From 3a69b4c41533757ea0e3c7e293bd41818a833ead Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Sat, 16 Nov 2024 17:10:45 +0000
Subject: [PATCH] fix: ensure inline object literals are correctly serialised
 (#14325)

* fix: ensure inline object literals are correctly serialised

* Apply suggestions from code review

* address feedback

* address feedback

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/wicked-readers-knock.md            |  5 ++++
 .../phases/2-analyze/visitors/shared/utils.js | 27 ++++++++++++++++---
 .../samples/inline-expressions-2/_config.js   | 11 ++++++++
 .../samples/inline-expressions-2/main.svelte  |  6 +++++
 4 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/wicked-readers-knock.md
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/_config.js
 create mode 100644 packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/main.svelte

diff --git a/.changeset/wicked-readers-knock.md b/.changeset/wicked-readers-knock.md
new file mode 100644
index 000000000000..4ec417402f20
--- /dev/null
+++ b/.changeset/wicked-readers-knock.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: treat property accesses of literals as pure
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
index 82356ea619c1..2dec4361c8a0 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js
@@ -1,4 +1,4 @@
-/** @import { AssignmentExpression, Expression, Identifier, Pattern, PrivateIdentifier, Super, UpdateExpression, VariableDeclarator } from 'estree' */
+/** @import { AssignmentExpression, Expression, Literal, Pattern, PrivateIdentifier, Super, UpdateExpression, VariableDeclarator } from 'estree' */
 /** @import { AST, Binding } from '#compiler' */
 /** @import { AnalysisState, Context } from '../../types' */
 /** @import { Scope } from '../../../scope' */
@@ -176,21 +176,42 @@ export function is_safe_identifier(expression, scope) {
 }
 
 /**
- * @param {Expression | Super} node
+ * @param {Expression | Literal | Super} node
  * @param {Context} context
  * @returns {boolean}
  */
 export function is_pure(node, context) {
+	if (node.type === 'Literal') {
+		return true;
+	}
+	if (node.type === 'CallExpression') {
+		if (!is_pure(node.callee, context)) {
+			return false;
+		}
+		for (let arg of node.arguments) {
+			if (!is_pure(arg.type === 'SpreadElement' ? arg.argument : arg, context)) {
+				return false;
+			}
+		}
+		return true;
+	}
 	if (node.type !== 'Identifier' && node.type !== 'MemberExpression') {
 		return false;
 	}
 
-	const left = object(node);
+	/** @type {Expression | Super | null} */
+	let left = node;
+	while (left.type === 'MemberExpression') {
+		left = left.object;
+	}
+
 	if (!left) return false;
 
 	if (left.type === 'Identifier') {
 		const binding = context.state.scope.get(left.name);
 		if (binding === null) return true; // globals are assumed to be safe
+	} else if (is_pure(left, context)) {
+		return true;
 	}
 
 	// TODO add more cases (safe Svelte imports, etc)
diff --git a/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/_config.js b/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/_config.js
new file mode 100644
index 000000000000..1869540b2c55
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/_config.js
@@ -0,0 +1,11 @@
+import { test } from '../../test';
+
+export default test({
+	html: `
+		<p>Without text expression: 7.36</p>
+		<p>With text expression: 7.36</p>
+		<p>With text expression and function call: 7.36</p>
+		<p>With text expression and property access: 4</p>
+		<h1>Hello name!</h1>
+		<p>4</p>`
+});
diff --git a/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/main.svelte b/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/main.svelte
new file mode 100644
index 000000000000..78a325dcc420
--- /dev/null
+++ b/packages/svelte/tests/runtime-legacy/samples/inline-expressions-2/main.svelte
@@ -0,0 +1,6 @@
+<p>Without text expression: 7.36</p>
+<p>With text expression: {7.36}</p>
+<p>With text expression and function call: {(7.36).toLocaleString()}</p>
+<p>With text expression and property access: {"test".length}</p>
+<h1>Hello {('name').toUpperCase().toLowerCase()}!</h1>
+<p>{"test".length}</p>