Throw MalformedRegex for non-compilation error messages, such as inva…

…lid modifier

src/functions.php

@@ -7,12 +7,17 @@ function re_test(string $pattern, string $subject, string $modifiers = null): bo
     $error = \error_get_last();
     if ($error) {
         [$message, $offset] = \explode(' at offset ', $error['message']);
-        $prefix = 'preg_match(): Compilation failed: ';
-        if (\str_starts_with($message, $prefix)) {
-            $errorMessage = \subStr($message, \strLen($prefix));
+        $compilationPrefix = 'preg_match(): Compilation failed: ';
+        if (\str_starts_with($message, $compilationPrefix)) {
+            $errorMessage = \subStr($message, \strLen($compilationPrefix));
             $caret = \str_repeat(' ', $offset) . '^';
             throw new MalformedRegex($errorMessage . "\n\n" . $pattern . "\n" . $caret . "\n");
         }
+        $prefix = 'preg_match(): ';
+        if (\str_starts_with($message, $prefix)) {
+            throw new MalformedRegex(\subStr($message, \strLen($prefix)));
+        }
+        throw new MalformedRegex($error['message']);
     }
     return $pregMatch;
 }

test/FunctionsTest.php

@@ -40,4 +40,16 @@ public function denotedPositionOfSyntaxError(): void {
         $this->expectExceptionMessage('    ^');
         re_test('[a-z', 'word');
     }
+
+    #[Test]
+    public function throwsForInvalidModifier(): void {
+        $this->expectException(MalformedRegex::class);
+        re_test('', '', modifiers:'K');
+    }
+
+    #[Test]
+    public function invalidModifierExceptionMessage(): void {
+        $this->expectExceptionMessage("Unknown modifier 'K'");
+        re_test('', '', modifiers:'K');
+    }
 }