Apply some coercive type-hinting

src/PhpSpreadsheet/Calculation/Calculation.php

@@ -3088,7 +3088,7 @@ class Calculation
         }
 
         //    Test whether we have any language data for this language (any locale)
-        if (in_array($language, self::$validLocaleLanguages)) {
+        if (in_array($language, self::$validLocaleLanguages, true)) {
             //    initialise language/locale settings
             self::$localeFunctions = [];
             self::$localeArgumentSeparator = ',';

src/PhpSpreadsheet/Calculation/Functions.php

@@ -152,7 +152,7 @@ class Functions
         if ($condition === '') {
             return '=""';
         }
-        if (!is_string($condition) || !in_array($condition[0], ['>', '<', '='])) {
+        if (!is_string($condition) || !in_array($condition[0], ['>', '<', '='], true)) {
             $condition = self::operandSpecialHandling($condition);
             if (is_bool($condition)) {
                 return '=' . ($condition ? 'TRUE' : 'FALSE');

src/PhpSpreadsheet/Calculation/Information/ErrorValue.php

@@ -47,7 +47,7 @@ class ErrorValue
             return false;
         }
 
-        return in_array($value, ExcelError::$errorCodes) || $value === ExcelError::CALC();
+        return in_array($value, ExcelError::$errorCodes, true) || $value === ExcelError::CALC();
     }
 
     /**

src/PhpSpreadsheet/Calculation/Information/ExcelError.php

@@ -11,7 +11,7 @@ class ExcelError
     /**
      * List of error codes.
      *
-     * @var array
+     * @var array<string, string>
      */
     public static $errorCodes = [
         'null' => '#NULL!',
@@ -60,7 +60,7 @@ class ExcelError
      *
      * @return string #NULL!
      */
-    public static function null()
+    public static function null(): string
     {
         return self::$errorCodes['null'];
     }
@@ -72,7 +72,7 @@ class ExcelError
      *
      * @return string #NUM!
      */
-    public static function NAN()
+    public static function NAN(): string
     {
         return self::$errorCodes['num'];
     }
@@ -84,7 +84,7 @@ class ExcelError
      *
      * @return string #REF!
      */
-    public static function REF()
+    public static function REF(): string
     {
         return self::$errorCodes['reference'];
     }
@@ -100,7 +100,7 @@ class ExcelError
      *
      * @return string #N/A!
      */
-    public static function NA()
+    public static function NA(): string
     {
         return self::$errorCodes['na'];
     }
@@ -112,7 +112,7 @@ class ExcelError
      *
      * @return string #VALUE!
      */
-    public static function VALUE()
+    public static function VALUE(): string
     {
         return self::$errorCodes['value'];
     }
@@ -124,7 +124,7 @@ class ExcelError
      *
      * @return string #NAME?
      */
-    public static function NAME()
+    public static function NAME(): string
     {
         return self::$errorCodes['name'];
     }
@@ -134,7 +134,7 @@ class ExcelError
      *
      * @return string #DIV/0!
      */
-    public static function DIV0()
+    public static function DIV0(): string
     {
         return self::$errorCodes['divisionbyzero'];
     }
@@ -142,9 +142,9 @@ class ExcelError
     /**
      * CALC.
      *
-     * @return string #Not Yet Implemented
+     * @return string #CALC!
      */
-    public static function CALC()
+    public static function CALC(): string
     {
         return '#CALC!';
     }

src/PhpSpreadsheet/Cell/DataType.php

@@ -21,7 +21,7 @@ class DataType
     /**
      * List of error codes.
      *
-     * @var array
+     * @var array<string, int>
      */
     private static $errorCodes = [
         '#NULL!' => 0,
@@ -36,7 +36,7 @@ class DataType
     /**
      * Get list of error codes.
      *
-     * @return array
+     * @return array<string, int>
      */
     public static function getErrorCodes()
     {

src/PhpSpreadsheet/ReferenceHelper.php

@@ -399,7 +399,7 @@ class ReferenceHelper
                 return $highestColumn . $row;
             }, range(1, $highestRow)),
             function ($coordinate) use ($allCoordinates) {
-                return !in_array($coordinate, $allCoordinates);
+                return in_array($coordinate, $allCoordinates, true) === false;
             }
         );
 
@@ -929,7 +929,7 @@ class ReferenceHelper
                 $coordinate = Coordinate::stringFromColumnIndex($j + 1) . $i;
                 $worksheet->removeConditionalStyles($coordinate);
                 if ($worksheet->cellExists($coordinate)) {
-                    $worksheet->getCell($coordinate)->setValueExplicit('', DataType::TYPE_NULL);
+                    $worksheet->getCell($coordinate)->setValueExplicit(null, DataType::TYPE_NULL);
                     $worksheet->getCell($coordinate)->setXfIndex(0);
                 }
             }
@@ -945,7 +945,7 @@ class ReferenceHelper
                 $coordinate = Coordinate::stringFromColumnIndex($i + 1) . $j;
                 $worksheet->removeConditionalStyles($coordinate);
                 if ($worksheet->cellExists($coordinate)) {
-                    $worksheet->getCell($coordinate)->setValueExplicit('', DataType::TYPE_NULL);
+                    $worksheet->getCell($coordinate)->setValueExplicit(null, DataType::TYPE_NULL);
                     $worksheet->getCell($coordinate)->setXfIndex(0);
                 }
             }

src/PhpSpreadsheet/Shared/TimeZone.php

@@ -21,9 +21,9 @@ class TimeZone
      *
      * @return bool Success or failure
      */
-    private static function validateTimeZone($timezoneName)
+    private static function validateTimeZone(string $timezoneName): bool
     {
-        return in_array($timezoneName, DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC));
+        return in_array($timezoneName, DateTimeZone::listIdentifiers(DateTimeZone::ALL_WITH_BC), true);
     }
 
     /**
@@ -33,7 +33,7 @@ class TimeZone
      *
      * @return bool Success or failure
      */
-    public static function setTimeZone($timezoneName)
+    public static function setTimeZone(string $timezoneName): bool
     {
         if (self::validateTimezone($timezoneName)) {
             self::$timezone = $timezoneName;
@@ -49,7 +49,7 @@ class TimeZone
      *
      * @return string Timezone (e.g. 'Europe/London')
      */
-    public static function getTimeZone()
+    public static function getTimeZone(): string
     {
         return self::$timezone;
     }
@@ -63,7 +63,7 @@ class TimeZone
      *
      * @return int Number of seconds for timezone adjustment
      */
-    public static function getTimeZoneAdjustment($timezoneName, $timestamp)
+    public static function getTimeZoneAdjustment(?string $timezoneName, $timestamp): int
     {
         $timezoneName = $timezoneName ?? self::$timezone;
         $dtobj = Date::dateTimeFromTimestamp("$timestamp");

src/PhpSpreadsheet/Writer/Html.php

@@ -1744,7 +1744,7 @@ class Html extends BaseWriter
                 while ($c++ < $e) {
                     $baseCell = $this->isSpannedCell[$sheetIndex][$rowIndex][$c]['baseCell'];
 
-                    if (!in_array($baseCell, $adjustedBaseCells)) {
+                    if (!in_array($baseCell, $adjustedBaseCells, true)) {
                         // subtract rowspan by 1
                         --$this->isBaseCell[$sheetIndex][$baseCell[0]][$baseCell[1]]['rowspan'];
                         $adjustedBaseCells[] = $baseCell;