Merge branch 'smarter-cache-invalidation' into 'master'

Smarter cache invalidation

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/23550

See merge request !7360

7 files changed, 454 insertions, 284 deletions

diff --git a/spec/lib/gitlab/file_detector_spec.rb b/spec/lib/gitlab/file_detector_spec.rb
new file mode 100644
index 00000000000..e5ba13bbaf8
--- /dev/null
+++ b/spec/lib/gitlab/file_detector_spec.rb
@@ -0,0 +1,59 @@
+require 'spec_helper'
+
+describe Gitlab::FileDetector do
+  describe '.types_in_paths' do
+    it 'returns the file types for the given paths' do
+      expect(described_class.types_in_paths(%w(README.md CHANGELOG VERSION VERSION))).
+        to eq(%i{readme changelog version})
+    end
+
+    it 'does not include unrecognized file paths' do
+      expect(described_class.types_in_paths(%w(README.md foo.txt))).
+        to eq(%i{readme})
+    end
+  end
+
+  describe '.type_of' do
+    it 'returns the type of a README file' do
+      expect(described_class.type_of('README.md')).to eq(:readme)
+    end
+
+    it 'returns the type of a changelog file' do
+      %w(CHANGELOG HISTORY CHANGES NEWS).each do |file|
+        expect(described_class.type_of(file)).to eq(:changelog)
+      end
+    end
+
+    it 'returns the type of a license file' do
+      %w(LICENSE LICENCE COPYING).each do |file|
+        expect(described_class.type_of(file)).to eq(:license)
+      end
+    end
+
+    it 'returns the type of a version file' do
+      expect(described_class.type_of('VERSION')).to eq(:version)
+    end
+
+    it 'returns the type of a .gitignore file' do
+      expect(described_class.type_of('.gitignore')).to eq(:gitignore)
+    end
+
+    it 'returns the type of a Koding config file' do
+      expect(described_class.type_of('.koding.yml')).to eq(:koding)
+    end
+
+    it 'returns the type of a GitLab CI config file' do
+      expect(described_class.type_of('.gitlab-ci.yml')).to eq(:gitlab_ci)
+    end
+
+    it 'returns the type of an avatar' do
+      %w(logo.gif logo.png logo.jpg).each do |file|
+        expect(described_class.type_of(file)).to eq(:avatar)
+      end
+    end
+
+    it 'returns nil for an unknown file' do
+      expect(described_class.type_of('foo.txt')).to be_nil
+    end
+  end
+end
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 25458e20618..e183fa88873 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -1572,7 +1572,7 @@ describe Project, models: true do
     end
 
     it 'expires the avatar cache' do
-      expect(project.repository).to receive(:expire_avatar_cache).with(project.default_branch)
+      expect(project.repository).to receive(:expire_avatar_cache)
       project.change_head(project.default_branch)
     end
 
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index 72ac41f3472..04afb8ebc98 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -464,11 +464,7 @@ describe Repository, models: true do
     end
   end
 
-  describe "#changelog" do
-    before do
-      repository.send(:cache).expire(:changelog)
-    end
-
+  describe "#changelog", caching: true do
     it 'accepts changelog' do
       expect(repository.tree).to receive(:blobs).and_return([TestBlob.new('changelog')])
 
@@ -500,17 +496,16 @@ describe Repository, models: true do
     end
   end
 
-  describe "#license_blob" do
+  describe "#license_blob", caching: true do
     before do
-      repository.send(:cache).expire(:license_blob)
       repository.remove_file(user, 'LICENSE', 'Remove LICENSE', 'master')
     end
 
     it 'handles when HEAD points to non-existent ref' do
       repository.commit_file(user, 'LICENSE', 'Copyright!', 'Add LICENSE', 'master', false)
-      rugged = double('rugged')
-      expect(rugged).to receive(:head_unborn?).and_return(true)
-      expect(repository).to receive(:rugged).and_return(rugged)
+
+      allow(repository).to receive(:file_on_head).
+        and_raise(Rugged::ReferenceError)
 
       expect(repository.license_blob).to be_nil
     end
@@ -537,22 +532,18 @@ describe Repository, models: true do
     end
   end
 
