New Error Reported with Phpstan 1.3 (#2481)

* New Error Reported with Phpstan 1.3

Dependabot opened a number of PRs. Most are successful, but this change is necessary to allow PR #2477 to complete successfully, and that is apparently a necessity for PR #2479.

Phpstan 1.3 objected to:
```php
trigger_error($errorMessage, E_USER_ERROR);
return false;
```
It claims the return statement is unreachable. This isn't precisely true - an error handler might allow the return to be reached. At any rate, I have slightly restructured the code so that Phpstan will not object either with 1.2 or 1.3, which should allow the blocked PRs to succeed. There had been no previous tests for what happens when there is a formula error when suppressFormulaErrors is true.

* Scrutinizer

Didn't like effect of changes which Phpstan liked. Hopefully this will work better.

* Improvement

Eliminate added function.

phpstan-baseline.neon

@@ -160,16 +160,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Calculation/Calculation.php
 
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Calculation\\:\\:raiseFormulaError\\(\\) has no return type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Calculation.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Calculation\\:\\:raiseFormulaError\\(\\) has parameter \\$errorMessage with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Calculation.php
-
 		-
 			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Calculation\\:\\:validateBinaryOperand\\(\\) has no return type specified\\.$#"
 			count: 1

src/PhpSpreadsheet/Calculation/Calculation.php

@@ -5229,15 +5229,22 @@ class Calculation
         return $result;
     }
 
-    // trigger an error, but nicely, if need be
+    /**
-    protected function raiseFormulaError($errorMessage)
+     * Trigger an error, but nicely, if need be.
+     *
+     * @return false
+     */
+    protected function raiseFormulaError(string $errorMessage)
     {
         $this->formulaError = $errorMessage;
         $this->cyclicReferenceStack->clear();
         if (!$this->suppressFormulaErrors) {
             throw new Exception($errorMessage);
         }
-        trigger_error($errorMessage, E_USER_ERROR);
+
+        if (strlen($errorMessage) > 0) {
+            trigger_error($errorMessage, E_USER_ERROR);
+        }
 
         return false;
     }

tests/PhpSpreadsheetTests/Calculation/CalculationErrorTest.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception as CalcException;
+use PHPUnit\Framework\TestCase;
+use Throwable;
+
+class CalculationErrorTest extends TestCase
+{
+    public function testCalculationException(): void
+    {
+        $this->expectException(CalcException::class);
+        $this->expectExceptionMessage('Formula Error:');
+        $calculation = Calculation::getInstance();
+        $result = $calculation->_calculateFormulaValue('=SUM(');
+        self::assertFalse($result);
+    }
+
+    public function testCalculationError(): void
+    {
+        $calculation = Calculation::getInstance();
+        $calculation->suppressFormulaErrors = true;
+        $error = false;
+
+        try {
+            $calculation->_calculateFormulaValue('=SUM(');
+        } catch (Throwable $e) {
+            self::assertSame("Formula Error: Expecting ')'", $e->getMessage());
+            self::assertSame('PHPUnit\\Framework\\Error\\Error', get_class($e));
+            $error = true;
+        }
+        self::assertTrue($error);
+    }
+
+    /**
+     * @param mixed $args
+     */
+    public static function errhandler2(...$args): bool
+    {
+        return $args[0] === E_USER_ERROR;
+    }
+
+    public function testCalculationErrorTrulySuppressed(): void
+    {
+        $calculation = Calculation::getInstance();
+        $calculation->suppressFormulaErrors = true;
+        set_error_handler([self::class, 'errhandler2']);
+        $result = $calculation->_calculateFormulaValue('=SUM(');
+        restore_error_handler();
+        self::assertFalse($result);
+    }
+}