Reduce queries in IssueReferenceFilterbanzai-issue-filter-queries

This reduces the number of queries executed in IssueReferenceFilter by
retrieving the various projects/issues that may be referenced in batches
_before_ iterating over all the HTML nodes.

A chunk of the logic resides in AbstractReferenceFilter so it can be
re-used by other filters in the future.

2 files changed, 58 insertions, 3 deletions

diff --git a/spec/lib/banzai/filter/abstract_link_filter_spec.rb b/spec/lib/banzai/filter/abstract_link_filter_spec.rb
new file mode 100644
index 00000000000..0c55d8e19da
--- /dev/null
+++ b/spec/lib/banzai/filter/abstract_link_filter_spec.rb
@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe Banzai::Filter::AbstractReferenceFilter do
+  let(:project) { create(:empty_project) }
+
+  describe '#references_per_project' do
+    it 'returns a Hash containing references grouped per project paths' do
+      doc = Nokogiri::HTML.fragment("#1 #{project.to_reference}#2")
+      filter = described_class.new(doc, project: project)
+
+      expect(filter).to receive(:object_class).twice.and_return(Issue)
+      expect(filter).to receive(:object_sym).twice.and_return(:issue)
+
+      refs = filter.references_per_project
+
+      expect(refs).to be_an_instance_of(Hash)
+      expect(refs[project.to_reference]).to eq(Set.new(%w[1 2]))
+    end
+  end
+
+  describe '#projects_per_reference' do
+    it 'returns a Hash containing projects grouped per project paths' do
+      doc = Nokogiri::HTML.fragment('')
+      filter = described_class.new(doc, project: project)
+
+      expect(filter).to receive(:references_per_project).
+        and_return({ project.path_with_namespace => Set.new(%w[1]) })
+
+      expect(filter.projects_per_reference).
+        to eq({ project.path_with_namespace => project })
+    end
+  end
+
+  describe '#find_projects_for_paths' do
+    it 'returns a list of Projects for a list of paths' do
+      doc = Nokogiri::HTML.fragment('')
+      filter = described_class.new(doc, project: project)
+
+      expect(filter.find_projects_for_paths([project.path_with_namespace])).
+        to eq([project])
+    end
+  end
+
+  describe '#current_project_path' do
+    it 'returns the path of the current project' do
+      doc = Nokogiri::HTML.fragment('')
+      filter = described_class.new(doc, project: project)
+
+      expect(filter.current_project_path).to eq(project.path_with_namespace)
+    end
+  end
+end
diff --git a/spec/lib/banzai/filter/issue_reference_filter_spec.rb b/spec/lib/banzai/filter/issue_reference_filter_spec.rb
index 8e6a264970d..25f0bc2092f 100644
--- a/spec/lib/banzai/filter/issue_reference_filter_spec.rb
+++ b/spec/lib/banzai/filter/issue_reference_filter_spec.rb
@@ -25,7 +25,9 @@ describe Banzai::Filter::IssueReferenceFilter, lib: true do
     let(:reference) { issue.to_reference }
 
     it 'ignores valid references when using non-default tracker' do
-      expect(project).to receive(:get_issue).with(issue.iid).and_return(nil)
+      expect_any_instance_of(described_class).to receive(:find_object).
+        with(project, issue.iid).
+        and_return(nil)
 
       exp = act = "Issue #{reference}"
       expect(reference_filter(act).to_html).to eq exp
@@ -107,8 +109,9 @@ describe Banzai::Filter::IssueReferenceFilter, lib: true do
     let(:reference) { issue.to_reference(project) }
 
     it 'ignores valid references when cross-reference project uses external tracker' do
-      expect_any_instance_of(Project).to receive(:get_issue).
-        with(issue.iid).and_return(nil)
+      expect_any_instance_of(described_class).to receive(:find_object).
+        with(project2, issue.iid).
+        and_return(nil)
 
       exp = act = "Issue #{reference}"
       expect(reference_filter(act).to_html).to eq exp