Make liquidSingleQuote work for Twig specific code

src/printer/print/liquid.ts

@@ -34,6 +34,7 @@ import {
   shouldPreserveContent,
   FORCE_FLAT_GROUP_ID,
   last,
+  transformStringQuotes,
 } from '~/printer/utils';
 
 import { printChildren } from '~/printer/print/children';
@@ -47,7 +48,7 @@ const { replaceEndOfLine } = doc.utils as any;
 
 export function printLiquidDrop(
   path: LiquidAstPath,
-  _options: LiquidParserOptions,
+  options: LiquidParserOptions,
   print: LiquidPrinter,
   { leadingSpaceGroupId, trailingSpaceGroupId }: LiquidPrinterArgs,
 ) {
@@ -75,8 +76,11 @@ export function printLiquidDrop(
     ]);
   }
 
+  // Transform quotes in base case markup based on liquidSingleQuote option
+  const markup = transformStringQuotes(node.markup, options.liquidSingleQuote);
+
   // This should probably be better than this but it'll do for now.
-  const lines = markupLines(node.markup);
+  const lines = markupLines(markup);
   if (lines.length > 1) {
     return group([
       '{{',
@@ -88,15 +92,7 @@ export function printLiquidDrop(
     ]);
   }
 
-  return group([
-    '{{',
-    whitespaceStart,
-    ' ',
-    node.markup,
-    ' ',
-    whitespaceEnd,
-    '}}',
-  ]);
+  return group(['{{', whitespaceStart, ' ', markup, ' ', whitespaceEnd, '}}']);
 }
 
 function printNamedLiquidBlockStart(
@@ -267,18 +263,22 @@ function printNamedLiquidBlockStart(
 
 function printLiquidStatement(
   path: AstPath<Extract<LiquidTag, { name: string; markup: string }>>,
-  _options: LiquidParserOptions,
+  options: LiquidParserOptions,
   _print: LiquidPrinter,
   _args: LiquidPrinterArgs,
 ): Doc {
   const node = path.getValue();
+  const transformedMarkup = transformStringQuotes(
+    node.markup,
+    options.liquidSingleQuote,
+  );
   const shouldSkipLeadingSpace =
-    node.markup.trim() === '' ||
-    (node.name === '#' && node.markup.startsWith('#'));
+    transformedMarkup.trim() === '' ||
+    (node.name === '#' && transformedMarkup.startsWith('#'));
   return doc.utils.removeLines([
     node.name,
     shouldSkipLeadingSpace ? '' : ' ',
-    node.markup,
+    transformedMarkup,
   ]);
 }
 
@@ -324,22 +324,9 @@ export function printLiquidBlockStart(
     );
   }
 
-  const lines = markupLines(node.markup);
-
-  if (node.name === 'liquid') {
-    return group([
-      '{%',
-      whitespaceStart,
-      ' ',
-      node.name,
-      indent([hardline, join(hardline, reindent(lines, true))]),
-      hardline,
-      whitespaceEnd,
-      '%}',
-    ]);
-  }
-
+  // For Twig comments ({# ... #}), don't transform quotes - comments should be preserved as-is
   if (node.name === 'twig') {
+    const lines = markupLines(node.markup);
     if (lines.length > 1) {
       return group([
         '{#',
@@ -351,17 +338,36 @@ export function printLiquidBlockStart(
       ]);
     }
 
-    const markup = node.markup;
     return group([
       '{#',
       whitespaceStart,
-      markup ? ` ${markup}` : '',
+      node.markup ? ` ${node.markup}` : '',
       ' ',
       whitespaceEnd,
       '#}',
     ]);
   }
 
+  // Transform quotes in base case markup based on liquidSingleQuote option
+  const transformedMarkup = transformStringQuotes(
+    node.markup,
+    options.liquidSingleQuote,
+  );
+  const lines = markupLines(transformedMarkup);
+
+  if (node.name === 'liquid') {
+    return group([
+      '{%',
+      whitespaceStart,
+      ' ',
+      node.name,
+      indent([hardline, join(hardline, reindent(lines, true))]),
+      hardline,
+      whitespaceEnd,
+      '%}',
+    ]);
+  }
+
   if (lines.length > 1) {
     return group([
       '{%',
@@ -373,13 +379,12 @@ export function printLiquidBlockStart(
     ]);
   }
 