-  describe '#license_key' do
+  describe '#license_key', caching: true do
     before do
-      repository.send(:cache).expire(:license_key)
       repository.remove_file(user, 'LICENSE', 'Remove LICENSE', 'master')
     end
 
-    it 'handles when HEAD points to non-existent ref' do
-      repository.commit_file(user, 'LICENSE', 'Copyright!', 'Add LICENSE', 'master', false)
-      rugged = double('rugged')
-      expect(rugged).to receive(:head_unborn?).and_return(true)
-      expect(repository).to receive(:rugged).and_return(rugged)
-
+    it 'returns nil when no license is detected' do
       expect(repository.license_key).to be_nil
     end
 
-    it 'returns nil when no license is detected' do
+    it 'returns nil when the repository does not exist' do
+      expect(repository).to receive(:exists?).and_return(false)
+
       expect(repository.license_key).to be_nil
     end
 
@@ -569,7 +560,7 @@ describe Repository, models: true do
     end
   end
 
-  describe "#gitlab_ci_yml" do
+  describe "#gitlab_ci_yml", caching: true do
     it 'returns valid file' do
       files = [TestBlob.new('file'), TestBlob.new('.gitlab-ci.yml'), TestBlob.new('copying')]
       expect(repository.tree).to receive(:blobs).and_return(files)
@@ -583,7 +574,7 @@ describe Repository, models: true do
     end
 
     it 'returns nil for empty repository' do
-      expect(repository).to receive(:empty?).and_return(true)
+      allow(repository).to receive(:file_on_head).and_raise(Rugged::ReferenceError)
       expect(repository.gitlab_ci_yml).to be_nil
     end
   end
@@ -778,7 +769,6 @@ describe Repository, models: true do
         expect(repository).not_to receive(:expire_emptiness_caches)
         expect(repository).to     receive(:expire_branches_cache)
         expect(repository).to     receive(:expire_has_visible_content_cache)
-        expect(repository).to     receive(:expire_branch_count_cache)
 
         repository.update_branch_with_hooks(user, 'new-feature') { new_rev }
       end
@@ -797,7 +787,6 @@ describe Repository, models: true do
         expect(empty_repository).to receive(:expire_emptiness_caches)
         expect(empty_repository).to receive(:expire_branches_cache)
         expect(empty_repository).to receive(:expire_has_visible_content_cache)
-        expect(empty_repository).to receive(:expire_branch_count_cache)
 
         empty_repository.commit_file(user, 'CHANGELOG', 'Changelog!',
                                      'Updates file content', 'master', false)
@@ -811,8 +800,7 @@ describe Repository, models: true do
     end
 
     it 'returns false when a repository does not exist' do
-      expect(repository.raw_repository).to receive(:rugged).
-        and_raise(Gitlab::Git::Repository::NoRepository)
+      allow(repository).to receive(:refs_directory_exists?).and_return(false)
 
       expect(repository.exists?).to eq(false)
     end
@@ -916,34 +904,6 @@ describe Repository, models: true do
     end
   end
 
-  describe '#expire_cache' do
-    it 'expires all caches' do
-      expect(repository).to receive(:expire_branch_cache)
-
-      repository.expire_cache
-    end
-
-    it 'expires the caches for a specific branch' do
-      expect(repository).to receive(:expire_branch_cache).with('master')
-
-      repository.expire_cache('master')
-    end
-
-    it 'expires the emptiness caches for an empty repository' do
-      expect(repository).to receive(:empty?).and_return(true)
-      expect(repository).to receive(:expire_emptiness_caches)
-
-      repository.expire_cache
-    end
-
-    it 'does not expire the emptiness caches for a non-empty repository' do
-      expect(repository).to receive(:empty?).and_return(false)
-      expect(repository).not_to receive(:expire_emptiness_caches)
-
-      repository.expire_cache
-    end
-  end
-
   describe '#expire_root_ref_cache' do
     it 'expires the root reference cache' do
       repository.root_ref
@@ -1003,12 +963,23 @@ describe Repository, models: true do
   describe '#expire_emptiness_caches' do
     let(:cache) { repository.send(:cache) }
 
