Preload authors on commits and blame pages

Currently the full potential of lazy_author
is not used
Let's try and use lazy_author&.itself instead
of lazy_author.__sync to load authors in batches

app/controllers/projects/commits_controller.rb

@@ -72,6 +72,8 @@ class Projects::CommitsController < Projects::ApplicationController
         @repository.commits(@ref, path: @path, limit: @limit, offset: @offset)
       end
 
+    @commits.each(&:lazy_author) # preload authors
+
     @commits = @commits.with_latest_pipeline(@ref)
     @commits = set_commits_for_rendering(@commits)
   end

app/helpers/avatars_helper.rb

@@ -56,16 +56,6 @@ module AvatarsHelper
     }))
   end
 
-  def user_avatar_url_for(only_path: true, **options)
-    if options[:url]
-      options[:url]
-    elsif options[:user]
-      avatar_icon_for_user(options[:user], options[:size], only_path: only_path)
-    else
-      avatar_icon_for_email(options[:user_email], options[:size], only_path: only_path)
-    end
-  end
-
   def user_avatar_without_link(options = {})
     avatar_size = options[:size] || 16
     user_name = options[:user].try(:name) || options[:user_name]
@@ -111,6 +101,19 @@ module AvatarsHelper
 
   private
 
+  def user_avatar_url_for(only_path: true, **options)
+    return options[:url] if options[:url]
+
+    email = options[:user_email]
+    user = options.key?(:user) ? options[:user] : User.find_by_any_email(email)
+
+    if user
+      avatar_icon_for_user(user, options[:size], only_path: only_path)
+    else
+      gravatar_icon(email, options[:size])
+    end
+  end
+
   def source_icon(source, options = {})
     avatar_url = source.try(:avatar_url)
 

app/models/commit.rb

@@ -257,10 +257,9 @@ class Commit
   end
 
   def author
-    # We use __sync so that we get the actual objects back (including an actual
-    # nil), instead of a wrapper, as returning a wrapped nil breaks a lot of
-    # code.
-    lazy_author.__sync
+    strong_memoize(:author) do
+      lazy_author&.itself
+    end
   end
   request_cache(:author) { author_email.downcase }
 

changelogs/unreleased/id-blame-controller-performance.yml

+---
+title: Optimize SQL requests for BlameController and CommitsController
+merge_request: 18342
+author:
+type: performance

lib/gitlab/blame.rb

@@ -17,6 +17,7 @@ module Gitlab
       i = 0
       blame.each do |commit, line|
         commit = Commit.new(commit, project)
+        commit.lazy_author # preload author
 
         sha = commit.sha
         if prev_sha != sha