Is_Array Issue In Codeigniter Form Validation Callback Function - php

Question

I've the following callback function in my codeiginter form validation rule:
function validate_milestone($mileStones, $csrf) {
if(is_array($mileStones)) {
foreach ($mileStones as $value) {
}
}
}
This is the result of var_dump
array (size=3)
0 =>
array (size=3)
'Name' => string 'a' (length=1)
'Amount' => string '50.00' (length=5)
'Type' => string 'AMOUNT' (length=6)
1 =>
array (size=3)
'Name' => string 'b' (length=1)
'Amount' => string '20.00' (length=5)
'Type' => string 'AMOUNT' (length=6)
2 =>
array (size=3)
'Name' => string 'c' (length=1)
'Amount' => string '30.00' (length=5)
'Type' => string 'AMOUNT' (length=6)
If I remove if(is_array()) condition from the above code, then PHP returns a warning of "Invalid argument supplied for foreach". When I used var_dump($mileStones) it gave array type of variable. Then what is the role of this PHP condition in removing the warning?

Answer 1

When you put the is_array() condition, the code block is simply skipped when $mileStones is not an array (which happens in some cases caused by some other portion of your code that you haven't shared here) and as a result the foreach statement is never executed and gets skipped (thus no warning):
if(is_array($mileStones)) {
echo 'This entire block is skipped when $mileStones is not an array.';
foreach ($mileStones as $value) {
}
}
Now when you remove the is_array() check, the foreach loop is executed no matter what and as $mileStones is not an array or is an empty array in some cases, the built-in warning is thrown. Try this to confirm:
if (is_array($mileStones)) {
foreach ($mileStones as $value) {
}
} else {
echo 'Damn, $mileStones is indeed not an array in some weird cases that I need to check now.';
}
Note: In my opinion you should not use the is_array() check as it simply ignores the situation and all the built-in error handling gets skipped - making debugging difficult.