"Cannot use a scalar value as an array" for undefined values - php

Question

I have the following piece of code:
function Biz_GetAccountsPerMarket($site = "", $cache = true){
if($site == ""){
$site = $_SESSION["sitedirect_current_site"];
}
$aAccounts = Sys_OptionsGet("sys_site/".$site, "account", $cache);
$aAccountInfo = array();
$aVatAccount = Biz_GetVatAccounts($site, $cache);
$aSalesAccount = Biz_GetSalesAccounts($site, $cache);
foreach((array)$aAccounts as $code => $data){
foreach((array)$data["data"] as $market => $aItem){
$aAccountInfo[$market][$code] = $aItem;
$aAccountInfo[$market][$code]["vat"] = $aVatAccount[$aItem["vat_account_code"]]["value"];
$aAccountInfo[$market][$code]["vat_account"] = $aVatAccount[$aItem["vat_account_code"]]["account"];
$aAccountInfo[$market][$code]["sales_account"] = $aSalesAccount[$aItem["sales_account_code"]]["account"];
}
}
return $aAccountInfo;
}
The four innermost lines in the nested loop generates warnings: "Cannot use a scalar value as an array".
Adding lines that initialises $aAccountInfo[$market] and $aAccountInfo[$market][$code] to empty arrays first silences the errors, but this is far from the only place in our code where nested arrays are initialised in this way; and I can't figure out why it is a problem in the first place.
The following code should reproduce the problem; as far as I can tell; but doesn't:
<?php
ini_set('display_errors', '1');
error_reporting(E_ALL | E_STRICT);
$aTest = [];
$aTest['key']['key'] = 'sausage';
If $aItem was a string or false, or any scalar; I could understand what the problem is; but then the warning should only happen for the last three lines, not all four.
There are other weird things happening there, I hope they're all connected. This is the only one I've managed to isolate enough to ask a question about.
Is it possble to set the default value created by array access somehow?
edit:
I've noticed that many strings that are generates have an extraneous "0". This breaks things, like SQL. If empty array values somehow default to "0" or something, that would explain a lot. I have no idea how that could happen though. I'm currently grepping for "register_tick_function"...

Answer 1

You need to check if arrays have the expected keys. Something like this:
$aAccountInfo[$market][$code]["vat"] = isset($aItem["vat_account_code"]) ? (isset($aVatAccount[$aItem["vat_account_code"]]) ? $aVatAccount[$aItem["vat_account_code"]]["value"] : []) : [];

Answer 2

I am afraid your code is wrong
This line
$aAccountInfo[$market][$code] = $aItem;
creates the new occurance containing a SCALAR value and you then try and add a sub array onto that scalar value, hence the error
If you do this instead
$t = array();
$t['item'] = $aItem;
$t["vat"] = $aVatAccount[$aItem["vat_account_code"]]["value"];
$t["vat_account"] = $aVatAccount[$aItem["vat_account_code"]]["account"];
$t["sales_account"] = $aSalesAccount[$aItem["sales_account_code"]]["account"];
$aAccountInfo[$market][$code] = $t;
Then you will get a sub array created with all the values in it;