-    it 'expires the caches' do
+    it 'expires the caches for an empty repository' do
+      allow(repository).to receive(:empty?).and_return(true)
+
       expect(cache).to receive(:expire).with(:empty?)
       expect(repository).to receive(:expire_has_visible_content_cache)
 
       repository.expire_emptiness_caches
     end
+
+    it 'does not expire the cache for a non-empty repository' do
+      allow(repository).to receive(:empty?).and_return(false)
+
+      expect(cache).not_to receive(:expire).with(:empty?)
+      expect(repository).not_to receive(:expire_has_visible_content_cache)
+
+      repository.expire_emptiness_caches
+    end
   end
 
   describe :skip_merged_commit do
@@ -1120,24 +1091,12 @@ describe Repository, models: true do
         repository.before_delete
       end
 
-      it 'flushes the tag count cache' do
-        expect(repository).to receive(:expire_tag_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the branches cache' do
         expect(repository).to receive(:expire_branches_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the branch count cache' do
-        expect(repository).to receive(:expire_branch_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the root ref cache' do
         expect(repository).to receive(:expire_root_ref_cache)
 
@@ -1162,36 +1121,18 @@ describe Repository, models: true do
         allow(repository).to receive(:exists?).and_return(true)
       end
 
-      it 'flushes the caches that depend on repository data' do
-        expect(repository).to receive(:expire_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the tags cache' do
         expect(repository).to receive(:expire_tags_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the tag count cache' do
-        expect(repository).to receive(:expire_tag_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the branches cache' do
         expect(repository).to receive(:expire_branches_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the branch count cache' do
-        expect(repository).to receive(:expire_branch_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the root ref cache' do
         expect(repository).to receive(:expire_root_ref_cache)
 
@@ -1222,8 +1163,9 @@ describe Repository, models: true do
 
   describe '#before_push_tag' do
     it 'flushes the cache' do
-      expect(repository).to receive(:expire_cache)
-      expect(repository).to receive(:expire_tag_count_cache)
+      expect(repository).to receive(:expire_statistics_caches)
+      expect(repository).to receive(:expire_emptiness_caches)
+      expect(repository).to receive(:expire_tags_cache)
 
       repository.before_push_tag
     end
@@ -1240,17 +1182,23 @@ describe Repository, models: true do
   describe '#after_import' do
     it 'flushes and builds the cache' do
       expect(repository).to receive(:expire_content_cache)
-      expect(repository).to receive(:build_cache)
+      expect(repository).to receive(:expire_tags_cache)
+      expect(repository).to receive(:expire_branches_cache)
 
       repository.after_import
     end
   end
 
   describe '#after_push_commit' do
-    it 'flushes the cache' do
-      expect(repository).to receive(:expire_cache).with('master', '123')
+    it 'expires statistics caches' do
+      expect(repository).to receive(:expire_statistics_caches).
+        and_call_original
 
-      repository.after_push_commit('master', '123')
+      expect(repository).to receive(:expire_branch_cache).
+        with('master').
+        and_call_original
+
+      repository.after_push_commit('master')
     end
   end
 
@@ -1302,7 +1250,8 @@ describe Repository, models: true do
 
   describe '#before_remove_tag' do
     it 'flushes the tag cache' do
-      expect(repository).to receive(:expire_tag_count_cache)
+      expect(repository).to receive(:expire_tags_cache).and_call_original
+      expect(repository).to receive(:expire_statistics_caches).and_call_original
 
       repository.before_remove_tag
     end
@@ -1320,23 +1269,23 @@ describe Repository, models: true do
     end
   end
 
-  describe '#expire_branch_count_cache' do
-    let(:cache) { repository.send(:cache) }
-
+  describe '#expire_branches_cache' do
     it 'expires the cache' do
-      expect(cache).to receive(:expire).with(:branch_count)
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(branch_names branch_count)).
+        and_call_original
 
-      repository.expire_branch_count_cache
+      repository.expire_branches_cache
     end
   end
 
-  describe '#expire_tag_count_cache' do
-    let(:cache) { repository.send(:cache) }
-
+  describe '#expire_tags_cache' do
     it 'expires the cache' do
-      expect(cache).to receive(:expire).with(:tag_count)
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(tag_names tag_count)).
+        and_call_original
 
-      repository.expire_tag_count_cache
+      repository.expire_tags_cache
     end
   end
 
