From 5a7be1bf3c86756ee17d6f776785d37f51170583 Mon Sep 17 00:00:00 2001
From: Joseph Snyder <joe.snyder@kitware.com>
Date: Thu, 18 Aug 2022 09:43:52 -0400
Subject: [PATCH 1/5] Introduce backend updates for toggle of diff preview

Add a column to both the project and the namespace settings which will
control whether a comment on a line in a merge request will show
the code section that goes with the comment.

Add necessary parts of "back end" code to utilize this column.
Front end will follow after this merge.

Changelog: added
---
 app/controllers/groups_controller.rb          |  1 +
 app/models/namespace.rb                       |  3 +-
 app/models/namespace_setting.rb               |  7 +++
 app/models/project.rb                         |  3 ++
 app/models/project_setting.rb                 | 13 ++++++
 app/policies/group_policy.rb                  |  1 +
 app/policies/project_policy.rb                |  1 +
 ..._preview_in_email_to_namespace_settings.rb |  9 ++++
 ...ff_preview_in_email_to_project_settings.rb |  9 ++++
 db/schema_migrations/20220603125200           |  1 +
 db/schema_migrations/20220817122907           |  1 +
 db/structure.sql                              |  2 +
 lib/api/helpers/projects_helpers.rb           |  2 +
 spec/models/namespace_setting_spec.rb         | 43 +++++++++++++++++++
 spec/models/project_setting_spec.rb           | 36 ++++++++++++++++
 spec/requests/api/project_attributes.yml      |  2 +
 16 files changed, 133 insertions(+), 1 deletion(-)
 create mode 100644 db/migrate/20220603125200_add_show_diff_preview_in_email_to_namespace_settings.rb
 create mode 100644 db/migrate/20220817122907_re_add_show_diff_preview_in_email_to_project_settings.rb
 create mode 100644 db/schema_migrations/20220603125200
 create mode 100644 db/schema_migrations/20220817122907

diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index 32b187c32606c9..aefbb43f3df46d 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -276,6 +276,7 @@ def group_params_attributes
       :avatar,
       :description,
       :emails_disabled,
+      :show_diff_preview_in_email,
       :mentions_disabled,
       :lfs_enabled,
       :name,
diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index c678dbfa6311ff..e8cd477c9b8631 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -128,7 +128,8 @@ class Namespace < ApplicationRecord
   delegate :avatar_url, to: :owner, allow_nil: true
   delegate :prevent_sharing_groups_outside_hierarchy, :prevent_sharing_groups_outside_hierarchy=,
            to: :namespace_settings, allow_nil: true
-
+  delegate :show_diff_preview_in_email, :show_diff_preview_in_email?, :show_diff_preview_in_email=,
+           to: :namespace_settings
   after_save :schedule_sync_event_worker, if: -> { saved_change_to_id? || saved_change_to_parent_id? }
   after_save :reload_namespace_details
 
diff --git a/app/models/namespace_setting.rb b/app/models/namespace_setting.rb
index fa9b525d4fe99a..ef75db485ba2a4 100644
--- a/app/models/namespace_setting.rb
+++ b/app/models/namespace_setting.rb
@@ -58,6 +58,13 @@ def prevent_sharing_groups_outside_hierarchy
     namespace.root_ancestor.prevent_sharing_groups_outside_hierarchy
   end
 
+  # any ancestor can hide diff content in emails
+  def show_diff_preview_in_email?
+    return namespace.parent.show_diff_preview_in_email? && namespace.show_diff_preview_in_email if namespace.has_parent?
+
+    show_diff_preview_in_email
+  end
+
   private
 
   def normalize_default_branch_name
diff --git a/app/models/project.rb b/app/models/project.rb
index 3053055bd771eb..d8d08cbffcccc7 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -462,6 +462,9 @@ def self.integration_association_name(name)
            :warn_about_potentially_unwanted_characters, :warn_about_potentially_unwanted_characters=,
            to: :project_setting, allow_nil: true
 
+  delegate :show_diff_preview_in_email, :show_diff_preview_in_email=, :show_diff_preview_in_email?,
+           to: :project_setting
+
   delegate :squash_always?, :squash_never?, :squash_enabled_by_default?, :squash_readonly?, to: :project_setting
   delegate :squash_option, :squash_option=, to: :project_setting
   delegate :mr_default_target_self, :mr_default_target_self=, to: :project_setting
diff --git a/app/models/project_setting.rb b/app/models/project_setting.rb
index 59d2e3deb4f033..a216de32ab8f61 100644
--- a/app/models/project_setting.rb
+++ b/app/models/project_setting.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class ProjectSetting < ApplicationRecord
+  include ::Gitlab::Utils::StrongMemoize
+
   ALLOWED_TARGET_PLATFORMS = %w(ios osx tvos watchos android).freeze
 
   belongs_to :project, inverse_of: :project_setting
@@ -47,6 +49,17 @@ def human_squash_option
     end
   end
 
