#419

backend/spec/requests/posts_spec.rb

@@ -253,6 +253,93 @@ RSpec.describe 'Posts API', type: :request do
       end
     end
 
+    context 'with legacy external tag name searches' do
+      let!(:external_tag) { create(:external_tag, id: tag.id, name: 'search_external') }
+      let!(:both_post) do
+        create(:post).tap do |post|
+          PostTag.create!(post:, tag:)
+          PostExternalTag.create!(post:, external_tag:)
+        end
+      end
+
+      before do
+        PostExternalTag.create!(post: miss_post, external_tag:)
+      end
+
+      it 'keeps internal name searches independent of colliding external ids' do
+        get '/posts', params: { tags: tag.name }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(3)
+        expect(json.fetch('posts').map { _1.fetch('id') })
+            .to contain_exactly(post_record.id, hit_post.id, both_post.id)
+      end
+
+      it 'finds posts through PostExternalTag by the qualified legacy name' do
+        get '/posts', params: { tags: 'nico:search_external' }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(2)
+        expect(json.fetch('posts').map { _1.fetch('id') })
+            .to contain_exactly(miss_post.id, both_post.id)
+      end
+
+      [nil, 'all'].each do |match|
+        it "intersects internal and external matches with match=#{ match || 'omitted' }" do
+          params = { tags: "#{ tag.name } nico:search_external" }
+          params[:match] = match if match
+
+          get '/posts', params: params
+
+          expect(response).to have_http_status(:ok)
+          expect(json.fetch('count')).to eq(1)
+          expect(json.fetch('posts').map { _1.fetch('id') }).to eq([both_post.id])
+        end
+      end
+
+      it 'unions internal alias and external matches without duplicate posts' do
+        get '/posts', params: { tags: 'manko nico:search_external', match: 'any' }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(4)
+        expect(json.fetch('posts').map { _1.fetch('id') })
+            .to contain_exactly(post_record.id, hit_post.id, miss_post.id, both_post.id)
+      end
+
+      it 'excludes external matches from an internal tag search' do
+        get '/posts', params: { tags: "#{ tag.name } not:nico:search_external" }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(2)
+        expect(json.fetch('posts').map { _1.fetch('id') })
+            .to contain_exactly(post_record.id, hit_post.id)
+      end
+
+      it 'unions an external match with a negated internal match' do
+        get '/posts', params: { tags: "nico:search_external not:#{ tag.name }", match: 'any' }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(2)
+        expect(json.fetch('posts').map { _1.fetch('id') })
+            .to contain_exactly(miss_post.id, both_post.id)
+      end
+
+      it 'keeps a missing qualified external name empty' do
+        get '/posts', params: { tags: 'nico:missing_search_external' }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('count')).to eq(0)
+        expect(json.fetch('posts')).to be_empty
+      end
+
+      it 'applies the same mixed name search to the existing random endpoint' do
+        get '/posts/random', params: { tags: "#{ tag.name } nico:search_external", match: 'all' }
+
+        expect(response).to have_http_status(:ok)
+        expect(json.fetch('id')).to eq(both_post.id)
+      end
+    end
+
     context 'when tags contain not:' do
       let!(:foo_tag_name) { TagName.create!(name: 'not_spec_foo') }
       let!(:foo_tag) { Tag.create!(tag_name: foo_tag_name, category: :general) }
@@ -2286,7 +2373,8 @@ RSpec.describe 'Posts API', type: :request do
             a_hash_including('post_id' => external_post.id, 'version_no' => 1))
       end
 
-      context 'without an internal Tag with the external id' do
+      # Temporary compatibility shim until the frontend sends external_tag explicitly.
+      context 'with legacy tag fallback and no internal Tag with the external id' do
         let(:external_id) { Tag.maximum(:id).to_i + 10_000 }
 
         it 'falls back to ExternalTag for the legacy tag parameter' do
@@ -2301,7 +2389,7 @@ RSpec.describe 'Posts API', type: :request do
         end
 
         [:tag, :external_tag].each do |parameter|
-          it "includes external tag removal history through #{ parameter }" do
+          it "includes external removal history through the legacy API's #{ parameter }" do
             external_post.post_external_tags.destroy_all
             PostVersionRecorder.record!(
                 post: external_post.reload, event_type: :update, created_by_user: member)