Failing test case using image_tag and tag slot

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 5
 
 ## main
 
+* Raise the error `RedefinedExistingMethodError` when declaring a slot which conflicts with an existing method.
+
+    *Hugo Chantelauze*
+
 * Resolve an issue where slots starting with `call` would cause a `NameError`
 
     *Blake Williams*

docs/index.md

@@ -141,6 +141,7 @@ ViewComponent is built by over a hundred members of the community, including:
 <img src="https://avatars.githubusercontent.com/fsateler?s=64" alt="fsateler" width="32" />
 <img src="https://avatars.githubusercontent.com/fugufish?s=64" alt="fugufish" width="32" />
 <img src="https://avatars.githubusercontent.com/g13ydson?s=64" alt="g13ydson" width="32" />
+<img src="https://avatars.githubusercontent.com/hchtlz?s=64" alt="hchtlz" width="32" />
 <img src="https://avatars.githubusercontent.com/horacio?s=64" alt="horacio" width="32" />
 <img src="https://avatars.githubusercontent.com/horiaradu?s=64" alt="horiaradu" width="32" />
 <img src="https://avatars.githubusercontent.com/jacob-carlborg-apoex?s=64" alt="yykamei" width="32" />

lib/view_component/errors.rb

@@ -129,6 +129,16 @@ def initialize(klass_name, slot_name)
     end
   end
 
+  class RedefinedExistingMethodError < InvalidSlotNameError
+    MESSAGE =
+      "COMPONENT declares a slot named SLOT_NAME, which conflicts with an existing method.\n\n" \
+      "To fix this issue, choose a different slot name."
+
+    def initialize(klass_name, slot_name)
+      super(MESSAGE.gsub("COMPONENT", klass_name.to_s).gsub("SLOT_NAME", slot_name.to_s))
+    end
+  end
+
   class ReservedSingularSlotNameError < InvalidSlotNameError
     MESSAGE =
       "COMPONENT declares a slot named SLOT_NAME, which is a reserved word in the ViewComponent framework.\n\n" \

lib/view_component/slotable.rb

@@ -312,6 +312,11 @@ def validate_singular_slot_name(slot_name)
         raise_if_slot_conflicts_with_call(slot_name)
         raise_if_slot_ends_with_question_mark(slot_name)
         raise_if_slot_registered(slot_name)
+        raise_if_method_exists(slot_name)
+      end
+
+      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_registered(slot_name)
@@ -321,8 +326,10 @@ def raise_if_slot_registered(slot_name)
         end
       end
 
-      def raise_if_slot_ends_with_question_mark(slot_name)
-        raise SlotPredicateNameError.new(name, slot_name) if slot_name.to_s.ends_with?("?")
+      def raise_if_method_exists(slot_name)
+        if instance_methods.include?(slot_name)
+          raise RedefinedExistingMethodError.new(name, slot_name)
+        end
       end
 
       def raise_if_slot_conflicts_with_call(slot_name)

test/sandbox/test/slotable_test.rb

@@ -741,4 +741,24 @@ def test_slot_names_can_start_with_call
       end
     end
   end
+
+  def test_raises_error_on_slot_name_conflicting_with_existing_method_for_renders_one
+    exception = assert_raises ViewComponent::RedefinedExistingMethodError do
+      Class.new(ViewComponent::Base) do
+        renders_one :tag
+      end
+    end
+
+    assert_includes exception.message, "declares a slot named tag"
+  end
+
+  def test_raises_error_on_slot_name_conflicting_with_existing_method_for_renders_many
+    exception = assert_raises ViewComponent::RedefinedExistingMethodError do
+      Class.new(ViewComponent::Base) do
+        renders_many :tags
+      end
+    end
+
+    assert_includes exception.message, "declares a slot named tag"
+  end
 end