Make case sensitive modifiers great again

Ref: #2080 (comment)

includes/class-gravityview-merge-tags.php

@@ -6,6 +6,14 @@
  * @since 1.8.4
  */
 class GravityView_Merge_Tags {
+ /**
+ * Microcache for merge tag modifiers.
+ *
+ * @since TBD
+ *
+ * @var array[]
+ */
+ private static $merge_tag_modifiers = [];
 
  /**
  * @since 1.8.4
@@ -20,12 +28,44 @@ public function __construct() {
  * @since 1.8.4
  */
  private function add_hooks() {
-
  /** @see GFCommon::replace_variables_prepopulate */
  add_filter( 'gform_replace_merge_tags', array( 'GravityView_Merge_Tags', 'replace_gv_merge_tags' ), 10, 7 );
 
  // Process after 10 priority
  add_filter( 'gform_merge_tag_filter', array( 'GravityView_Merge_Tags', 'process_modifiers' ), 20, 5 );
+
+ add_filter( 'gform_pre_replace_merge_tags', [ $this, 'cache_merge_tag_modifiers' ] );
+ }
+
+ /**
+ * Caches merge tag modifiers to preserve their case sensitivity.
+ * This is necessary because {@see GFCommon::replace_field_variable()) applies
+ * `strtolower()` to the modifier and causing issues where case is expexted,
+ * such as date formatting (e.g., `format:Y-m-d`).
+ *
+ * @since TBD
+ *
+ * @param string $text Text with merge tags.
+ *
+ * @return string
+ */
+ public function cache_merge_tag_modifiers( $text ) {
+ // Regex pattern taken from GFCommon::replace_variables().
+ preg_match_all( '/{[^{]*?:(\d+(\.\w+)?)(:(.*?))?}/mi', $text, $matches, PREG_SET_ORDER );
+
+ if ( ! $matches ) {
+ return $text;
+ }
+
+ foreach ( $matches as $match ) {
+ $modifier = $match[4] ?? '';
+
+ if ( $modifier ) {
+ self::$merge_tag_modifiers[ strtolower( $modifier ) ] = $modifier;
+ }
+ }
+
+ return $text;
  }
 
  /**
@@ -50,6 +90,9 @@ public static function process_modifiers( $value, $merge_tag, $modifier, $field,
  return $value;
  }
 
+ // Retrieve the original case-sensitive modifier.
+ $modifier = self::$merge_tag_modifiers[ strtolower( $modifier ) ] ?? $modifier;
+
  // matching regex => the value is the method to call to replace the value.
  $gv_modifiers = array(
  'maxwords:(\d+)' => 'modifier_maxwords',