Resolve some phpstan issues

Author: MarkBaker

src/PhpSpreadsheet/Calculation/BinaryComparison.php

@@ -16,26 +16,22 @@ class BinaryComparison
      *
      * @param null|string $str1 First string value for the comparison
      * @param null|string $str2 Second string value for the comparison
-     *
-     * @return int
      */
-    private static function strcmpLowercaseFirst($str1, $str2)
+    private static function strcmpLowercaseFirst($str1, $str2): int
     {
-        $inversedStr1 = StringHelper::strCaseReverse($str1);
-        $inversedStr2 = StringHelper::strCaseReverse($str2);
+        $inversedStr1 = StringHelper::strCaseReverse($str1 ?? '');
+        $inversedStr2 = StringHelper::strCaseReverse($str2 ?? '');
 
-        return strcmp($inversedStr1 ?? '', $inversedStr2 ?? '');
+        return strcmp($inversedStr1, $inversedStr2);
     }
 
     /**
      * PHP8.1 deprecates passing null to strcmp.
      *
      * @param null|string $str1 First string value for the comparison
      * @param null|string $str2 Second string value for the comparison
-     *
-     * @return int
      */
-    private static function strcmpAllowNull($str1, $str2)
+    private static function strcmpAllowNull($str1, $str2): int
     {
         return strcmp($str1 ?? '', $str2 ?? '');
     }
@@ -44,7 +40,7 @@ private static function strcmpAllowNull($str1, $str2)
      * @param mixed $operand1
      * @param mixed $operand2
      */
-    public static function compare($operand1, $operand2, string $operator)
+    public static function compare($operand1, $operand2, string $operator): bool
     {
         //    Simple validate the two operands if they are string values
         if (is_string($operand1) && $operand1 > '' && $operand1[0] == Calculation::FORMULA_STRING_QUOTE) {
@@ -81,18 +77,18 @@ private static function evaluateComparison($operand1, $operand2, string $operato
             //    Equality
             case '=':
                 return self::equal($operand1, $operand2);
-            //    Greater than or equal
-            case '>=':
-                return self::greaterThanOrEqual($operand1, $operand2, $useLowercaseFirstComparison);
-            //    Less than or equal
-            case '<=':
-                return self::lessThanOrEqual($operand1, $operand2, $useLowercaseFirstComparison);
             //    Greater than
             case '>':
                 return self::greaterThan($operand1, $operand2, $useLowercaseFirstComparison);
             //    Less than
             case '<':
                 return self::lessThan($operand1, $operand2, $useLowercaseFirstComparison);
+            //    Greater than or equal
+            case '>=':
+                return self::greaterThanOrEqual($operand1, $operand2, $useLowercaseFirstComparison);
+            //    Less than or equal
+            case '<=':
+                return self::lessThanOrEqual($operand1, $operand2, $useLowercaseFirstComparison);
             //    Inequality
             case '<>':
                 return self::notEqual($operand1, $operand2);