Avoid returning bottom match when reaching bottom limit58035-expand-mr-diff

2 files changed, 36 insertions, 2 deletions

diff --git a/app/presenters/blobs/unfold_presenter.rb b/app/presenters/blobs/unfold_presenter.rb
index 5976f730314..4c6dd6895cf 100644
--- a/app/presenters/blobs/unfold_presenter.rb
+++ b/app/presenters/blobs/unfold_presenter.rb
@@ -81,6 +81,7 @@ module Blobs
 
     def add_match_line(diff_lines)
       return unless unfold?
+      return if bottom? && to >= all_lines_size
 
       if bottom? && to < all_lines_size
         old_pos = to - offset
diff --git a/spec/presenters/blobs/unfold_presenter_spec.rb b/spec/presenters/blobs/unfold_presenter_spec.rb
index 46be9fe87eb..ab3f8080257 100644
--- a/spec/presenters/blobs/unfold_presenter_spec.rb
+++ b/spec/presenters/blobs/unfold_presenter_spec.rb
@@ -98,8 +98,9 @@ describe Blobs::UnfoldPresenter do
       end
     end
 
-    context 'when since is greater than 1' do
-      let(:params) { { since: 5, to: 10, offset: 10 } }
+    context 'when "since" is greater than 1' do
+      let(:default_params) { { since: 5, to: 10, offset: 10 } }
+      let(:params) { default_params }
 
       it 'adds top match line' do
         line = subject.diff_lines.first
@@ -108,6 +109,38 @@ describe Blobs::UnfoldPresenter do
         expect(line.old_pos).to eq(5)
         expect(line.new_pos).to eq(5)
       end
+
+      context '"to" is higher than blob size' do
+        let(:params) { default_params.merge(to: total_lines + 10, bottom: true) }
+
+        it 'does not add bottom match line' do
+          line = subject.diff_lines.last
+
+          expect(line.type).to be_nil
+        end
+      end
+
+      context '"to" is equal to blob size' do
+        let(:params) { default_params.merge(to: total_lines, bottom: true) }
+
+        it 'does not add bottom match line' do
+          line = subject.diff_lines.last
+
+          expect(line.type).to be_nil
+        end
+      end
+
+      context '"to" is less than blob size' do
+        let(:params) { default_params.merge(to: total_lines - 3, bottom: true) }
+
+        it 'adds bottom match line' do
+          line = subject.diff_lines.last
+
+          expect(line.type).to eq('match')
+          expect(line.old_pos).to eq(total_lines - 3 - params[:offset])
+          expect(line.new_pos).to eq(total_lines - 3)
+        end
+      end
     end
 
     context 'when "to" is less than blob size' do