+  def show_diff_preview_in_email?
+    strong_memoize(:show_diff_preview_in_email) do
+      # disabling in the namespace overrides the project setting
+      if project.group
+        super && project.group&.show_diff_preview_in_email?
+      else
+        !!super
+      end
+    end
+  end
+
   private
 
   def validates_mr_default_target_self
diff --git a/app/policies/group_policy.rb b/app/policies/group_policy.rb
index a264ff48c08e16..bee32d789aca45 100644
--- a/app/policies/group_policy.rb
+++ b/app/policies/group_policy.rb
@@ -193,6 +193,7 @@ class GroupPolicy < Namespaces::GroupProjectNamespaceSharedPolicy
     enable :set_note_created_at
     enable :set_emails_disabled
     enable :change_prevent_sharing_groups_outside_hierarchy
+    enable :set_show_diff_preview_in_email
     enable :change_new_user_signups_cap
     enable :update_default_branch_protection
     enable :create_deploy_token
diff --git a/app/policies/project_policy.rb b/app/policies/project_policy.rb
index f4f7275a78a35e..ccdad8e6be1716 100644
--- a/app/policies/project_policy.rb
+++ b/app/policies/project_policy.rb
@@ -267,6 +267,7 @@ class ProjectPolicy < BasePolicy
     enable :set_note_created_at
     enable :set_emails_disabled
     enable :set_show_default_award_emojis
+    enable :set_show_diff_preview_in_email
     enable :set_warn_about_potentially_unwanted_characters
 
     enable :register_project_runners
diff --git a/db/migrate/20220603125200_add_show_diff_preview_in_email_to_namespace_settings.rb b/db/migrate/20220603125200_add_show_diff_preview_in_email_to_namespace_settings.rb
new file mode 100644
index 00000000000000..ad32d58984075f
--- /dev/null
+++ b/db/migrate/20220603125200_add_show_diff_preview_in_email_to_namespace_settings.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AddShowDiffPreviewInEmailToNamespaceSettings < Gitlab::Database::Migration[2.0]
+  enable_lock_retries!
+
+  def change
+    add_column :namespace_settings, :show_diff_preview_in_email, :boolean, default: true, null: false
+  end
+end
diff --git a/db/migrate/20220817122907_re_add_show_diff_preview_in_email_to_project_settings.rb b/db/migrate/20220817122907_re_add_show_diff_preview_in_email_to_project_settings.rb
new file mode 100644
index 00000000000000..bb5649e3a99774
--- /dev/null
+++ b/db/migrate/20220817122907_re_add_show_diff_preview_in_email_to_project_settings.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class ReAddShowDiffPreviewInEmailToProjectSettings < Gitlab::Database::Migration[2.0]
+  enable_lock_retries!
+
+  def change
+    add_column :project_settings, :show_diff_preview_in_email, :boolean, default: true, null: false
+  end
+end
diff --git a/db/schema_migrations/20220603125200 b/db/schema_migrations/20220603125200
new file mode 100644
index 00000000000000..5da1d1992ab70e
--- /dev/null
+++ b/db/schema_migrations/20220603125200
@@ -0,0 +1 @@
+7631f2c1f9b2647ae6de47675305a2d5c1b213229c85b6f161412f83884bad87
\ No newline at end of file
diff --git a/db/schema_migrations/20220817122907 b/db/schema_migrations/20220817122907
new file mode 100644
index 00000000000000..fb6951e19d54e2
--- /dev/null
+++ b/db/schema_migrations/20220817122907
@@ -0,0 +1 @@
+4db4f50d2e23527516eccdeae60059803df7add21ca7a2c40f1670dba9744496
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index 9a2b98050460dc..8aea782ba4b718 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -17825,6 +17825,7 @@ CREATE TABLE namespace_settings (
     include_for_free_user_cap_preview boolean DEFAULT false NOT NULL,
     unique_project_download_limit_allowlist text[] DEFAULT '{}'::text[] NOT NULL,
     auto_ban_user_on_excessive_projects_download boolean DEFAULT false NOT NULL,
+    show_diff_preview_in_email boolean DEFAULT true NOT NULL,
     CONSTRAINT check_0ba93c78c7 CHECK ((char_length(default_branch_name) <= 255)),
     CONSTRAINT namespace_settings_unique_project_download_limit_allowlist_size CHECK ((cardinality(unique_project_download_limit_allowlist) <= 100))
 );
@@ -19936,6 +19937,7 @@ CREATE TABLE project_settings (
     target_platforms character varying[] DEFAULT '{}'::character varying[] NOT NULL,
     enforce_auth_checks_on_uploads boolean DEFAULT true NOT NULL,
     selective_code_owner_removals boolean DEFAULT false NOT NULL,
+    show_diff_preview_in_email boolean DEFAULT true NOT NULL,
     CONSTRAINT check_3a03e7557a CHECK ((char_length(previous_default_branch) <= 4096)),
     CONSTRAINT check_b09644994b CHECK ((char_length(squash_commit_template) <= 500)),
     CONSTRAINT check_bde223416c CHECK ((show_default_award_emojis IS NOT NULL)),
diff --git a/lib/api/helpers/projects_helpers.rb b/lib/api/helpers/projects_helpers.rb
index 40da4a4f8e82b9..7ca3f55b5a2c7e 100644
--- a/lib/api/helpers/projects_helpers.rb
+++ b/lib/api/helpers/projects_helpers.rb
@@ -39,6 +39,7 @@ module ProjectsHelpers
 