@@ -1412,170 +1361,316 @@ describe Repository, models: true do
 
   describe '#avatar' do
     it 'returns nil if repo does not exist' do
-      expect(repository).to receive(:exists?).and_return(false)
+      expect(repository).to receive(:file_on_head).
+        and_raise(Rugged::ReferenceError)
 
       expect(repository.avatar).to eq(nil)
     end
 
     it 'returns the first avatar file found in the repository' do
-      expect(repository).to receive(:blob_at_branch).
-        with('master', 'logo.png').
-        and_return(true)
+      expect(repository).to receive(:file_on_head).
+        with(:avatar).
+        and_return(double(:tree, path: 'logo.png'))
 
       expect(repository.avatar).to eq('logo.png')
     end
 
     it 'caches the output' do
-      allow(repository).to receive(:blob_at_branch).
-        with('master', 'logo.png').
-        and_return(true)
-
-      expect(repository.avatar).to eq('logo.png')
+      expect(repository).to receive(:file_on_head).
+        with(:avatar).
+        once.
+        and_return(double(:tree, path: 'logo.png'))
 
-      expect(repository).not_to receive(:blob_at_branch)
-      expect(repository.avatar).to eq('logo.png')
+      2.times { expect(repository.avatar).to eq('logo.png') }
     end
   end
 
-  describe '#expire_avatar_cache' do
+  describe '#expire_exists_cache' do
     let(:cache) { repository.send(:cache) }
 
-    before do
-      allow(repository).to receive(:cache).and_return(cache)
+    it 'expires the cache' do
+      expect(cache).to receive(:expire).with(:exists?)
+
+      repository.expire_exists_cache
     end
+  end
 
-    context 'without a branch or revision' do
-      it 'flushes the cache' do
-        expect(cache).to receive(:expire).with(:avatar)
+  describe "#keep_around" do
+    it "does not fail if we attempt to reference bad commit" do
+      expect(repository.kept_around?('abc1234')).to be_falsey
+    end
 
-        repository.expire_avatar_cache
-      end
+    it "stores a reference to the specified commit sha so it isn't garbage collected" do
+      repository.keep_around(sample_commit.id)
+
+      expect(repository.kept_around?(sample_commit.id)).to be_truthy
+    end
+
+    it "attempting to call keep_around on truncated ref does not fail" do
+      repository.keep_around(sample_commit.id)
+      ref = repository.send(:keep_around_ref_name, sample_commit.id)
+      path = File.join(repository.path, ref)
+      # Corrupt the reference
+      File.truncate(path, 0)
+
+      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+
+      repository.keep_around(sample_commit.id)
+
+      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+
+      File.delete(path)
+    end
+  end
+
+  describe '#update_ref!' do
+    it 'can create a ref' do
+      repository.update_ref!('refs/heads/foobar', 'refs/heads/master', Gitlab::Git::BLANK_SHA)
+
+      expect(repository.find_branch('foobar')).not_to be_nil
     end
 
-    context 'with a branch' do
-      it 'does not flush the cache if the branch is not the default branch' do
-        expect(cache).not_to receive(:expire)
+    it 'raises CommitError when the ref update fails' do
+      expect do
+        repository.update_ref!('refs/heads/master', 'refs/heads/master', Gitlab::Git::BLANK_SHA)
+      end.to raise_error(Repository::CommitError)
+    end
+  end
+
+  describe '#contribution_guide', caching: true do
+    it 'returns and caches the output' do
+      expect(repository).to receive(:file_on_head).
+        with(:contributing).
+        and_return(Gitlab::Git::Tree.new(path: 'CONTRIBUTING.md')).
+        once
 
-        repository.expire_avatar_cache('cats')
+      2.times do
+        expect(repository.contribution_guide).
+          to be_an_instance_of(Gitlab::Git::Tree)
       end
+    end
+  end
 
-      it 'flushes the cache if the branch equals the default branch' do
-        expect(cache).to receive(:expire).with(:avatar)
+  describe '#gitignore', caching: true do
+    it 'returns and caches the output' do
+      expect(repository).to receive(:file_on_head).
+        with(:gitignore).
+        and_return(Gitlab::Git::Tree.new(path: '.gitignore')).
+        once
 
-        repository.expire_avatar_cache(repository.root_ref)
+      2.times do
+        expect(repository.gitignore).to be_an_instance_of(Gitlab::Git::Tree)
       end
     end
+  end
 
