Modify an array variable inside php file with Nikic PhpParser [php]

In the first.php file, I assigned some variables and defined some constant values,

define("CONSTANT1", "cons1value");

$variable1 = "var1value";

$variable2 = array(
    "key1" => "value1",
    "key2" => "value2"
);

I need to change values through the second.php file. That changes may like:

define("CONSTANT1", "cons1value_updated");

$variable1 = "var1value_updated";

$variable2 = array(
    "key1" => "value1_updated",
    "key2" => "value2",
    "key_3_added" => "value3_added"
);

I want to do this job using Nikic PhpParser. I tried this code -

$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);
$prettyPrinter = new PhpParser\PrettyPrinter\Standard;
$traverser = new PhpParser\NodeTraverser;

$source = file_get_contents("first.php");

try {
    $stmts = $parser->parse($source);
    $stmts = $traverser->traverse($stmts);
} catch (Error $error) {
    echo "Parse error: {$error->getMessage()}\n";
    return;
}

foreach ($stmts as $item) {
    if (property_exists($item, "expr")) {
        $Ex = $item->expr;

        if (property_exists($Ex, "var")) {
            if ($Ex->var->name == 'variable2') {
                foreach ($Ex->expr->items as $fetItem) {
                    switch ($fetItem->key->value) {
                        case 'key1':
                            $fetItem->value->name->parts[0] = "value1_updated";
                            break;

                        case 'key2':
                            $fetItem->value->name->parts[0] = "value2_updated";
                            break;
                    }
                }

                $Ex->expr->items[] = [
                    "key3_added" => "value3_added"
                ];
            }
        }
    }
}

Everything is works fine. But in the section,

$Ex->expr->items[] = [
    "key3_added" => "value3_added"
];

I'm getting an error. Any solution ?

Not 100% sure if you are using the same version of the parser, but the problem is that you are adding a simple array element into what is an abstract syntax tree. This should contain a description of the element you want to create rather than the data itself.

With nikic/php-parser 4.10.4, you can use something like...

$Ex->expr->items[] = new ArrayItem(new String_("value 3 added"), new String_("key3_added"));

with the following use statements...

use PhpParser\Node\Expr\ArrayItem;
use PhpParser\Node\Scalar\String_;

As you can see, it's creating an ArrayItem() element with two expressions - both being a simple string containing the value first and then the key.