"Cannot use assign-op operators with string offsets" - Laravel

Question

I have an application in Laravel that is taking a chunk of data from the dB and rendering it as JSON. The following line of code is generating the title error:

$decodedData['detail']['is_stem'] = isset($detailData->is_stem) ? $detailData->is_stem : 0;

The error is: Cannot use assign-op operators with string offsets

$decodedData is a larger array that is eventually returned as JSON. It is created thusly:

$decodedData = json_decode($detailData->detail, true);

$detailData is an object that looks like this:

App\CareersDetails Object
(
    [connection:protected] => mysql
    [table:protected] => 
    [primaryKey:protected] => id
    [keyType:protected] => int
    [incrementing] => 1
    [with:protected] => Array
        (
        )

    [withCount:protected] => Array
        (
        )

    [perPage:protected] => 15
    [exists] => 1
    [wasRecentlyCreated] => 
    [attributes:protected] => Array
        (
            [id] => 4
            [code] => 1234
            [title] => StackOverFlow
            [category] => My Category
            [detail] => "Some details in JSON"
            [is_stem] => 1
            [created_at] => 2018-12-28 17:05:15
            [updated_at] => 2018-12-28 17:05:15
        )

    [original:protected] => Array
        (
            [id] => 7
            [code] => 7890
            [title] => StackOverFlowRocks
            [category] => My Category
            [detail] => "Some details in JSON format"
            [is_stem] => 1
            [created_at] => 2018-12-28 17:05:15
            [updated_at] => 2018-12-28 17:05:15
        )

    [changes:protected] => Array
        (
        )

    [casts:protected] => Array
        (
        )

    [dates:protected] => Array
        (
        )

    [dateFormat:protected] => 
    [appends:protected] => Array
        (
        )

    [dispatchesEvents:protected] => Array
        (
        )

    [observables:protected] => Array
        (
        )

    [relations:protected] => Array
        (
        )

    [touches:protected] => Array
        (
        )

    [timestamps] => 1
    [hidden:protected] => Array
        (
        )

    [visible:protected] => Array
        (
        )

    [fillable:protected] => Array
        (
        )

    [guarded:protected] => Array
        (
            [0] => *
        )

)

When I debug using:

print_r($detailData->is_stem);

The system outputs a 1. Hence it is set.

Alternatively, is my $decodedData array at fault?

Update

Thanks to the comments, I noticed my $decodedData is not an array, it is a string.

Hence I dumped

`$detailData->detail`

To my browser page with print_r and ran it via a simple, seperate PHP script:

$payload = "JSON FROM $detailData->detail";
$data = json_decode($payload,true);
$data['detail']['is_stem'] = 1;
print_r($data );

This works. Hence my question is now why does the string dump from print_r work and my Laravel based-app doesn't?

Or, in other words, why is json_decode returning a string in the Laravel App but an Array in the PHP app with the same input?

`$decodedData['detail']` is a string, not an array, so you cannot assign a subkey to it. — aynber, Dec 28 '18 at 18:37
Possible duplicate of [Fatal error: Cannot use assign-op operators with overloaded objects nor string offsets](https://stackoverflow.com/questions/26838247/fatal-error-cannot-use-assign-op-operators-with-overloaded-objects-nor-string-o) — aynber, Dec 28 '18 at 18:38
Thank you @aynber, I updated my question with some additions from your feedback. — Colin, Dec 28 '18 at 18:50
Your latest edit has some syntax errors, so you may want to fix that. What do you mean the Laravel app doesn't work? — aynber, Dec 28 '18 at 18:52
Updated my question to fix the syntax. The issue is from a Laravel App but when I dump the contents of $detailData->detail with print_r to my browser and run it via a simple PHP script, it creates an array as expected. — Colin, Dec 28 '18 at 18:53

score 0 · Answer 1 · answered Dec 28 '18 at 19:07

0

The issue in my instance was my JSON data was double encoded. The fix was:

$decodedData = json_decode(json_decode($detailData->detail), true);

Note, this is not best practice and is a complete oversight on our part so we will be changing this ASAP.

answered Dec 28 '18 at 19:07

Colin

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"Cannot use assign-op operators with string offsets" - Laravel

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