-    context 'with a branch and revision' do
-      let(:commit) { double(:commit) }
+  describe '#koding_yml', caching: true do
+    it 'returns and caches the output' do
+      expect(repository).to receive(:file_on_head).
+        with(:koding).
+        and_return(Gitlab::Git::Tree.new(path: '.koding.yml')).
+        once
 
-      before do
-        allow(repository).to receive(:commit).and_return(commit)
+      2.times do
+        expect(repository.koding_yml).to be_an_instance_of(Gitlab::Git::Tree)
       end
+    end
+  end
 
-      it 'does not flush the cache if the commit does not change any logos' do
-        diff = double(:diff, new_path: 'test.txt')
+  describe '#readme', caching: true do
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:tree).with(:head).and_return(nil)
 
-        expect(commit).to receive(:raw_diffs).and_return([diff])
-        expect(cache).not_to receive(:expire)
+        expect(repository.readme).to be_nil
+      end
+    end
 
-        repository.expire_avatar_cache(repository.root_ref, '123')
+    context 'with an existing repository' do
+      it 'returns the README' do
+        expect(repository.readme).to be_an_instance_of(Gitlab::Git::Blob)
       end
+    end
+  end
 
-      it 'flushes the cache if the commit changes any of the logos' do
-        diff = double(:diff, new_path: Repository::AVATAR_FILES[0])
+  describe '#expire_statistics_caches' do
+    it 'expires the caches' do
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(size commit_count))
+
+      repository.expire_statistics_caches
+    end
+  end
 
-        expect(commit).to receive(:raw_diffs).and_return([diff])
-        expect(cache).to receive(:expire).with(:avatar)
+  describe '#expire_method_caches' do
+    it 'expires the caches of the given methods' do
+      expect_any_instance_of(RepositoryCache).to receive(:expire).with(:readme)
+      expect_any_instance_of(RepositoryCache).to receive(:expire).with(:gitignore)
 
-        repository.expire_avatar_cache(repository.root_ref, '123')
-      end
+      repository.expire_method_caches(%i(readme gitignore))
     end
   end
 
-  describe '#expire_exists_cache' do
-    let(:cache) { repository.send(:cache) }
+  describe '#expire_all_method_caches' do
+    it 'expires the caches of all methods' do
+      expect(repository).to receive(:expire_method_caches).
+        with(Repository::CACHED_METHODS)
+
+      repository.expire_all_method_caches
+    end
+  end
 
+  describe '#expire_avatar_cache' do
     it 'expires the cache' do
-      expect(cache).to receive(:expire).with(:exists?)
+      expect(repository).to receive(:expire_method_caches).with(%i(avatar))
 
-      repository.expire_exists_cache
+      repository.expire_avatar_cache
     end
   end
 
-  describe '#build_cache' do
-    let(:cache) { repository.send(:cache) }
+  describe '#file_on_head' do
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:tree).with(:head).and_return(nil)
 
-    it 'builds the caches if they do not already exist' do
-      cache_keys = repository.cache_keys + repository.cache_keys_for_branches_and_tags
+        expect(repository.file_on_head(:readme)).to be_nil
+      end
+    end
 
-      expect(cache).to receive(:exist?).
-        exactly(cache_keys.length).
-        times.
-        and_return(false)
+    context 'with a repository that has no blobs' do
+      it 'returns nil' do
+        expect_any_instance_of(Tree).to receive(:blobs).and_return([])
+
+        expect(repository.file_on_head(:readme)).to be_nil
+      end
+    end
+
+    context 'with an existing repository' do
+      it 'returns a Gitlab::Git::Tree' do
+        expect(repository.file_on_head(:readme)).
+          to be_an_instance_of(Gitlab::Git::Tree)
+      end
+    end
+  end
+
+  describe '#head_tree' do
+    context 'with an existing repository' do
+      it 'returns a Tree' do
+        expect(repository.head_tree).to be_an_instance_of(Tree)
+      end
+    end
+
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:head_commit).and_return(nil)
+
+        expect(repository.head_tree).to be_nil
+      end
+    end
+  end
 
-      cache_keys.each do |key|
-        expect(repository).to receive(key)
+  describe '#tree' do
+    context 'using a non-existing repository' do
+      before do
+        allow(repository).to receive(:head_commit).and_return(nil)
+      end
+
+      it 'returns nil' do
+        expect(repository.tree(:head)).to be_nil
       end
 
