Invalid Argument Supplied for foreach

Why This Happens

The foreach construct requires an array or an object implementing Traversable. When a variable is null, false, or a scalar type, foreach cannot iterate over it. This often happens when a function that normally returns an array returns null or false on failure.

The Problem

$users = fetchUsers(); // Returns null on failure
foreach ($users as $user) {
    echo $user['name'];
}

The Fix

$users = fetchUsers() ?? [];
foreach ($users as $user) {
    echo $user['name'];
}

Step-by-Step Fix

1. 1

   Check the variable type

   Add var_dump() before the foreach to see what type the variable actually is.

2. 2

   Trace the data source

   Find where the variable is assigned and check if the function can return null, false, or a non-array value.

3. 3

   Default to empty array

   Use the null coalescing operator ?? [] to default to an empty array, or add an is_array() check before the foreach.