From f66bcf0556638a73c24746406fa04acb7aa82b62 Mon Sep 17 00:00:00 2001
From: Duncan McClean <duncan@duncanmcclean.com>
Date: Fri, 28 Feb 2025 18:20:21 +0000
Subject: [PATCH] Add `statamic.system.localize_dates_in_modifiers` config
 option

---
 config/system.php                        | 13 +++++++++++++
 src/Modifiers/CoreModifiers.php          |  4 ++++
 tests/Modifiers/FormatTest.php           |  8 ++++++++
 tests/Modifiers/FormatTranslatedTest.php |  8 ++++++++
 tests/Modifiers/IsoFormatTest.php        |  8 ++++++++
 5 files changed, 41 insertions(+)

diff --git a/config/system.php b/config/system.php
index 9a80cfb9ae..3ab84d0215 100644
--- a/config/system.php
+++ b/config/system.php
@@ -88,6 +88,19 @@
 
     'display_timezone' => 'UTC',
 
+    /*
+    |--------------------------------------------------------------------------
+    | Localize Dates in Modifiers?
+    |--------------------------------------------------------------------------
+    |
+    | Since Statamic stores dates in UTC, any modifiers you chain onto a date
+    | field will be working with the UTC value. If you'd prefer modifiers to
+    | always use your `display_timezone`, set this to `true`.
+    |
+    */
+
+    'localize_dates_in_modifiers' => false,
+
     /*
     |--------------------------------------------------------------------------
     | Default Character Set
diff --git a/src/Modifiers/CoreModifiers.php b/src/Modifiers/CoreModifiers.php
index 9dda002169..ca97fb24ea 100644
--- a/src/Modifiers/CoreModifiers.php
+++ b/src/Modifiers/CoreModifiers.php
@@ -3218,6 +3218,10 @@ private function carbon($value)
             $value = (is_numeric($value)) ? Date::createFromTimestamp($value, config('app.timezone')) : Date::parse($value);
         }
 
+        if (config('statamic.system.localize_dates_in_modifiers')) {
+            $value->setTimezone(config('statamic.system.display_timezone'));
+        }
+
         return $value;
     }
 
diff --git a/tests/Modifiers/FormatTest.php b/tests/Modifiers/FormatTest.php
index ccd78caed1..78bc8d7c7c 100644
--- a/tests/Modifiers/FormatTest.php
+++ b/tests/Modifiers/FormatTest.php
@@ -22,6 +22,14 @@ public function it_formats_date()
         $this->assertSame('1st January 2025 3:45pm', $this->modify(Carbon::parse('2025-01-01 15:45'), 'jS F Y g:ia'));
     }
 
+    #[Test]
+    public function it_formats_date_and_outputs_in_display_timezone()
+    {
+        config()->set('statamic.system.localize_dates_in_modifiers', true);
+
+        $this->assertSame('1st January 2025 4:45pm', $this->modify(Carbon::parse('2025-01-01 15:45'), 'jS F Y g:ia'));
+    }
+
     public function modify($value, $format)
     {
         return Modify::value($value)->format($format)->fetch();
diff --git a/tests/Modifiers/FormatTranslatedTest.php b/tests/Modifiers/FormatTranslatedTest.php
index 9bcc6752b8..2512074dc7 100644
--- a/tests/Modifiers/FormatTranslatedTest.php
+++ b/tests/Modifiers/FormatTranslatedTest.php
@@ -24,6 +24,14 @@ public function it_formats_date()
         $this->assertSame('Mittwoch 1 Januar 2025, 15:45', $this->modify(Carbon::parse('2025-01-01 15:45'), 'l j F Y, H:i'));
     }
 
+    #[Test]
+    public function it_formats_date_and_outputs_in_display_timezone()
+    {
+        config()->set('statamic.system.localize_dates_in_modifiers', true);
+
+        $this->assertSame('Mittwoch 1 Januar 2025, 16:45', $this->modify(Carbon::parse('2025-01-01 15:45'), 'l j F Y, H:i'));
+    }
+
     public function modify($value, $format)
     {
         return Modify::value($value)->formatTranslated($format)->fetch();
diff --git a/tests/Modifiers/IsoFormatTest.php b/tests/Modifiers/IsoFormatTest.php
index 34957a278e..5f78c66a5e 100644
--- a/tests/Modifiers/IsoFormatTest.php
+++ b/tests/Modifiers/IsoFormatTest.php
@@ -22,6 +22,14 @@ public function it_formats_date()
         $this->assertSame('2025.01.01 15:45', $this->modify(Carbon::parse('2025-01-01 15:45'), 'YYYY.MM.DD HH:mm'));
     }
 
+    #[Test]
+    public function it_formats_date_and_outputs_in_display_timezone()
+    {
+        config()->set('statamic.system.localize_dates_in_modifiers', true);
+
+        $this->assertSame('2025.01.01 16:45', $this->modify(Carbon::parse('2025-01-01 15:45'), 'YYYY.MM.DD HH:mm'));
+    }
+
     public function modify($value, $format)
     {
         return Modify::value($value)->isoFormat($format)->fetch();