Merge branch '23062-allow-git-log-to-accept-follow-and-skip' into 'master'

Make Git history follow renames again by performing the --skip in Ruby

Closes #23062

See merge request !9314

4 files changed, 123 insertions, 51 deletions

diff --git a/app/models/repository.rb b/app/models/repository.rb
index 1762118278a..0dbf246c3a4 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -109,9 +109,7 @@ class Repository
       offset: offset,
       after: after,
       before: before,
-      # --follow doesn't play well with --skip. See:
-      # https://gitlab.com/gitlab-org/gitlab-ce/issues/3574#note_3040520
-      follow: false,
+      follow: path.present?,
       skip_merges: skip_merges
     }
 
diff --git a/changelogs/unreleased/23062-allow-git-log-to-accept-follow-and-skip.yml b/changelogs/unreleased/23062-allow-git-log-to-accept-follow-and-skip.yml
new file mode 100644
index 00000000000..f7c856040e0
--- /dev/null
+++ b/changelogs/unreleased/23062-allow-git-log-to-accept-follow-and-skip.yml
@@ -0,0 +1,4 @@
+---
+title: Make Git history follow renames again by performing the --skip in Ruby
+merge_request:
+author:
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index b8354d7bf04..8ec90885231 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -324,24 +324,30 @@ module Gitlab
       end
 
       def log_by_shell(sha, options)
-        cmd = %W(#{Gitlab.config.git.bin_path} --git-dir=#{path} log)
-        cmd += %W(-n #{options[:limit].to_i})
-        cmd += %w(--format=%H)
-        cmd += %W(--skip=#{options[:offset].to_i})
-        cmd += %w(--follow) if options[:follow]
-        cmd += %w(--no-merges) if options[:skip_merges]
-        cmd += %W(--after=#{options[:after].iso8601}) if options[:after]
-        cmd += %W(--before=#{options[:before].iso8601}) if options[:before]
-        cmd += [sha]
-        cmd += %W(-- #{options[:path]}) if options[:path].present?
-
-        raw_output = IO.popen(cmd) {|io| io.read }
-
-        log = raw_output.lines.map do |c|
-          Rugged::Commit.new(rugged, c.strip)
-        end
-
-        log.is_a?(Array) ? log : []
+        limit = options[:limit].to_i
+        offset = options[:offset].to_i
+        use_follow_flag = options[:follow] && options[:path].present?
+
+        # We will perform the offset in Ruby because --follow doesn't play well with --skip.
+        # See: https://gitlab.com/gitlab-org/gitlab-ce/issues/3574#note_3040520
+        offset_in_ruby = use_follow_flag && options[:offset].present?
+        limit += offset if offset_in_ruby
+
+        cmd = %W[#{Gitlab.config.git.bin_path} --git-dir=#{path} log]
+        cmd << "--max-count=#{limit}"
+        cmd << '--format=%H'
+        cmd << "--skip=#{offset}" unless offset_in_ruby
+        cmd << '--follow' if use_follow_flag
+        cmd << '--no-merges' if options[:skip_merges]
+        cmd << "--after=#{options[:after].iso8601}" if options[:after]
+        cmd << "--before=#{options[:before].iso8601}" if options[:before]
+        cmd << sha
+        cmd += %W[-- #{options[:path]}] if options[:path].present?
+
+        raw_output = IO.popen(cmd) { |io| io.read }
+        lines = offset_in_ruby ? raw_output.lines.drop(offset) : raw_output.lines
+
+        lines.map! { |c| Rugged::Commit.new(rugged, c.strip) }
       end
 
       def sha_from_ref(ref)
diff --git a/spec/lib/gitlab/git/repository_spec.rb b/spec/lib/gitlab/git/repository_spec.rb
index 766f16bb824..1919542ca25 100644
--- a/spec/lib/gitlab/git/repository_spec.rb
+++ b/spec/lib/gitlab/git/repository_spec.rb
@@ -529,7 +529,7 @@ describe Gitlab::Git::Repository, seed_helper: true do
     commit_with_new_name = nil
     rename_commit = nil
 
-    before(:all) do
+    before(:context) do
       # Add new commits so that there's a renamed file in the commit history
       repo = Gitlab::Git::Repository.new(TEST_REPO_PATH).rugged
 
@@ -538,49 +538,119 @@ describe Gitlab::Git::Repository, seed_helper: true do
       commit_with_new_name = new_commit_edit_new_file(repo)
     end
 
