Add endpoint for fetching diverging commit countsid-stale-branches

Extract diverging_commit_counts into a service class

5 files changed, 82 insertions, 50 deletions

diff --git a/app/controllers/projects/branches_controller.rb b/app/controllers/projects/branches_controller.rb
index fc708400657..da5efe4f21c 100644
--- a/app/controllers/projects/branches_controller.rb
+++ b/app/controllers/projects/branches_controller.rb
@@ -25,15 +25,6 @@ class Projects::BranchesController < Projects::ApplicationController
         @refs_pipelines = @project.ci_pipelines.latest_successful_for_refs(@branches.map(&:name))
         @merged_branch_names = repository.merged_branch_names(@branches.map(&:name))
 
-        # n+1: https://gitlab.com/gitlab-org/gitlab-ce/issues/48097
-        Gitlab::GitalyClient.allow_n_plus_1_calls do
-          @max_commits = @branches.reduce(0) do |memo, branch|
-            diverging_commit_counts = repository.diverging_commit_counts(branch)
-            [memo, diverging_commit_counts.values_at(:behind, :ahead, :distance)]
-              .flatten.compact.max
-          end
-        end
-
         # https://gitlab.com/gitlab-org/gitlab-ce/issues/48097
         Gitlab::GitalyClient.allow_n_plus_1_calls do
           render
@@ -51,6 +42,19 @@ class Projects::BranchesController < Projects::ApplicationController
     @branches = @repository.recent_branches
   end
 
+  def diverging_commit_counts
+    respond_to do |format|
+      format.json do
+        service = Branches::DivergingCommitCountsService.new(repository)
+        branches = BranchesFinder.new(repository, params.permit(names: [])).execute
+
+        Gitlab::GitalyClient.allow_n_plus_1_calls do
+          render json: branches.to_h { |branch| [branch.name, service.call(branch)] }
+        end
+      end
+    end
+  end
+
   # rubocop: disable CodeReuse/ActiveRecord
   def create
     branch_name = strip_tags(sanitize(params[:branch_name]))
diff --git a/app/finders/branches_finder.rb b/app/finders/branches_finder.rb
index 45d5591e81b..b462c8053fa 100644
--- a/app/finders/branches_finder.rb
+++ b/app/finders/branches_finder.rb
@@ -9,6 +9,7 @@ class BranchesFinder
   def execute
     branches = repository.branches_sorted_by(sort)
     branches = by_search(branches)
+    branches = by_names(branches)
     branches
   end
 
@@ -16,6 +17,10 @@ class BranchesFinder
 
   attr_reader :repository, :params
 
+  def names
+    @params[:names].presence
+  end
+
   def search
     @params[:search].presence
   end
@@ -59,4 +64,13 @@ class BranchesFinder
   def find_exact_match_index(matches, term)
     matches.index { |branch| branch.name.casecmp(term) == 0 }
   end
+
+  def by_names(branches)
+    return branches unless names
+
+    branch_names = names.to_set
+    branches.filter do |branch|
+      branch_names.include?(branch.name)
+    end
+  end
 end
diff --git a/app/models/repository.rb b/app/models/repository.rb
index e05d3dd58ac..992ed7485e5 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -282,46 +282,6 @@ class Repository
     ref_exists?(keep_around_ref_name(sha))
   end
 
