JSON update in PHP : duplication - php

Question

I have a strange issue when I'm trying to update a json in my database.
This is my code :
// Update content of user cart
$contentJSON = json_decode($userCart['content'],true);
$newJSONContent;
$wineNotExist = true;
$index = 1;
foreach($contentJSON as $key) {
// Update content if wine is already in user cart
if ($key['wineId'] === $wineId) {
$contentObject->wineId = $wineId;
$contentObject->wineQuantity = $key['wineQuantity'] + $wineQuantity;
$dataIndex = strval($index);
$newJSONContent->$dataIndex = $contentObject;
$wineNotExist = false;
} else {
$contentObject->wineId = $key['wineId'];
$contentObject->wineQuantity = $key['wineQuantity'];
$dataIndex = strval($index);
$newJSONContent->$dataIndex = $contentObject;
}
$index++;
}
if ($wineNotExist) {
$dataKey = strval($index);
$contentObject->wineId = $wineId;
$contentObject->wineQuantity = $wineQuantity;
$newJSONContent->$dataKey = $contentObject;
}
So, I decided to build a new JSON and parse the former; moreover if json not contains the wineId we created a new data input in JSON but this section replaces previous key by the right one and create the right one as you can see in AJAX response here :
Response when it's the same wineId
{
"code": 200,
"status": "success",
"message": "This wine has been added to your cart",
"content": {
"1": {
"wineId": 2,
"wineQuantity": 3
}
},
"index": true
}
Response when wineId is not contains in cart
{
"code": 200,
"status": "success",
"message": "This wine has been added to your cart",
"content": {
"1": {
"wineId": 5,
"wineQuantity": 1
},
"2": {
"wineId": 5,
"wineQuantity": 1
}
},
"index": true
}
I don't understand why the instruction in if replaces previous value, do you have an idea why ?
When I use another variable name for contentObject in if instruction, the code works but why ? Because $contentObject is a local variable in foreach loop
Sorry for my english, I'm French.

Answer 1

It works with this code, so the problem is that $contentObject has the previous value whereas it's a local varibale, is it specific to PHP ?
// Update content of user cart
$contentJSON = json_decode($userCart['content'],true);
$newJSONContent;
$wineNotExist = true;
$index = 1;
foreach($contentJSON as $key) {
// Update content if wine is already in user cart
if ($key['wineId'] === $wineId) {
$contentObject=null;
$contentObject->wineId = $wineId;
$contentObject->wineQuantity = $key['wineQuantity'] + $wineQuantity;
$dataIndex = strval($index);
$newJSONContent->$dataIndex = $contentObject;
$wineNotExist = false;
} else {
$contentObject=null;
$contentObject->wineId = $key['wineId'];
$contentObject->wineQuantity = $key['wineQuantity'];
$dataIndex = strval($index);
$newJSONContent->$dataIndex = $contentObject;
}
$index++;
}
if ($wineNotExist) {
$contentObject=null;
$dataKey = strval($index);
$contentObject->wineId = $wineId;
$contentObject->wineQuantity = $wineQuantity;
$newJSONContent->$dataKey = $contentObject;
}