php playing tricks when I send an "8" as an argument - php

Question

I can't understand what the hack is going on with my code))) May be I just need more experience but... Let's get down to business:
I wrote a function which returns an array with some statistic data for my system, all I need is just to specify the arguments as Year, M, D. If I send something like getStatData(2016,07,07) - works fine, But just as i send something with a digit eight - it fails! eg.: getStatData(2016,07,08) Of course I have a file the fn requires, more over It works fine if a specify args as strings ('2016', '07', '08'); But this is ain't cool:D
The function:
function getStatData($y,$m,$d=false){
if(isset($y) && is_numeric($y) && isset($m) && is_numeric($m)){
$m=($m<10)? '0'.$m : $m;
if(isset($d)){
$d=($d<10)? '0'.$d : $d;
$y= 'days/'.$y;
$data = file_get_contents(STATDIR.'/'.$y.'/'.$m.'_'.$d.'.json');
}
else {
$data = file_get_contents(STATDIR.'/'.$y.'_'.$m.'.json');
}
return json_decode($data, true);
}
else return false;
}
Calling...
print_r(getStatData(2016,07,08)); //call with 08
ERROR: file_get_contents(core/statistic/days/2016/07_00.json): failed to open stream: No such file or directory

Answer 1

Numbers with a zero prefix are octal literals, rather than zero padded decimal integers. It seems that invalid octals are silently treated as 0 in PHP 5. You should pass in 7 and 8 in the example you have provided.
In PHP 7 you will get a parse error. E.g. Parse error: Invalid numeric literal in php shell code on line 1.

Answer 2

Pass arguments as string like print_r(getStatData('2016','07','08'));
As a side note use str_pad() function to format month and date to 2 digit value. Instead if isset($d) use if($d)
function getStatData($y,$m,$d=false){
if(isset($y) && is_numeric($y) && isset($m) && is_numeric($m)){
// use str_pad
$m=str_pad($m, 2, '0', STR_PAD_LEFT);
if($d){
// use str_pad
$d=str_pad($d, 2, '0', STR_PAD_LEFT);
$y= 'days/'.$y;
$data = file_get_contents(STATDIR.'/'.$y.'/'.$m.'_'.$d.'.json');
}
else {
$data = file_get_contents(STATDIR.'/'.$y.'_'.$m.'.json');
}
return json_decode($data, true);
}
else return false;
}
print_r(getStatData('2016','07','08'));