[11.x] incrementEach and decrementEach on a model instance should only update the same record in database

[ebbbang]

incrementEach() and decrementEach() on a model instance will only update the same record in the database.

$user = User::where('shop_id', 1)->first();
$user->decrementEach(['counter' => 1, 'balance' => 100]);
// counter and balance of $user will be decremented.
// All other records will not change.

Please note that the expected behavior of Illuminate\Database\Eloquent\Model, Illuminate\Database\Query\Builder, and Illuminate\Database\Eloquent\Builder is unchanged.

// Decrements all record's counter and balance
User::decrementEach(['counter' => 1, 'balance' => 100]);
DB::table('users')->decrementEach(['counter' => 1, 'balance' => 100]);

// Decrements only user with shop_id = 1
User::where('shop_id', 1)->decrementEach(['counter' => 1, 'balance' => 100]);
DB::table('users')->where('shop_id', 1)->decrementEach(['counter' => 1, 'balance' => 100]);

Related: #49009, #45577 and #48595.

[taylorotwell]

I am closing this pull request because it lacks sufficient explanation, tests, or both. It is difficult for us to merge pull requests without these things because the change may introduce breaking changes to the framework.

Feel free to re-submit your change with a thorough explanation of the feature and tests - integration tests are preferred over unit tests. Please include it's benefit to end users; the reasons it does not break any existing features; how it makes building web applications easier, etc.

Thanks!