PHP 7.2 error: count(): Parameter must be an array or an object that implements Countable

[michaelklopf]

Since switching to PHP 7.2.4, we discovered this problem with our PDF merging tool, that makes use of this library.

Stacktrace:

[2018-04-26 16:40:24] local.ERROR: count(): Parameter must be an array or an object that implements Countable {"userId":123,"email":"test@test.com","exception":"[object] (ErrorException(code: 0): count(): Parameter must be an array or an object that implements Countable at /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi_parser.php:486)
[stacktrace]
#0 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi_parser.php(486): Illuminate\\Foundation\\Bootstrap\\HandleExceptions->handleError(2, 'count(): Parame...', '/Users/username...', 486, Array)
#1 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi_parser.php(356): tcpdi_parser->decodeXrefStream(3979271, Array)
#2 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi_parser.php(195): tcpdi_parser->getXrefData()
#3 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi.php(122): tcpdi_parser->__construct('%PDF-1.6\
%\\xE2\\xE3\\xCF\\xD3\
...', '/Users/username...')
#4 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/tcpdf/tcpdi.php(89): TCPDI->_getPdfParser('/Users/username...')
#5 /Users/username/dev/projectname/vendor/lynx39/lara-pdf-merger/src/LynX39/LaraPdfMerger/PdfManage.php(60): TCPDI->setSourceFile('/Users/username...')
#6 /Users/username/dev/projectname/app/Http/Controllers/ExportController.php(56): LynX39\\LaraPdfMerger\\PdfManage->merge('browser', '123-12-12333223...')
#7 [internal function]: App\\Http\\Controllers\\ExportController->App\\Http\\Controllers\\{closure}()
#8 /Users/username/dev/projectname/vendor/symfony/http-foundation/StreamedResponse.php(114): call_user_func(Object(Closure))
#9 /Users/username/dev/projectname/vendor/symfony/http-foundation/Response.php(367): Symfony\\Component\\HttpFoundation\\StreamedResponse->sendContent()
#10 /Users/username/dev/projectname/public/index.php(58): Symfony\\Component\\HttpFoundation\\Response->send()
#11 /Users/username/.composer/vendor/laravel/valet/server.php(147): require('/Users/username...')
#12 {main}
"}

The line in tcpdi_parser.php is this one:

    } elseif (($key == '/Index') AND ($v[0] == PDF_TYPE_ARRAY AND count($v[1] >= 2))) {

count($v[1] >= 2) is the cause of error here.

PHP 7.2 Backward incompatible changes:

http://php.net/manual/en/migration72.incompatible.php

The count() functions need to be replaced, or the objects used in them need to be Countable.

I don't have a solution to drop here yet. Any ideas, why the count is there?

[canyonwebworks]

I'm not sure you need to replace count() for PHP 7.2, but you could try
} elseif (($key == '/Index') AND ($v[0] == PDF_TYPE_ARRAY AND count($v[1]) >= 2)) {
instead, since it makes more sense.