Why Product attribute assigned to all attribute set

Question

While creating set of product attributes via program, it gets assigned to existing Product Sets as well as to newly created Product Sets. I don't want to assign those created attribute to any Attribute Set.

Can anyone help me to solve this issue.

Code Used:

       $eavSetup->addAttribute(
        \Magento\Catalog\Model\Product::ENTITY,
        'attribute_id',
        ['type' => 'varchar',
            'backend' => '',
            'frontend' => '',
            'label' => 'Attribute Name',
            'input' => 'text',
            'class' => '',
            'source' => '',
            'global' => \Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface::SCOPE_STORE,
            'visible' => true,
            'required' => false,
            'user_defined' => false,
            'default' => '',
            'searchable' => false,
            'filterable' => false,
            'comparable' => false,
            'visible_on_front' => false,
            'used_in_product_listing' => true,
            'unique' => false

        ]
    );

Answer 1

Pass 'user_defined' => true to stop assigning attribute to any attribute set.

So your final code should look like

$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'attribute_id',
    ['type' => 'varchar',
        'backend' => '',
        'frontend' => '',
        'label' => 'Attribute Name',
        'input' => 'text',
        'class' => '',
        'source' => '',
        'global' => \Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface::SCOPE_STORE,
        'visible' => true,
        'required' => false,
        'user_defined' => true,
        'default' => '',
        'searchable' => false,
        'filterable' => false,
        'comparable' => false,
        'visible_on_front' => false,
        'used_in_product_listing' => true,
        'unique' => false
    ]
);

Explain In Details:

I just debugged into EavSetup.php at vendor/magento/module-eav/Setup/EavSetup.php and found that Magento checks that if group key is not empty or user_defined key is empty then it assigns an attribute to all attribute set.

if (!empty($attr['group']) || empty($attr['user_defined'])) {
    ...
    ...
    foreach ($sets as $set) {
        if (!empty($attr['group'])) {
            $this->addAttributeGroup($entityTypeId, $set['attribute_set_id'], $attr['group']);
            $this->addAttributeToSet(
                $entityTypeId,
                $set['attribute_set_id'],
                $attr['group'],
                $code,
                $sortOrder
            );
        } else {
            $this->addAttributeToSet(
                $entityTypeId,
                $set['attribute_set_id'],
                $this->_generalGroupName,
                $code,
                $sortOrder
            );
        }
    }
}

We should set 'user_defined' => true` to custom attributes. Only Magento system attributes are set to false. System attributes cannot be deleted if you set false to user_defined, your attribute will work as a system attribute.