Fix N+1 for notification recipients on private projects

If we don't call #to_a, we're relying on the members already being loaded from
elsewhere. Otherwise we'll do a separate query for each user:

    [1] pry(main)> Project.first.team.members.include?(User.first)
      Project Load (0.7ms)  SELECT  "projects".* FROM "projects"  ORDER BY "projects"."id" ASC LIMIT 1
      ↳ (pry):3
      User Load (1.8ms)  SELECT  "users".* FROM "users"  ORDER BY "users"."id" ASC LIMIT 1
      ↳ (pry):3
      User Exists (0.6ms)  SELECT  1 AS one FROM "users" INNER JOIN "project_authorizations" ON "users"."id" = "project_authorizations"."user_id" WHERE "project_authorizations"."project_id" = $1 AND "users"."id" = $2 LIMIT 1  [["project_id", 1], ["id", 1]]
      ↳ (pry):3
    => true
    [2] pry(main)> Project.first.team.members.to_a.include?(User.first)
      Project Load (12.8ms)  SELECT  "projects".* FROM "projects"  ORDER BY "projects"."id" ASC LIMIT 1
      ↳ (pry):1
      User Load (9.6ms)  SELECT "users".* FROM "users" INNER JOIN "project_authorizations" ON "users"."id" = "project_authorizations"."user_id" WHERE "project_authorizations"."project_id" = $1  [["project_id", 1]]
      ↳ (pry):1
      User Load (0.6ms)  SELECT  "users".* FROM "users"  ORDER BY "users"."id" ASC LIMIT 1
      ↳ (pry):1
    => true

1 files changed, 5 insertions, 1 deletions

diff --git a/app/policies/project_policy.rb b/app/policies/project_policy.rb
index d0e84b1aa38..f2c246cd969 100644
--- a/app/policies/project_policy.rb
+++ b/app/policies/project_policy.rb
@@ -390,7 +390,11 @@ class ProjectPolicy < BasePolicy
     greedy_load_subject ||= !@user.persisted?
 
     if greedy_load_subject
-      project.team.members.include?(user)
+      # We want to load all the members with one query. Calling #include? on
+      # project.team.members will perform a separate query for each user, unless
+      # project.team.members was loaded before somewhere else. Calling #to_a
+      # ensures it's always loaded before checking for membership.
+      project.team.members.to_a.include?(user)
     else
       # otherwise we just make a specific query for
       # this particular user.