Avoid mixing builds from different pipelines:

So we no longer join anything, just find the latest pipeline
and load builds from there to avoid mixing builds.

Thanks Kamil for the help and tests.

app/models/ci/build.rb

@@ -15,9 +15,6 @@ module Ci
     scope :with_artifacts, ->() { where.not(artifacts_file: nil) }
     scope :with_expired_artifacts, ->() { with_artifacts.where('artifacts_expire_at < ?', Time.now) }
     scope :last_month, ->() { where('created_at > ?', Date.today - 1.month) }
-    scope :latest_successful_with_artifacts, ->() do
-      with_artifacts.success.order(id: :desc)
-    end
     scope :manual_actions, ->() { where(when: :manual) }
 
     mount_uploader :artifacts_file, ArtifactUploader

app/models/ci/pipeline.rb

@@ -22,7 +22,7 @@ module Ci
 
     # ref can't be HEAD or SHA, can only be branch/tag name
     scope :latest_successful_for, ->(ref = default_branch) do
-      where(ref: ref).success.order(id: :desc)
+      where(ref: ref).success.order(id: :desc).limit(1)
     end
 
     def self.truncate_sha(sha)

app/models/project.rb

@@ -431,8 +431,13 @@ class Project < ActiveRecord::Base
 
   # ref can't be HEAD, can only be branch/tag name or SHA
   def latest_successful_builds_for(ref = default_branch)
-    builds.joins(:pipeline).merge(pipelines.latest_successful_for(ref)).
-      latest_successful_with_artifacts
+    latest_successful_pipeline = pipelines.latest_successful_for(ref).first
+
+    if latest_successful_pipeline
+      latest_successful_pipeline.builds.with_artifacts.latest
+    else
+      builds.none
+    end
   end
 
   def merge_base_commit(first_commit_id, second_commit_id)

spec/models/project_spec.rb

@@ -1148,6 +1148,36 @@ describe Project, models: true do
         end
       end
 
+      context 'with many builds' do
+        before do
+          @pipeline1 = create_pipeline
+          @pipeline2 = create_pipeline
+          @build1_p2 = create_build(@pipeline2, 'test')
+          @build1_p1 = create_build(@pipeline1, 'test')
+          @build2_p1 = create_build(@pipeline1, 'test2')
+          @build2_p2 = create_build(@pipeline2, 'test2')
+        end
+
+        it 'gives the latest build from latest pipeline' do
+          latest_builds = project.latest_successful_builds_for
+
+          expect(latest_builds).to contain_exactly(@build2_p2, @build1_p2)
+        end
+
+        def create_pipeline
+          create(:ci_pipeline, project: project,
+                 sha: project.commit.sha,
+                 ref: project.default_branch,
+                 status: 'success')
+        end
+
+        def create_build(pipe, name = 'test')
+          create(:ci_build, :success, :artifacts,
+                 pipeline: pipe,
+                 name: name)
+        end
+      end
+
       context 'with multiple pipelines and builds' do
         shared_examples 'latest successful one' do
           it 'gives the latest build from latest pipeline' do
@@ -1157,27 +1187,6 @@ describe Project, models: true do
           end
         end
 
-        context 'with all succeeded pipeline' do
-          before do
-            old_pipelines = Array.new(3).map do
-              create(:ci_pipeline, project: project,
-                                   sha: project.commit.sha,
-                                   ref: project.default_branch,
-                                   status: 'success')
-            end
-
-            # should not give this old build for the latest pipeline
-            create(:ci_build, :success, :artifacts, pipeline: pipeline)
-            build
-
-            old_pipelines.reverse_each do |pipe|
-              create(:ci_build, :success, :artifacts, pipeline: pipe)
-            end
-          end
-
-          it_behaves_like 'latest successful one'
-        end
-
         context 'with some pending pipeline' do
           before do
             # make sure pipeline was old, but still the latest success one