How to check Commerce product type of current line item in Rules? When building a Drupal Commerce rule, I would like to loop over all line items and determine the product type for each line item. I would like to use the product type in a Rules Component to check whether the product is a certain type.

How can I check the line item product type when looping over line items in a Drupal Commerce shopping cart?
If the data about a product are not available when processing a "line item", you can make them available. To do so, use a technique similar to what is explained in my answer to "How to access commerce_product field of line-items using Rules to flag the Commerce Product?", which includes a Rules Component that looks like so:

{ "rules_perform_an_action_on_a_selected_line_item" : {
    "LABEL" : "Perform an action on a selected line item",
    "PLUGIN" : "rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "USES VARIABLES" : { "selected_line_item" : { "label" : "Selected Line Item", "type" : "commerce_line_item" } },
    "IF" : [
      { "entity_has_field" : { "entity" : [ "selected-line-item" ], "field" : "commerce_product" } }
    ],
    "DO" : [
      { "entity_fetch" : {
          "USING" : {
            "type" : "commerce_product",
            "id" : [ "selected-line-item:commerce-product:product-id" ]
          },
          "PROVIDE" : { "entity_fetched" : { "product_fetched" : "Fetched Product" } }
        }
      },
      { "drupal_message" : { "message" : "Some details about this product: Product ID = [product-fetched:product-id], Product SKU = [product-fetched:sku], Product Title = [product-fetched:title], Product Creator = [product-fetched:creator]" } }
    ]
  }
}


Here is a blueprint of what you need to do:


Create a Rules Component, similar to the above Rules Component. Just an import of that Rules Component should be enough (to get started and further improve it as detailed below).
Rework the Drupal Message shown via the last Rules Action in the Rules Component (Starting with "Some details about this product"), e.g. by also using either of these available tokens that seem to be what you're interested in:


[product-fetched:type] - The machine name of the product type.
[product-fetched:type-name] - The human readable name of the product type.

Execute that Rules Component inside your Rules Loop of the rule in which you want to loop over all line items.
Improve the Rules Component from Step 1 by creating whatever additional Rules Action(s) you need. Make sure to place these Rules Action(s) AFTER that Rules Action (in the Rules Component) that performs "Fetch entity by ID".


PS: I assume this question is about D7.