-  const markup = node.markup;
   return group([
     '{%',
     whitespaceStart,
     ' ',
     node.name,
-    markup ? ` ${markup}` : '',
+    transformedMarkup ? ` ${transformedMarkup}` : '',
     ' ',
     whitespaceEnd,
     '%}',

src/printer/utils/string.ts

@@ -65,3 +65,40 @@ export function hasMoreThanOneNewLineBetweenNodes(
   const count = between.match(/\n/g)?.length || 0;
   return count > 1;
 }
+
+/**
+ * Transforms quotes in base case markup strings based on the liquidSingleQuote option.
+ * This handles cases where the parser falls back to storing markup as a raw string
+ * (e.g., Twig function calls like `stimulus_controller('controller-name')`).
+ *
+ * The function replaces quotes while being careful to:
+ * - Not replace quotes that are escaped
+ * - Not replace quotes inside strings that contain the target quote character
+ * - Handle nested quotes properly
+ */
+export function transformStringQuotes(
+  markup: string,
+  liquidSingleQuote: boolean,
+): string {
+  const preferredQuote = liquidSingleQuote ? "'" : '"';
+
+  // Match strings with the non-preferred quote style
+  // This regex matches quoted strings, being careful about escapes
+  const stringRegex = liquidSingleQuote
+    ? /"([^"\\]|\\.)*"/g // Match double-quoted strings
+    : /'([^'\\]|\\.)*'/g; // Match single-quoted strings
+
+  return markup.replace(stringRegex, (match) => {
+    // Get the content without the outer quotes
+    const content = match.slice(1, -1);
+
+    // If the content contains the preferred quote (unescaped), keep original quotes
+    // to avoid breaking the string
+    if (content.includes(preferredQuote)) {
+      return match;
+    }
+
+    // Replace the quotes
+    return preferredQuote + content + preferredQuote;
+  });
+}

test/twig-function-quotes/fixed.liquid

@@ -0,0 +1,23 @@
+It should convert double quotes to single quotes in Twig function calls (base case)
+{{ stimulus_controller('controller-name') }}
+<div class="class name"></div>
+
+It should keep double quotes if the string contains single quotes
+{{ stimulus_controller("it's a name") }}
+
+It should convert double quotes to single quotes in tag base case
+{% set foo = 'bar' %}
+
+It should handle multiple arguments with quotes
+{{ some_function('arg1', 'arg2') }}
+
+It should convert to double quotes when liquidSingleQuote is false
+liquidSingleQuote: false
+{{ stimulus_controller("controller-name") }}
+
+It should keep single quotes if string contains double quotes when liquidSingleQuote is false
+liquidSingleQuote: false
+{{ stimulus_controller('say "hello"') }}
+
+It should not modify HTML attributes within Twig comments
+{# <div class="should-not-change"></div> #}

test/twig-function-quotes/index.liquid

@@ -0,0 +1,23 @@
+It should convert double quotes to single quotes in Twig function calls (base case)
+{{ stimulus_controller("controller-name") }}
+<div class="class name"></div>
+
+It should keep double quotes if the string contains single quotes
+{{ stimulus_controller("it's a name") }}
+
+It should convert double quotes to single quotes in tag base case
+{% set foo = "bar" %}
+
+It should handle multiple arguments with quotes
+{{ some_function("arg1", "arg2") }}
+
+It should convert to double quotes when liquidSingleQuote is false
+liquidSingleQuote: false
+{{ stimulus_controller('controller-name') }}
+
+It should keep single quotes if string contains double quotes when liquidSingleQuote is false
+liquidSingleQuote: false
+{{ stimulus_controller('say "hello"') }}
+
+It should not modify HTML attributes within Twig comments
+{# <div class="should-not-change"></div> #}

test/twig-function-quotes/index.spec.ts

@@ -0,0 +1,6 @@
+import { assertFormattedEqualsFixed } from '../test-helpers';
+import * as path from 'path';
+
+describe(`Unit: ${path.basename(__dirname)}`, () => {
+  assertFormattedEqualsFixed(__dirname);
+});