-      repository.build_cache
+      it 'returns nil when using a path' do
+        expect(repository.tree(:head, 'README.md')).to be_nil
+      end
     end
 
-    it 'does not build any caches that already exist' do
-      cache_keys = repository.cache_keys + repository.cache_keys_for_branches_and_tags
+    context 'using an existing repository' do
+      it 'returns a Tree' do
+        expect(repository.tree(:head)).to be_an_instance_of(Tree)
+      end
+    end
+  end
 
-      expect(cache).to receive(:exist?).
-        exactly(cache_keys.length).
-        times.
-        and_return(true)
+  describe '#size' do
+    context 'with a non-existing repository' do
+      it 'returns 0' do
+        expect(repository).to receive(:exists?).and_return(false)
 
-      cache_keys.each do |key|
-        expect(repository).not_to receive(key)
+        expect(repository.size).to eq(0.0)
       end
+    end
 
-      repository.build_cache
+    context 'with an existing repository' do
+      it 'returns the repository size as a Float' do
+        expect(repository.size).to be_an_instance_of(Float)
+      end
     end
   end
 
-  describe "#keep_around" do
-    it "does not fail if we attempt to reference bad commit" do
-      expect(repository.kept_around?('abc1234')).to be_falsey
+  describe '#commit_count' do
+    context 'with a non-existing repository' do
+      it 'returns 0' do
+        expect(repository).to receive(:root_ref).and_return(nil)
+
+        expect(repository.commit_count).to eq(0)
+      end
     end
 
-    it "stores a reference to the specified commit sha so it isn't garbage collected" do
-      repository.keep_around(sample_commit.id)
+    context 'with an existing repository' do
+      it 'returns the commit count' do
+        expect(repository.commit_count).to be_an_instance_of(Fixnum)
+      end
+    end
+  end
 
-      expect(repository.kept_around?(sample_commit.id)).to be_truthy
+  describe '#cache_method_output', caching: true do
+    context 'with a non-existing repository' do
+      let(:value) do
+        repository.cache_method_output(:cats, fallback: 10) do
+          raise Rugged::ReferenceError
+        end
+      end
+
+      it 'returns a fallback value' do
+        expect(value).to eq(10)
+      end
+
+      it 'does not cache the data' do
+        value
+
+        expect(repository.instance_variable_defined?(:@cats)).to eq(false)
+        expect(repository.send(:cache).exist?(:cats)).to eq(false)
+      end
     end
 
-    it "attempting to call keep_around on truncated ref does not fail" do
-      repository.keep_around(sample_commit.id)
-      ref = repository.send(:keep_around_ref_name, sample_commit.id)
-      path = File.join(repository.path, ref)
-      # Corrupt the reference
-      File.truncate(path, 0)
+    context 'with an existing repository' do
+      it 'caches the output' do
+        object = double
 
-      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+        expect(object).to receive(:number).once.and_return(10)
 
-      repository.keep_around(sample_commit.id)
+        2.times do
+          val = repository.cache_method_output(:cats) { object.number }
 
-      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+          expect(val).to eq(10)
+        end
 
-      File.delete(path)
+        expect(repository.send(:cache).exist?(:cats)).to eq(true)
+        expect(repository.instance_variable_get(:@cats)).to eq(10)
+      end
     end
   end
 
-  describe '#update_ref!' do
-    it 'can create a ref' do
-      repository.update_ref!('refs/heads/foobar', 'refs/heads/master', Gitlab::Git::BLANK_SHA)
+  describe '#refresh_method_caches' do
+    it 'refreshes the caches of the given types' do
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(readme license_blob license_key))
 
-      expect(repository.find_branch('foobar')).not_to be_nil
-    end
+      expect(repository).to receive(:readme)
+      expect(repository).to receive(:license_blob)
+      expect(repository).to receive(:license_key)
 
