laravel belongsToMany update extra pivot column without any change

[m-derakhshi]

hi
i try to test eloquent relation belongsToMany .
after test, i see updated relation over and over without any data change.

url description: https://stackoverflow.com/questions/74967177/why-laravel-belongstomany-update-extra-pivot-column

check eloquent sync method in file :
vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/Concerns/InteractsWithPivotTable.php

line 92:
$current = $this->getCurrentlyAttachedPivots() ->pluck($this->relatedPivotKey)->all();

line:95:
$records = $this->formatRecordsList($this->parseIds($ids));

line 113:
$changes = array_merge(
$changes, $this->attachNew($records, $current, false)
);

this method can not detect data is dirty or clean because data pluck only ids.

[m-derakhshi]

@imanghafoori1

[adam-james-scg]

Just commenting to second this. I feel like this needs to have a pull request assembled once we figure out a good solution.

@mderakhshi I believe we're having the same issue, but I'd like to be sure. This is the problem I'm having.

If I have this data in my pivot table (connecting a product to categories):

category_id    product_id    type    created_at    updated_at
250            1             'main'  2023-01-01 00:00:00  2023-01-01 00:00:00

I then get a model and sync the same exact IDs plus the same extra pivot data:

$product = Product::find(1);
$synced = $product->categories()->sync([250 => ['type' => 'main']]);

I would expect the result to be no changes to my database tables and I would expect $synced to have three empty arrays for attached, detached, and updated. Instead, The updated_at field gets updated and $synced['updated'] will have an entry.

category_id    product_id    type    created_at    updated_at
250            1             'main'  2023-01-01 00:00:00  2023-01-03 11:09:53

[ 'attached' => [], 'detached' => [], 'updated' => [0 => 250], ]

This behavior makes the return data of the sync method unreliable, causes extra database updates, and pollutes the updated_at field.

This behavior is different than if you didn't include extra pivot data. If this was my data:

category_id    product_id    type    created_at    updated_at
250            1             ''      2023-01-01 00:00:00  2023-01-01 00:00:00

And I synced just an id:

$synced = $product->categories()->sync([250]);

The result would be no updates to the database table and no logged updates in $synced.

[m-derakhshi]

@adam-james-scg
Yes. I also tested this way: " $product->categories()->sync([250]); ", But the type column data if have new row id to sync, type saved null
And if we pass type data column "$product->categories()->sync([250 => ['type' => 'main']]);", the record will be updated again