is required for stack traces to be rendered properly
-		value: `${label}Error`
+		value: label
 	});
 
 	return /** @type {Error & { stack: string }} */ (error);

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

@@ -53,7 +53,7 @@ export function proxy(value) {
 	var is_proxied_array = is_array(value);
 	var version = source(0);
 
-	var stack = DEV && tracing_mode_flag ? get_stack('CreatedAt') : null;
+	var stack = DEV && tracing_mode_flag ? get_stack('created at') : null;
 	var parent_version = update_version;
 
 	/**

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

@@ -86,7 +86,7 @@ export function derived(fn) {
 	};
 
 	if (DEV && tracing_mode_flag) {
-		signal.created = get_stack('CreatedAt');
+		signal.created = get_stack('created at');
 	}
 
 	return signal;

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

@@ -76,7 +76,7 @@ export function source(v, stack) {
 	};
 
 	if (DEV && tracing_mode_flag) {
-		signal.created = stack ?? get_stack('CreatedAt');
+		signal.created = stack ?? get_stack('created at');
 		signal.updated = null;
 		signal.set_during_effect = false;
 		signal.trace = null;
@@ -186,7 +186,7 @@ export function internal_set(source, value) {
 
 		if (DEV) {
 			if (tracing_mode_flag || active_effect !== null) {
-				const error = get_stack('UpdatedAt');
+				const error = get_stack('updated at');
 
 				if (error !== null) {
 					source.updated ??= new Map();

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

@@ -609,7 +609,7 @@ export function get(signal) {
 			if (!tracking && !untracking && !was_read) {
 				w.await_reactivity_loss(/** @type {string} */ (signal.label));
 
-				var trace = get_stack('TracedAt');
+				var trace = get_stack('traced at');
 				// eslint-disable-next-line no-console
 				if (trace) console.warn(trace);
 			}
@@ -628,7 +628,7 @@ export function get(signal) {
 			if (signal.trace) {
 				signal.trace();
 			} else {
-				trace = get_stack('TracedAt');
+				trace = get_stack('traced at');
 
 				if (trace) {
 					var entry = tracing_expressions.entries.get(signal);

packages/svelte/tests/helpers.js

@@ -201,7 +201,15 @@ export const async_mode = process.env.SVELTE_NO_ASYNC !== 'true';
  * @param {any[]} logs
  */
 export function normalise_inspect_logs(logs) {
-	return logs.map((log) => {
+	/** @type {string[]} */
+	const normalised = [];
+
+	for (const log of logs) {
+		if (log === 'stack trace') {
+			// ignore `console.group('stack trace')` in default `$inspect(...)` output
+			continue;
+		}
+
 		if (log instanceof Error) {
 			const last_line = log.stack
 				?.trim()
@@ -210,11 +218,13 @@ export function normalise_inspect_logs(logs) {
 
 			const match = last_line && /(at .+) /.exec(last_line);
 
-			return match && match[1];
+			if (match) normalised.push(match[1]);
+		} else {
+			normalised.push(log);
 		}
+	}
 
-		return log;
-	});
+	return normalised;
 }
 
 /**

packages/svelte/tests/runtime-runes/samples/async-reactivity-loss-for-await/_config.js

@@ -17,7 +17,7 @@ export default test({
 			'Detected reactivity loss when reading `values[1]`. This happens when state is read in an async function after an earlier `await`'
 		);
 
-		assert.equal(warnings[1].name, 'TracedAtError');
+		assert.equal(warnings[1].name, 'traced at');
 
 		assert.equal(warnings.length, 2);
 	}

packages/svelte/tests/runtime-runes/samples/async-reactivity-loss/_config.js

@@ -20,7 +20,7 @@ export default test({
 			'Detected reactivity loss when reading `b`. This happens when state is read in an async function after an earlier `await`'
 		);
 
-		assert.equal(warnings[1].name, 'TracedAtError');
+		assert.equal(warnings[1].name, 'traced at');
 
 		assert.equal(warnings.length, 2);
 	}