Don't treat anonymous users as owners when group has pending invites

The `members` table can have entries where `user_id: nil`, because people can
invite group members by email. We never want to include those as members,
because it might cause confusion with the anonymous (logged out) user.

6 files changed, 37 insertions, 6 deletions

diff --git a/app/models/group.rb b/app/models/group.rb
index dfa4e8adedd..bd5735ed82e 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -167,10 +167,14 @@ class Group < Namespace
   end
 
   def has_owner?(user)
+    return false unless user
+
     members_with_parents.owners.where(user_id: user).any?
   end
 
   def has_master?(user)
+    return false unless user
+
     members_with_parents.masters.where(user_id: user).any?
   end
 
@@ -212,7 +216,7 @@ class Group < Namespace
   end
 
   def members_with_parents
-    GroupMember.non_request.where(source_id: ancestors.pluck(:id).push(id))
+    GroupMember.active.where(source_id: ancestors.pluck(:id).push(id)).where.not(user_id: nil)
   end
 
   def users_with_parents
diff --git a/app/policies/project_policy.rb b/app/policies/project_policy.rb
index d27bbf2948c..0133091db57 100644
--- a/app/policies/project_policy.rb
+++ b/app/policies/project_policy.rb
@@ -10,7 +10,8 @@ class ProjectPolicy < BasePolicy
 
   desc "User is a project owner"
   condition :owner do
-    @user && project.owner == @user || (project.group && project.group.has_owner?(@user))
+    (project.owner.present? && project.owner == @user) ||
+      project.group&.has_owner?(@user)
   end
 
   desc "Project has public builds enabled"
diff --git a/changelogs/unreleased/35444-error-500-viewing-notes-with-anonymous-user.yml b/changelogs/unreleased/35444-error-500-viewing-notes-with-anonymous-user.yml
new file mode 100644
index 00000000000..9b8bc1d0d99
--- /dev/null
+++ b/changelogs/unreleased/35444-error-500-viewing-notes-with-anonymous-user.yml
@@ -0,0 +1,4 @@
+---
+title: Fix anonymous access to public projects in groups with pending invites
+merge_request:
+author:
diff --git a/spec/models/ability_spec.rb b/spec/models/ability_spec.rb
index dc7a0d80752..58f1a620ab4 100644
--- a/spec/models/ability_spec.rb
+++ b/spec/models/ability_spec.rb
@@ -98,7 +98,7 @@ describe Ability, lib: true do
         user2 = build(:user, external: true)
         users = [user1, user2]
 
-        expect(project).to receive(:owner).twice.and_return(user1)
+        expect(project).to receive(:owner).at_least(:once).and_return(user1)
 
         expect(described_class.users_that_can_read_project(users, project))
           .to eq([user1])
@@ -109,7 +109,7 @@ describe Ability, lib: true do
         user2 = build(:user, external: true)
         users = [user1, user2]
 
-        expect(project.team).to receive(:members).twice.and_return([user1])
+        expect(project.team).to receive(:members).at_least(:once).and_return([user1])
 
         expect(described_class.users_that_can_read_project(users, project))
           .to eq([user1])
@@ -140,7 +140,7 @@ describe Ability, lib: true do
         user2 = build(:user, external: true)
         users = [user1, user2]
 
-        expect(project).to receive(:owner).twice.and_return(user1)
+        expect(project).to receive(:owner).at_least(:once).and_return(user1)
 
         expect(described_class.users_that_can_read_project(users, project))
           .to eq([user1])
@@ -151,7 +151,7 @@ describe Ability, lib: true do
         user2 = build(:user, external: true)
         users = [user1, user2]
 
-        expect(project.team).to receive(:members).twice.and_return([user1])
+        expect(project.team).to receive(:members).at_least(:once).and_return([user1])
 
         expect(described_class.users_that_can_read_project(users, project))
           .to eq([user1])
diff --git a/spec/models/group_spec.rb b/spec/models/group_spec.rb
index 770176451fe..d8e868265ed 100644
--- a/spec/models/group_spec.rb
+++ b/spec/models/group_spec.rb
@@ -236,6 +236,7 @@ describe Group, models: true do
   describe '#has_owner?' do
     before do
       @members = setup_group_members(group)
+      create(:group_member, :invited, :owner, group: group)
     end
 
     it { expect(group.has_owner?(@members[:owner])).to be_truthy }
@@ -244,11 +245,13 @@ describe Group, models: true do
     it { expect(group.has_owner?(@members[:reporter])).to be_falsey }
     it { expect(group.has_owner?(@members[:guest])).to be_falsey }
     it { expect(group.has_owner?(@members[:requester])).to be_falsey }
+    it { expect(group.has_owner?(nil)).to be_falsey }
   end
 
   describe '#has_master?' do
     before do
       @members = setup_group_members(group)
+      create(:group_member, :invited, :master, group: group)
     end
 
     it { expect(group.has_master?(@members[:owner])).to be_falsey }
@@ -257,6 +260,7 @@ describe Group, models: true do
     it { expect(group.has_master?(@members[:reporter])).to be_falsey }
     it { expect(group.has_master?(@members[:guest])).to be_falsey }
     it { expect(group.has_master?(@members[:requester])).to be_falsey }
+    it { expect(group.has_master?(nil)).to be_falsey }
   end
 
   describe '#lfs_enabled?' do
diff --git a/spec/policies/project_policy_spec.rb b/spec/policies/project_policy_spec.rb
index 4ed788af811..f244975e597 100644
--- a/spec/policies/project_policy_spec.rb
+++ b/spec/policies/project_policy_spec.rb
@@ -127,6 +127,24 @@ describe ProjectPolicy, models: true do
     end
   end
 
+  context 'when a project has pending invites, and the current user is anonymous' do
+    let(:group) { create(:group, :public) }
+    let(:project) { create(:empty_project, :public, namespace: group) }
+    let(:user_permissions) { [:create_project, :create_issue, :create_note, :upload_file] }
+    let(:anonymous_permissions) { guest_permissions - user_permissions }
+
+    subject { described_class.new(nil, project) }
+
+    before do
+      create(:group_member, :invited, group: group)
+    end
+
+    it 'does not grant owner access' do
+      expect_allowed(*anonymous_permissions)
+      expect_disallowed(*user_permissions)
+    end
+  end
+
   context 'abilities for non-public projects' do
     let(:project) { create(:empty_project, namespace: owner.namespace) }