-  def diverging_commit_counts(branch)
-    return diverging_commit_counts_without_max(branch) if Feature.enabled?('gitaly_count_diverging_commits_no_max')
-
-    ## TODO: deprecate the below code after 12.0
-    @root_ref_hash ||= raw_repository.commit(root_ref).id
-    cache.fetch(:"diverging_commit_counts_#{branch.name}") do
-      # Rugged seems to throw a `ReferenceError` when given branch_names rather
-      # than SHA-1 hashes
-      branch_sha = branch.dereferenced_target.sha
-
-      number_commits_behind, number_commits_ahead =
-        raw_repository.diverging_commit_count(
-          @root_ref_hash,
-          branch_sha,
-          max_count: MAX_DIVERGING_COUNT)
-
-      if number_commits_behind + number_commits_ahead >= MAX_DIVERGING_COUNT
-        { distance: MAX_DIVERGING_COUNT }
-      else
-        { behind: number_commits_behind, ahead: number_commits_ahead }
-      end
-    end
-  end
-
-  def diverging_commit_counts_without_max(branch)
-    @root_ref_hash ||= raw_repository.commit(root_ref).id
-    cache.fetch(:"diverging_commit_counts_without_max_#{branch.name}") do
-      # Rugged seems to throw a `ReferenceError` when given branch_names rather
-      # than SHA-1 hashes
-      branch_sha = branch.dereferenced_target.sha
-
-      number_commits_behind, number_commits_ahead =
-        raw_repository.diverging_commit_count(
-          @root_ref_hash,
-          branch_sha)
-
-      { behind: number_commits_behind, ahead: number_commits_ahead }
-    end
-  end
-
   def archive_metadata(ref, storage_path, format = "tar.gz", append_sha:, path: nil)
     raw_repository.archive_metadata(
       ref,
diff --git a/app/services/branches/diverging_commit_counts_service.rb b/app/services/branches/diverging_commit_counts_service.rb
new file mode 100644
index 00000000000..f947cec1663
--- /dev/null
+++ b/app/services/branches/diverging_commit_counts_service.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module Branches
+  class DivergingCommitCountsService
+    def initialize(repository)
+      @repository = repository
+      @cache = Gitlab::RepositoryCache.new(repository)
+    end
+
+    def call(branch)
+      if Feature.enabled?('gitaly_count_diverging_commits_no_max')
+        diverging_commit_counts_without_max(branch)
+      else
+        diverging_commit_counts(branch)
+      end
+    end
+
+    private
+
+    attr_reader :repository, :cache
+
+    delegate :raw_repository, to: :repository
+
+    def diverging_commit_counts(branch)
+      ## TODO: deprecate the below code after 12.0
+      @root_ref_hash ||= raw_repository.commit(repository.root_ref).id
+      cache.fetch(:"diverging_commit_counts_#{branch.name}") do
+        number_commits_behind, number_commits_ahead =
+          repository.raw_repository.diverging_commit_count(
+            @root_ref_hash,
+            branch.dereferenced_target.sha,
+            max_count: Repository::MAX_DIVERGING_COUNT)
+
+        if number_commits_behind + number_commits_ahead >= Repository::MAX_DIVERGING_COUNT
+          { distance: Repository::MAX_DIVERGING_COUNT }
+        else
+          { behind: number_commits_behind, ahead: number_commits_ahead }
+        end
+      end
+    end
+
+    def diverging_commit_counts_without_max(branch)
+      @root_ref_hash ||= raw_repository.commit(repository.root_ref).id
+      cache.fetch(:"diverging_commit_counts_without_max_#{branch.name}") do
+        number_commits_behind, number_commits_ahead =
+          raw_repository.diverging_commit_count(
+            @root_ref_hash,
+            branch.dereferenced_target.sha)
+
+        { behind: number_commits_behind, ahead: number_commits_ahead }
+      end
+    end
+  end
+end
diff --git a/app/views/projects/branches/_branch.html.haml b/app/views/projects/branches/_branch.html.haml
index 3638334d61c..f97b259f8f2 100644
--- a/app/views/projects/branches/_branch.html.haml
+++ b/app/views/projects/branches/_branch.html.haml
@@ -1,6 +1,6 @@
 - merged = local_assigns.fetch(:merged, false)
 - commit = @repository.commit(branch.dereferenced_target)
-- diverging_commit_counts = @repository.diverging_commit_counts(branch)
+- diverging_commit_counts = Branches::DivergingCommitCountsService.new(@repository).call(branch)
 - number_commits_distance = diverging_commit_counts[:distance]
 - number_commits_behind = diverging_commit_counts[:behind]
 - number_commits_ahead = diverging_commit_counts[:ahead]