fix: optimise WIP pacts by using branch/tag heads

lib/pact_broker/pacts/pact_publication_dataset_module.rb

@@ -199,7 +199,10 @@ def old_latest_for_consumer_branch(branch_name)
       # The latest pact publication for each tag
       # This uses the old logic of "the latest pact for a version that has a tag" (which always returns a pact)
       # rather than "the pact for the latest version with a tag"
-      # Need to see about updating this.
+      #
+      # For 'pacts for verification' this has been replaced by for_all_tag_heads
+      # This should only be used for the UI
+      # @return [Sequel::Dataset<PactBroker::Pacts::PactPublication>]
       def latest_by_consumer_tag
         tags_join = {
           Sequel[:pact_publications][:consumer_version_id] => Sequel[:tags][:version_id],
@@ -228,6 +231,7 @@ def latest_by_consumer_tag
       # This uses the old logic of "the latest pact for a version that has a tag" (which always returns a pact)
       # rather than "the pact for the latest version with a tag"
       # Need to see about updating this.
+      # @return [Sequel::Dataset<PactBroker::Pacts::PactPublication>]
       def latest_for_consumer_tag(tag_name)
         tags_join = {
           Sequel[:pact_publications][:consumer_version_id] => Sequel[:tags][:version_id],
@@ -278,6 +282,30 @@ def for_latest_consumer_versions_with_tag(tag_name)
          .remove_overridden_revisions_from_complete_query
       end
 
+      # The pacts for the latest versions for each tag.
+      # Will not return a pact if the pact is no longer published for a particular tag
+      # NEW LOGIC
+      # @return [Sequel::Dataset<PactBroker::Pacts::PactPublication>]
+      def for_all_tag_heads
+        head_tags = PactBroker::Domain::Tag
+                      .select_group(:pacticipant_id, :name)
+                      .select_append{ max(version_order).as(:latest_version_order) }
+
+        head_tags_join = {
+          Sequel[:pact_publications][:consumer_id] => Sequel[:head_tags][:pacticipant_id],
+          Sequel[:pact_publications][:consumer_version_order] => Sequel[:head_tags][:latest_version_order]
+        }
+
+        base_query = self
+        if no_columns_selected?
+          base_query = base_query.select_all_qualified.select_append(Sequel[:head_tags][:name].as(:tag_name))
+        end
+
+        base_query
+          .join(head_tags, head_tags_join, { table_alias: :head_tags })
+         .remove_overridden_revisions_from_complete_query
+      end
+
       def in_environments
         currently_deployed_join = {
           Sequel[:pact_publications][:consumer_version_id] => Sequel[:currently_deployed_version_ids][:version_id]

lib/pact_broker/pacts/pacts_for_verification_repository.rb

@@ -64,15 +64,15 @@ def find_wip(provider_name, provider_version_branch, provider_tags_names, explic
           provider_tags_names,
           wip_start_date,
           explicitly_specified_verifiable_pacts,
-          :latest_by_consumer_tag
+          :for_all_tag_heads
         )
 
         wip_by_consumer_branches = find_wip_pact_versions_for_provider_by_provider_tags(
           provider,
           provider_tags_names,
           wip_start_date,
           explicitly_specified_verifiable_pacts,
-          :latest_by_consumer_branch
+          :for_all_branch_heads
         )
 
         deduplicate_verifiable_pacts(wip_by_consumer_tags + wip_by_consumer_branches).sort

spec/lib/pact_broker/pacts/pact_publication_dataset_module_spec.rb

@@ -244,6 +244,53 @@ module Pacts
         end
       end
 
+      describe "for_all_tag_heads" do
+        before do
+          td.create_consumer("Foo")
+            .create_provider("Bar")
+            .create_consumer_version("1", tag_names: ["main"])
+            .create_pact
+            .create_consumer_version("2", tag_names: ["feat/x"])
+            .create_pact
+            .create_consumer_version("3", tag_names: ["main"], comment: "latest")
+            .create_pact
+            .create_consumer_version("4", tag_names: ["feat/x"], comment: "latest")
+            .create_pact
+            .create_consumer("FooZ")
+            .create_consumer_version("6", tag_names: ["main"], comment: "Different consumer")
+            .create_pact
+            .create_consumer_version("7", comment: "No branch")
+            .create_pact
+            .create_consumer_version("8", tag_names: ["main"], comment: "No pact")
+        end
+
+        subject { PactPublication.for_all_tag_heads.all_allowing_lazy_load }
+
+        let(:foo) { PactBroker::Domain::Pacticipant.where(name: "Foo").single_record }
+        let(:bar) { PactBroker::Domain::Pacticipant.where(name: "Bar").single_record }
+        let(:foo_z) { PactBroker::Domain::Pacticipant.where(name: "FooZ").single_record }
+
+        it "returns the pacts belonging to the latest tagged version for each tag" do
+          expect(subject.size).to eq 2
+          subject.collect(&:values)
+
+          expect(subject.find { |pp| pp.consumer_id == foo.id && pp[:tag_name] == "main" }.consumer_version.number).to eq "3"
+          expect(subject.find { |pp| pp.consumer_id == foo.id && pp[:tag_name] == "feat/x" }.consumer_version.number).to eq "4"
+        end
+
+        it "does not return extra columns" do
+          expect(subject.first.values.keys.sort).to eq (PactPublication.columns + [:tag_name]).sort
+        end
+
+        context "when columns are already selected" do
+          subject { PactPublication.select(Sequel[:pact_publications][:id]).latest_by_consumer_tag }
+
+          it "does not override them" do
+            expect(subject.all.first.values.keys).to eq [:id]
+          end
+        end
+      end
+
       describe "overall_latest" do
         before do
           td.create_consumer("Foo")