Question

I’m getting a PHP Notice if I set a $_SESSION index without submission.
Wanted to know if there is a workaround?

The Notice:

PHP Notice: Undefined index: bar

PHP

if($validation_condition) {
    $_SESSION['bar'] = 'foo';
}

The validation process stops the form from submitting, saves the form data to a database and reloads the page. The $_SESSION[‘bar’] displays the correct value but I get a Notice in the logs. Wanting to stop the Notice.

Here is the var_dump()

array(1) {
  ["bar"]=>
  string(3) "foo"
}

as you can see it’s getting set.

There is one small difference from my original question, I’m setting it like this

$_SESSION['bar'] .= 'foo';

With the .(dot) concatenation. When I removed it the Notice went away.

SLAP HEAD ON DESK!

Answer 1

one approach is to ensure that $_SESSION['bar'] is set under both conditions:

if ($validation_condition) {
    $_SESSION['bar'] = 'foo';
} else {
    $_SESSION['bar'] = '';
}

Alternatively, in your display code, you can first check for the existence of $_SESSION['bar']:

if (isset($_SESSION['bar'])) {
    echo $_SESSION['bar'];
}