Question 392514 in Laravel Question posted in
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Variable With Class Object Value Accessed Multiple Time is Unexpected Modified in Laravel

so i have a problem while accessing variable that contain class object as a value, if i call it multiple time, it will change result. here the example:

// declared on the first line
$preparedSpec = Specialization::query();

// call on another line like this
$availableSpecializations = $preparedSpec->pluck('name')->toArray();

// call it again under $availableSpecializations
$specDoesntExist = $preparedSpec->where('id', $spec)->doesntExist();

the problem exists when i do this:

$existedSpecIds = $preparedSpec->whereIn('name', $existed)->get();

expected result of variable $existedSpecIds should return data collection, but return empty array []

i don’t realy understand why this happen, may be some expert can explain? thanks in advanced

sorry for bad english

i have already try to initiate new class instead reusing it on $preparedSpec variable, and of course it works.

and actually i just curious why that happen.

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2

Answers


  1. 0

    Create new query builder for each variable because query builder is mutable

    This should work

    $availableSpecializations = Specialization::query()->pluck('name')->toArray();

$specDoesntExist = Specialization::query()->where('id', $spec)->doesntExist();

$existedSpecIds = Specialization::query()->whereIn('name', $existed)->get();
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  2. 0

    The issue arises from the fact that you’re modifying the same query builder:

    $preparedSpec = Specialization::query();

    instance multiple times, which accumulates all the modifications and affects subsequent calls

    Try this Instead:

    // Initial Query
$preparedSpec = Specialization::query();

// First Call
$availableSpecializations = (clone $preparedSpec)->pluck('name')->toArray();

// Second Call
$specDoesntExist = (clone $preparedSpec)->where('id', $spec)->doesntExist();

// Third Call
$existedSpecIds = (clone $preparedSpec)->whereIn('name', $existed)->get();

    clone will help you create a separate copy of the $preparedSpec query builder for each operation. This ensures that each query remains unaffected by changes made in other queries.

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