Merge branch '5.4' into 6.3

* 5.4:
  [Translation] Prevent creating empty keys when key ends with a period
  #51928 Missing translations for Belarusian (be)

Tests/Util/ArrayConverterTest.php

@@ -69,6 +69,34 @@ public static function messagesData()
                     ],
                 ],
             ],
+            [
+                // input
+                [
+                    'foo.' => 'foo.',
+                    '.bar' => '.bar',
+                    'abc.abc' => 'value',
+                    'bcd.bcd.' => 'value',
+                    '.cde.cde.' => 'value',
+                    '.def.def' => 'value',
+                ],
+                // expected output
+                [
+                    'foo.' => 'foo.',
+                    '.bar' => '.bar',
+                    'abc' => [
+                        'abc' => 'value',
+                    ],
+                    'bcd' => [
+                        'bcd.' => 'value',
+                    ],
+                    '.cde' => [
+                        'cde.' => 'value',
+                    ],
+                    '.def' => [
+                        'def' => 'value',
+                    ],
+                ],
+            ],
         ];
     }
 }

Util/ArrayConverter.php

@@ -36,7 +36,7 @@ public static function expandToTree(array $messages): array
         $tree = [];
 
         foreach ($messages as $id => $value) {
-            $referenceToElement = &self::getElementByPath($tree, explode('.', $id));
+            $referenceToElement = &self::getElementByPath($tree, self::getKeyParts($id));
 
             $referenceToElement = $value;
 
@@ -63,6 +63,7 @@ private static function &getElementByPath(array &$tree, array $parts): mixed
                 $elem = &$elem[implode('.', \array_slice($parts, $i))];
                 break;
             }
+
             $parentOfElem = &$elem;
             $elem = &$elem[$part];
         }
@@ -94,4 +95,45 @@ private static function cancelExpand(array &$tree, string $prefix, array $node):
             }
         }
     }
+
+    private static function getKeyParts(string $key)
+    {
+        $parts = explode('.', $key);
+        $partsCount = \count($parts);
+
+        $result = [];
+        $buffer = '';
+
+        foreach ($parts as $index => $part) {
+            if (0 === $index && '' === $part) {
+                $buffer = '.';
+
+                continue;
+            }
+
+            if ($index === $partsCount - 1 && '' === $part) {
+                $buffer .= '.';
+                $result[] = $buffer;
+
+                continue;
+            }
+
+            if (isset($parts[$index + 1]) && '' === $parts[$index + 1]) {
+                $buffer .= $part;
+
+                continue;
+            }
+
+            if ($buffer) {
+                $result[] = $buffer.$part;
+                $buffer = '';
+
+                continue;
+            }
+
+            $result[] = $part;
+        }
+
+        return $result;
+    }
 }