-    it 'raises CommitError when the ref update fails' do
-      expect do
-        repository.update_ref!('refs/heads/master', 'refs/heads/master', Gitlab::Git::BLANK_SHA)
-      end.to raise_error(Repository::CommitError)
+      repository.refresh_method_caches(%i(readme license))
     end
   end
 end
diff --git a/spec/requests/api/branches_spec.rb b/spec/requests/api/branches_spec.rb
index 8f605757186..fe6b875b997 100644
--- a/spec/requests/api/branches_spec.rb
+++ b/spec/requests/api/branches_spec.rb
@@ -14,7 +14,7 @@ describe API::API, api: true  do
 
   describe "GET /projects/:id/repository/branches" do
     it "returns an array of project branches" do
-      project.repository.expire_cache
+      project.repository.expire_all_method_caches
 
       get api("/projects/#{project.id}/repository/branches", user)
       expect(response).to have_http_status(200)
diff --git a/spec/services/git_push_service_spec.rb b/spec/services/git_push_service_spec.rb
index 62f9982e840..9d7702f5c96 100644
--- a/spec/services/git_push_service_spec.rb
+++ b/spec/services/git_push_service_spec.rb
@@ -27,27 +27,14 @@ describe GitPushService, services: true do
 
       it { is_expected.to be_truthy }
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
 
-      it 'flushes the visible content cache' do
-        expect(project.repository).to receive(:expire_has_visible_content_cache)
-
-        subject
-      end
-
-      it 'flushes the branches cache' do
-        expect(project.repository).to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'flushes the branch count cache' do
-        expect(project.repository).to receive(:expire_branch_count_cache)
+      it 'calls the after_create_branch hook' do
+        expect(project.repository).to receive(:after_create_branch)
 
         subject
       end
@@ -56,21 +43,8 @@ describe GitPushService, services: true do
     context 'existing branch' do
       it { is_expected.to be_truthy }
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
-
-        subject
-      end
-
-      it 'does not flush the branches cache' do
-        expect(project.repository).not_to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'does not flush the branch count cache' do
-        expect(project.repository).not_to receive(:expire_branch_count_cache)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
@@ -81,27 +55,14 @@ describe GitPushService, services: true do
 
       it { is_expected.to be_truthy }
 
-      it 'flushes the visible content cache' do
-        expect(project.repository).to receive(:expire_has_visible_content_cache)
-
-        subject
-      end
-
-      it 'flushes the branches cache' do
-        expect(project.repository).to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'flushes the branch count cache' do
-        expect(project.repository).to receive(:expire_branch_count_cache)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
+      it 'calls the after_remove_branch hook' do
+        expect(project.repository).to receive(:after_remove_branch)
 
         subject
       end
@@ -598,6 +559,51 @@ describe GitPushService, services: true do
     end
   end
 
+  describe '#update_caches' do
+    let(:service) do
+      described_class.new(project,
+                          user,
+                          oldrev: sample_commit.parent_id,
+                          newrev: sample_commit.id,
+                          ref: 'refs/heads/master')
+    end
+
+    context 'on the default branch' do
+      before do
+        allow(service).to receive(:is_default_branch?).and_return(true)
+      end
+
+      it 'flushes the caches of any special files that have been changed' do
+        commit = double(:commit)
+        diff = double(:diff, new_path: 'README.md')
+
+        expect(commit).to receive(:raw_diffs).with(deltas_only: true).
+          and_return([diff])
+
+        service.push_commits = [commit]
+
+        expect(ProjectCacheWorker).to receive(:perform_async).
+          with(project.id, %i(readme))
+
+        service.update_caches
+      end
+    end
+
+    context 'on a non-default branch' do
+      before do
+        allow(service).to receive(:is_default_branch?).and_return(false)
+      end
+
+      it 'does not flush any conditional caches' do
+        expect(ProjectCacheWorker).to receive(:perform_async).
+          with(project.id, []).
+          and_call_original
+
+        service.update_caches
+      end
+    end
+  end
+
   def execute_service(project, user, oldrev, newrev, ref)
     service = described_class.new(project, user, oldrev: oldrev, newrev: newrev, ref: ref )
     service.execute
diff --git a/spec/services/git_tag_push_service_spec.rb b/spec/services/git_tag_push_service_spec.rb
index 0879e3ab4c8..bd074b9bd71 100644
--- a/spec/services/git_tag_push_service_spec.rb
+++ b/spec/services/git_tag_push_service_spec.rb
@@ -18,7 +18,7 @@ describe GitTagPushService, services: true do
     end
 
