3 files changed, 22 insertions, 2 deletions
diff --git a/CHANGELOG b/CHANGELOG
index 9ffbf64fe1d..68fe893e645 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.14.0 (unreleased)
+  - Fix Error 500 when browsing projects with no HEAD (Stan Hu)
   - Fix full screen mode for snippet comments (Daniel Gerhardt)
   - Fix 404 error in files view after deleting the last file in a repository (Stan Hu)
   - Fix label read access for unauthenticated users (Daniel Gerhardt)
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index 3cd52b381bd..a675a292432 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -278,7 +278,8 @@ module ProjectsHelper
   end
 
   def readme_cache_key
-    [@project.id, @project.commit.sha, "readme"].join('-')
+    sha = @project.commit.try(:sha) || 'nil'
+    [@project.id, sha, "readme"].join('-')
   end
 
   def round_commit_count(project)
diff --git a/spec/helpers/projects_helper_spec.rb b/spec/helpers/projects_helper_spec.rb
index beb9b4e438e..99abb95d906 100644
--- a/spec/helpers/projects_helper_spec.rb
+++ b/spec/helpers/projects_helper_spec.rb
@@ -22,7 +22,7 @@ describe ProjectsHelper do
 
     let(:user) { create(:user) }
 
-    it "returns false if there are no approipriate permissions" do
+    it "returns false if there are no appropriate permissions" do
       allow(helper).to receive(:can?) { false }
 
       expect(helper.can_change_visibility_level?(project, user)).to be_falsey
@@ -52,4 +52,22 @@ describe ProjectsHelper do
       end
     end
   end
+
+  describe "readme_cache_key" do
+    let(:project) { create(:project) }
+
+    before do
+      helper.instance_variable_set(:@project, project)
+    end
+
+    it "returns a valid cach key" do
+      expect(helper.send(:readme_cache_key)).to eq("#{project.id}-#{project.commit.id}-readme")
+    end
+
+    it "returns a valid cache key if HEAD does not exist" do
+      allow(project).to receive(:commit) { nil }
+
+      expect(helper.send(:readme_cache_key)).to eq("#{project.id}-nil-readme")
+    end
+  end
 end