         optional :emails_disabled, type: Boolean, desc: 'Disable email notifications'
         optional :show_default_award_emojis, type: Boolean, desc: 'Show default award emojis'
+        optional :show_diff_preview_in_email, type: Boolean, desc: 'Include the code diff preview in merge request notification emails'
         optional :warn_about_potentially_unwanted_characters, type: Boolean, desc: 'Warn about Potentially Unwanted Characters'
         optional :enforce_auth_checks_on_uploads, type: Boolean, desc: 'Enforce auth check on uploads'
         optional :shared_runners_enabled, type: Boolean, desc: 'Flag indication if shared runners are enabled for that project'
@@ -159,6 +160,7 @@ def self.update_params_at_least_one_of
           :request_access_enabled,
           :resolve_outdated_diff_discussions,
           :restrict_user_defined_variables,
+          :show_diff_preview_in_email,
           :security_and_compliance_access_level,
           :squash_option,
           :shared_runners_enabled,
diff --git a/spec/models/namespace_setting_spec.rb b/spec/models/namespace_setting_spec.rb
index 25234db5734e0c..8b795405285560 100644
--- a/spec/models/namespace_setting_spec.rb
+++ b/spec/models/namespace_setting_spec.rb
@@ -127,4 +127,47 @@
       end
     end
   end
+
+  describe '#show_diff_preview_in_email?' do
+    context 'when not a subgroup' do
+      it 'returns false' do
+        settings = create(:namespace_settings, show_diff_preview_in_email: false)
+        group = create(:group, namespace_settings: settings )
+
+        expect(group.show_diff_preview_in_email?).to be_falsey
+      end
+
+      it 'returns true' do
+        settings = create(:namespace_settings, show_diff_preview_in_email: true)
+        group = create(:group, namespace_settings: settings )
+
+        expect(group.show_diff_preview_in_email?).to be_truthy
+      end
+
+      it 'does not query the db when there is no parent group' do
+        group = create(:group)
+
+        expect { group.show_diff_preview_in_email? }.not_to exceed_query_limit(0)
+      end
+    end
+
+    context 'when an ancestor has disabled diff previews' do
+      let(:settings) { create(:namespace_settings, show_diff_preview_in_email: false) }
+      let(:grandparent) { create(:group, namespace_settings: settings) }
+      let(:parent)      { create(:group, parent: grandparent) }
+      let!(:group) { create(:group, parent: parent) }
+
+      it 'returns false' do
+        expect(group.show_diff_preview_in_email?).to be_falsey
+      end
+
+      context 'when all ancestors have enabled diff previews' do
+        it 'returns true' do
+          grandparent.update_attribute(:show_diff_preview_in_email, true)
+
+          expect(group.show_diff_preview_in_email?).to be_truthy
+        end
+      end
+    end
+  end
 end
diff --git a/spec/models/project_setting_spec.rb b/spec/models/project_setting_spec.rb
index fb1601a5f9c1c7..e2569bc3fb4e58 100644
--- a/spec/models/project_setting_spec.rb
+++ b/spec/models/project_setting_spec.rb
@@ -63,4 +63,40 @@ def valid_target_platform_combinations
       target_platforms.permutation(n).to_a
     end
   end
+
+  describe '#show_diff_preview_in_email?' do
+    context 'when not a subgroup' do
+      it 'returns false' do
+        settings = create(:project_setting, show_diff_preview_in_email: false)
+        project = create(:project, project_setting: settings)
+        expect(project).not_to be_show_diff_preview_in_email
+      end
+
+      it 'returns true' do
+        settings = create(:project_setting, show_diff_preview_in_email: true)
+        project = create(:project, project_setting: settings)
+
+        expect(project).to be_show_diff_preview_in_email
+      end
+    end
+
+    context 'when a parent group has disabled diff previews' do
+      let(:namespace_settings) { create(:namespace_settings, show_diff_preview_in_email: false) }
+      let(:project_settings) { create(:project_setting, show_diff_preview_in_email: true) }
+      let(:group) { create(:group, namespace_settings: namespace_settings) }
+      let!(:project) { create(:project, namespace_id: group.id, project_setting: project_settings) }
+
+      it 'returns false' do
+        expect(project).not_to be_show_diff_preview_in_email
+      end
+
+      context 'when all ancestors have enabled diff previews' do
+        it 'returns true' do
+          group.update_attribute(:show_diff_preview_in_email, true)
+
+          expect(project).to be_show_diff_preview_in_email
+        end
+      end
+    end
+  end
 end
diff --git a/spec/requests/api/project_attributes.yml b/spec/requests/api/project_attributes.yml
index 670035187cb96a..1335fa02aaf49f 100644
--- a/spec/requests/api/project_attributes.yml
+++ b/spec/requests/api/project_attributes.yml
@@ -154,11 +154,13 @@ project_setting:
     - project_id
     - push_rule_id
     - show_default_award_emojis
+    - show_diff_preview_in_email
     - updated_at
     - cve_id_request_enabled
     - mr_default_target_self
     - target_platforms
     - selective_code_owner_removals
+    - show_diff_preview_in_email
 