+    after(:context) do
+      # Erase our commits so other tests get the original repo
+      repo = Gitlab::Git::Repository.new(TEST_REPO_PATH).rugged
+      repo.references.update("refs/heads/master", SeedRepo::LastCommit::ID)
+    end
+
     context "where 'follow' == true" do
-      options = { ref: "master", follow: true }
+      let(:options) { { ref: "master", follow: true } }
 
       context "and 'path' is a directory" do
-        let(:log_commits) do
-          repository.log(options.merge(path: "encoding"))
-        end
+        it "does not follow renames" do
+          log_commits = repository.log(options.merge(path: "encoding"))
 
-        it "should not follow renames" do
-          expect(log_commits).to include(commit_with_new_name)
-          expect(log_commits).to include(rename_commit)
-          expect(log_commits).not_to include(commit_with_old_name)
+          aggregate_failures do
+            expect(log_commits).to include(commit_with_new_name)
+            expect(log_commits).to include(rename_commit)
+            expect(log_commits).not_to include(commit_with_old_name)
+          end
         end
       end
 
       context "and 'path' is a file that matches the new filename" do
-        let(:log_commits) do
-          repository.log(options.merge(path: "encoding/CHANGELOG"))
+        context 'without offset' do
+          it "follows renames" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG"))
+
+            aggregate_failures do
+              expect(log_commits).to include(commit_with_new_name)
+              expect(log_commits).to include(rename_commit)
+              expect(log_commits).to include(commit_with_old_name)
+            end
+          end
         end
 
-        it "should follow renames" do
-          expect(log_commits).to include(commit_with_new_name)
-          expect(log_commits).to include(rename_commit)
-          expect(log_commits).to include(commit_with_old_name)
+        context 'with offset=1' do
+          it "follows renames and skip the latest commit" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 1))
+
+            aggregate_failures do
+              expect(log_commits).not_to include(commit_with_new_name)
+              expect(log_commits).to include(rename_commit)
+              expect(log_commits).to include(commit_with_old_name)
+            end
+          end
+        end
+
+        context 'with offset=1', 'and limit=1' do
+          it "follows renames, skip the latest commit and return only one commit" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 1, limit: 1))
+
+            expect(log_commits).to contain_exactly(rename_commit)
+          end
+        end
+
+        context 'with offset=1', 'and limit=2' do
+          it "follows renames, skip the latest commit and return only two commits" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 1, limit: 2))
+
+            aggregate_failures do
+              expect(log_commits).to contain_exactly(rename_commit, commit_with_old_name)
+            end
+          end
+        end
+
+        context 'with offset=2' do
+          it "follows renames and skip the latest commit" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 2))
+
+            aggregate_failures do
+              expect(log_commits).not_to include(commit_with_new_name)
+              expect(log_commits).not_to include(rename_commit)
+              expect(log_commits).to include(commit_with_old_name)
+            end
+          end
+        end
+
+        context 'with offset=2', 'and limit=1' do
+          it "follows renames, skip the two latest commit and return only one commit" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 2, limit: 1))
+
+            expect(log_commits).to contain_exactly(commit_with_old_name)
+          end
+        end
+
+        context 'with offset=2', 'and limit=2' do
+          it "follows renames, skip the two latest commit and return only one commit" do
+            log_commits = repository.log(options.merge(path: "encoding/CHANGELOG", offset: 2, limit: 2))
+
+            aggregate_failures do
+              expect(log_commits).not_to include(commit_with_new_name)
+              expect(log_commits).not_to include(rename_commit)
+              expect(log_commits).to include(commit_with_old_name)
+            end
+          end
         end
       end
 
       context "and 'path' is a file that matches the old filename" do
-        let(:log_commits) do
-          repository.log(options.merge(path: "CHANGELOG"))
-        end
+        it "does not follow renames" do
+          log_commits = repository.log(options.merge(path: "CHANGELOG"))
 
-        it "should not follow renames" do
-          expect(log_commits).to include(commit_with_old_name)
-          expect(log_commits).to include(rename_commit)
-          expect(log_commits).not_to include(commit_with_new_name)
+          aggregate_failures do
+            expect(log_commits).not_to include(commit_with_new_name)
+            expect(log_commits).to include(rename_commit)
+            expect(log_commits).to include(commit_with_old_name)
+          end
         end
       end
 
       context "unknown ref" do
-        let(:log_commits) { repository.log(options.merge(ref: 'unknown')) }
+        it "returns an empty array" do
+          log_commits = repository.log(options.merge(ref: 'unknown'))
 
-        it "should return empty" do
           expect(log_commits).to eq([])
         end
       end
@@ -699,12 +769,6 @@ describe Gitlab::Git::Repository, seed_helper: true do
         end
       end
     end
-
-    after(:all) do
-      # Erase our commits so other tests get the original repo
-      repo = Gitlab::Git::Repository.new(TEST_REPO_PATH).rugged
-      repo.references.update("refs/heads/master", SeedRepo::LastCommit::ID)
-    end
   end
 
   describe "#commits_between" do