     it 'flushes general cached data' do
-      expect(project.repository).to receive(:expire_cache)
+      expect(project.repository).to receive(:before_push_tag)
 
       subject
     end
@@ -28,12 +28,6 @@ describe GitTagPushService, services: true do
 
       subject
     end
-
-    it 'flushes the tag count cache' do
-      expect(project.repository).to receive(:expire_tag_count_cache)
-
-      subject
-    end
   end
 
   describe "Git Tag Push Data" do
diff --git a/spec/workers/project_cache_worker_spec.rb b/spec/workers/project_cache_worker_spec.rb
index bfa8c0ff2c6..855c28b584e 100644
--- a/spec/workers/project_cache_worker_spec.rb
+++ b/spec/workers/project_cache_worker_spec.rb
@@ -2,62 +2,78 @@ require 'spec_helper'
 
 describe ProjectCacheWorker do
   let(:project) { create(:project) }
+  let(:worker) { described_class.new }
 
-  subject { described_class.new }
-
-  describe '.perform_async' do
-    it 'schedules the job when no lease exists' do
-      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:exists?).
-        and_return(false)
+  describe '#perform' do
+    before do
+      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:try_obtain).
+        and_return(true)
+    end
 
-      expect_any_instance_of(described_class).to receive(:perform)
+    context 'with a non-existing project' do
+      it 'does nothing' do
+        expect(worker).not_to receive(:update_repository_size)
 
-      described_class.perform_async(project.id)
+        worker.perform(-1)
+      end
     end
 
-    it 'does not schedule the job when a lease exists' do
-      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:exists?).
-        and_return(true)
+    context 'with an existing project without a repository' do
+      it 'does nothing' do
+        allow_any_instance_of(Repository).to receive(:exists?).and_return(false)
 
-      expect_any_instance_of(described_class).not_to receive(:perform)
+        expect(worker).not_to receive(:update_repository_size)
 
-      described_class.perform_async(project.id)
+        worker.perform(project.id)
+      end
     end
-  end
 
-  describe '#perform' do
-    context 'when an exclusive lease can be obtained' do
-      before do
-        allow(subject).to receive(:try_obtain_lease_for).with(project.id).
-          and_return(true)
-      end
+    context 'with an existing project' do
+      it 'updates the repository size' do
+        expect(worker).to receive(:update_repository_size).and_call_original
 
-      it 'updates project cache data' do
-        expect_any_instance_of(Repository).to receive(:size)
-        expect_any_instance_of(Repository).to receive(:commit_count)
+        worker.perform(project.id)
+      end
 
-        expect_any_instance_of(Project).to receive(:update_repository_size)
-        expect_any_instance_of(Project).to receive(:update_commit_count)
+      it 'updates the commit count' do
+        expect_any_instance_of(Project).to receive(:update_commit_count).
+          and_call_original
 
-        subject.perform(project.id)
+        worker.perform(project.id)
       end
 
-      it 'handles missing repository data' do
-        expect_any_instance_of(Repository).to receive(:exists?).and_return(false)
-        expect_any_instance_of(Repository).not_to receive(:size)
+      it 'refreshes the method caches' do
+        expect_any_instance_of(Repository).to receive(:refresh_method_caches).
+          with(%i(readme)).
+          and_call_original
 
-        subject.perform(project.id)
+        worker.perform(project.id, %i(readme))
       end
     end
+  end
 
-    context 'when an exclusive lease can not be obtained' do
-      it 'does nothing' do
-        allow(subject).to receive(:try_obtain_lease_for).with(project.id).
+  describe '#update_repository_size' do
+    context 'when a lease could not be obtained' do
+      it 'does not update the repository size' do
+        allow(worker).to receive(:try_obtain_lease_for).
+          with(project.id, :update_repository_size).
           and_return(false)
 
-        expect(subject).not_to receive(:update_caches)
+        expect(project).not_to receive(:update_repository_size)
+
+        worker.update_repository_size(project)
+      end
+    end
+
+    context 'when a lease could be obtained' do
+      it 'updates the repository size' do
+        allow(worker).to receive(:try_obtain_lease_for).
+          with(project.id, :update_repository_size).
+          and_return(true)
+
+        expect(project).to receive(:update_repository_size).and_call_original
 
-        subject.perform(project.id)
+        worker.update_repository_size(project)
       end
     end
   end