fix(no-useless-mustaches): Wrong auto-fix for quoted mustaches (#1140)

Author: ota-meshi

.changeset/wise-fireants-obey.md

@@ -0,0 +1,5 @@
+---
+"eslint-plugin-svelte": patch
+---
+
+fix(no-useless-mustaches): Wrong auto-fix for quoted mustaches

packages/eslint-plugin-svelte/src/rules/no-useless-mustaches.ts

@@ -142,14 +142,21 @@ export default createRule('no-useless-mustaches', {
 							node.parent.key.range[1],
 							node.parent.value[0].range[0]
 						);
-						if (!div.endsWith('"') && !div.endsWith("'")) {
+						const quote = div.endsWith('"') ? 'quot' : div.endsWith("'") ? 'apos' : null;
+						if (!quote) {
 							return [
 								fixer.insertTextBefore(node.parent.value[0], '"'),
 								fixer.replaceText(node, unescaped.replace(/"/gu, '"')),
 								fixer.insertTextAfter(node.parent.value[node.parent.value.length - 1], '"')
 							];
 						}
-						return fixer.replaceText(node, unescaped);
+
+						return fixer.replaceText(
+							node,
+							quote === 'quot'
+								? unescaped.replace(/"/gu, '"')
+								: unescaped.replace(/'/gu, ''')
+						);
 					}
 					return fixer.replaceText(node, unescaped.replace(/</gu, '&lt;').replace(/>/gu, '&gt;'));
 				}

packages/eslint-plugin-svelte/tests/fixtures/rules/no-useless-mustaches/invalid/quote-test02-errors.yaml

@@ -0,0 +1,16 @@
+- message: Unexpected mustache interpolation with a string literal value.
+  line: 2
+  column: 17
+  suggestions: null
+- message: Unexpected mustache interpolation with a string literal value.
+  line: 4
+  column: 17
+  suggestions: null
+- message: Unexpected mustache interpolation with a string literal value.
+  line: 6
+  column: 17
+  suggestions: null
+- message: Unexpected mustache interpolation with a string literal value.
+  line: 8
+  column: 17
+  suggestions: null

packages/eslint-plugin-svelte/tests/fixtures/rules/no-useless-mustaches/invalid/quote-test02-input.svelte

@@ -0,0 +1,8 @@
+<!--prettier-ignore-->
+<div data-text="{'\'"'}" />
+<!--prettier-ignore-->
+<div data-text="{"'\""}" />
+<!--prettier-ignore-->
+<div data-text='{'\'"'}' />
+<!--prettier-ignore-->
+<div data-text='{"'\""}' />

packages/eslint-plugin-svelte/tests/fixtures/rules/no-useless-mustaches/invalid/quote-test02-output.svelte

@@ -0,0 +1,8 @@
+<!--prettier-ignore-->
+<div data-text="'&quot;" />
+<!--prettier-ignore-->
+<div data-text="'&quot;" />
+<!--prettier-ignore-->
+<div data-text='&apos;"' />
+<!--prettier-ignore-->
+<div data-text='&apos;"' />