Only select the "latest email with patches" based on the extension

Otherwise we'll pick up emails not intendeded to be consumed by
commitfest, and try to download a txt or something else instead of the
latest patch.

Author: dutow

app/controllers/topics_controller.rb

@@ -63,8 +63,7 @@ def show
       load_star_state
     end
 
-    # Check if topic has any patches (for sidebar button)
-    @has_patches = @messages.any? { |msg| msg.attachments.any?(&:patch?) }
+    @has_patches = @messages.any? { |msg| msg.attachments.any?(&:patch_extension?) }
   end
 
   def aware
@@ -141,7 +140,7 @@ def latest_patchset
                            .where(id: Attachment.where(message_id: @topic.messages.select(:id))
                                                 .select(:message_id))
                            .order(created_at: :desc)
-                           .find { |msg| msg.attachments.any?(&:patch?) }
+                           .find { |msg| msg.attachments.any?(&:patch_extension?) }
 
     return head :not_found unless latest_message
 

app/models/attachment.rb

@@ -8,6 +8,10 @@ class Attachment < ApplicationRecord
   def patch?
     file_name&.ends_with?('.patch') || file_name&.ends_with?('.diff') || patch_content?
   end
+
+  def patch_extension?
+    file_name&.ends_with?('.patch') || file_name&.ends_with?('.diff')
+  end
 
   def decoded_body
     Base64.decode64(body) if body.present?

spec/factories/attachments.rb

@@ -24,5 +24,11 @@
       content_type { "text/plain" }
       body { Base64.encode64("diff --git a/src/backend/test.c b/src/backend/test.c\nindex 123..456\n--- a/src/backend/test.c\n+++ b/src/backend/test.c\n@@ -1,3 +1,4 @@\n code\n+new line\n more code") }
     end
+
+    trait :content_based_patch do
+      file_name { "changes.txt" }
+      content_type { "text/plain" }
+      body { Base64.encode64("diff --git a/src/backend/test.c b/src/backend/test.c\nindex 123..456\n--- a/src/backend/test.c\n+++ b/src/backend/test.c\n@@ -1,3 +1,4 @@\n code\n+new line\n more code") }
+    end
   end
 end

spec/requests/topics_spec.rb

@@ -292,6 +292,16 @@ def attach_verified_alias(user, email:, primary: true)
       end
     end
 
+    context "with content-based patches only (no .diff or .patch extension)" do
+      let!(:message) { create(:message, topic: topic, sender: creator) }
+      let!(:attachment) { create(:attachment, :content_based_patch, message: message) }
+
+      it "returns 404" do
+        get latest_patchset_topic_path(topic)
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+
     context "with nonexistent topic" do
       it "returns 404" do
         get latest_patchset_topic_path(id: 99999)