Fix slot names that start with call (#1828)

* Fix slot names that start with call

When a component is registered that starts with `call` the compiler detects it as a template method which is not correct. This changes the compiler to look for `call(_|$)` instead of `call` to avoid this issue.

This means that slots can't (and couldn't) start with `call_` since we still rely on the `call_` naming convention to generate the template methods. To make this more dev friendly, this adds a check that raises an error if a slot name starts with `call_`.

A more long-term fix would be to use some kind of template method container instead of relying on the `call_` naming convention.

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 5
 
 ## main
 
+* Resolve an issue where slots starting with `call` would cause a `NameError`
+
+    *Blake Williams*
+
 * Add `use_helper` API.
 
     *Reegan Viljoen*

lib/view_component/compiler.rb

@@ -219,12 +219,12 @@ def inline_calls
               component_class.included_modules
             )
 
-          view_component_ancestors.flat_map { |ancestor| ancestor.instance_methods(false).grep(/^call/) }.uniq
+          view_component_ancestors.flat_map { |ancestor| ancestor.instance_methods(false).grep(/^call(_|$)/) }.uniq
         end
     end
 
     def inline_calls_defined_on_self
-      @inline_calls_defined_on_self ||= component_class.instance_methods(false).grep(/^call/)
+      @inline_calls_defined_on_self ||= component_class.instance_methods(false).grep(/^call(_|$)/)
     end
 
     def variants

lib/view_component/errors.rb

@@ -104,7 +104,10 @@ class InvalidSlotDefinitionError < BaseError
       "string, or callable (that is proc, lambda, etc)"
   end
 
-  class SlotPredicateNameError < StandardError
+  class InvalidSlotNameError < StandardError
+  end
+
+  class SlotPredicateNameError < InvalidSlotNameError
     MESSAGE =
       "COMPONENT declares a slot named SLOT_NAME, which ends with a question mark.\n\n" \
       "This isn't allowed because the ViewComponent framework already provides predicate " \
@@ -126,7 +129,7 @@ def initialize(klass_name, slot_name)
     end
   end
 
-  class ReservedSingularSlotNameError < StandardError
+  class ReservedSingularSlotNameError < InvalidSlotNameError
     MESSAGE =
       "COMPONENT declares a slot named SLOT_NAME, which is a reserved word in the ViewComponent framework.\n\n" \
       "To fix this issue, choose a different name."
@@ -136,7 +139,7 @@ def initialize(klass_name, slot_name)
     end
   end
 
-  class ReservedPluralSlotNameError < StandardError
+  class ReservedPluralSlotNameError < InvalidSlotNameError
     MESSAGE =
       "COMPONENT declares a slot named SLOT_NAME, which is a reserved word in the ViewComponent framework.\n\n" \
       "To fix this issue, choose a different name."

lib/view_component/slotable.rb

@@ -295,6 +295,7 @@ def validate_plural_slot_name(slot_name)
           raise ReservedPluralSlotNameError.new(name, slot_name)
         end
 
+        raise_if_slot_conflicts_with_call(slot_name)
         raise_if_slot_ends_with_question_mark(slot_name)
         raise_if_slot_registered(slot_name)
       end
@@ -308,6 +309,7 @@ def validate_singular_slot_name(slot_name)
           raise ReservedSingularSlotNameError.new(name, slot_name)
         end
 
+        raise_if_slot_conflicts_with_call(slot_name)
         raise_if_slot_ends_with_question_mark(slot_name)
         raise_if_slot_registered(slot_name)
       end
@@ -322,6 +324,12 @@ def raise_if_slot_registered(slot_name)
       def raise_if_slot_ends_with_question_mark(slot_name)
         raise SlotPredicateNameError.new(name, slot_name) if slot_name.to_s.ends_with?("?")
       end
+
+      def raise_if_slot_conflicts_with_call(slot_name)
+        if slot_name.start_with?("call_")
+          raise InvalidSlotNameError, "Slot cannot start with 'call_'. Please rename #{slot_name}"
+        end
+      end
     end
 
     def get_slot(slot_name)

test/sandbox/test/slotable_test.rb

@@ -719,4 +719,26 @@ def test_slot_with_content_shorthand
 
     assert component.title.content?
   end
+
+  def test_slot_names_cannot_start_with_call_
+    assert_raises ViewComponent::InvalidSlotNameError do
+      Class.new(ViewComponent::Base) do
+        renders_one :call_out_title
+      end
+    end
+
+    assert_raises ViewComponent::InvalidSlotNameError do
+      Class.new(ViewComponent::Base) do
+        renders_many :call_out_titles
+      end
+    end
+  end
+
+  def test_slot_names_can_start_with_call
+    assert_nothing_raised do
+      Class.new(ViewComponent::Base) do
+        renders_one :callhome_et
+      end
+    end
+  end
 end