 build_service_desk_setting: # service_desk_setting
   unexposed_attributes:
-- 
GitLab


From b3e0b0005a225d2e30bcc0419213def48e04d2a9 Mon Sep 17 00:00:00 2001
From: Kerri Miller <kerrizor@kerrizor.com>
Date: Thu, 25 Aug 2022 15:09:51 +0000
Subject: [PATCH 2/5] Apply suggested fix to properly fix spacing in
 namespace.rb

---
 app/models/namespace.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index e8cd477c9b8631..d519ceb658d6dd 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -130,6 +130,7 @@ class Namespace < ApplicationRecord
            to: :namespace_settings, allow_nil: true
   delegate :show_diff_preview_in_email, :show_diff_preview_in_email?, :show_diff_preview_in_email=,
            to: :namespace_settings
+
   after_save :schedule_sync_event_worker, if: -> { saved_change_to_id? || saved_change_to_parent_id? }
   after_save :reload_namespace_details
 
-- 
GitLab


From c5ca46f572bb0315d23d1efc523aa2d297a536e3 Mon Sep 17 00:00:00 2001
From: Joseph Snyder <joe.snyder@kitware.com>
Date: Thu, 25 Aug 2022 14:15:52 -0400
Subject: [PATCH 3/5] Properly place show_diff_in_email in schema file

Place the entry for diff previews in email in the proper place within
the db/structure.sql file.
---
 db/structure.sql | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/db/structure.sql b/db/structure.sql
index 8aea782ba4b718..b558d104ee973d 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -17818,6 +17818,7 @@ CREATE TABLE namespace_settings (
     subgroup_runner_token_expiration_interval integer,
     project_runner_token_expiration_interval integer,
     exclude_from_free_user_cap boolean DEFAULT false NOT NULL,
+    show_diff_preview_in_email boolean DEFAULT true NOT NULL,
     enabled_git_access_protocol smallint DEFAULT 0 NOT NULL,
     unique_project_download_limit smallint DEFAULT 0 NOT NULL,
     unique_project_download_limit_interval_in_seconds integer DEFAULT 0 NOT NULL,
@@ -17825,7 +17826,6 @@ CREATE TABLE namespace_settings (
     include_for_free_user_cap_preview boolean DEFAULT false NOT NULL,
     unique_project_download_limit_allowlist text[] DEFAULT '{}'::text[] NOT NULL,
     auto_ban_user_on_excessive_projects_download boolean DEFAULT false NOT NULL,
-    show_diff_preview_in_email boolean DEFAULT true NOT NULL,
     CONSTRAINT check_0ba93c78c7 CHECK ((char_length(default_branch_name) <= 255)),
     CONSTRAINT namespace_settings_unique_project_download_limit_allowlist_size CHECK ((cardinality(unique_project_download_limit_allowlist) <= 100))
 );
-- 
GitLab


From 49a556e5c974dc3adcd471be84f5a0ac65a69ecd Mon Sep 17 00:00:00 2001
From: Joseph Snyder <joe.snyder@kitware.com>
Date: Fri, 26 Aug 2022 09:10:41 -0400
Subject: [PATCH 4/5] Add suggested update to namespace_settings

Add a scope to reduce the amount of database calls used as we check
for the setting.
---
 app/models/namespace_setting.rb | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/app/models/namespace_setting.rb b/app/models/namespace_setting.rb
index ef75db485ba2a4..d73b7730ef3c87 100644
--- a/app/models/namespace_setting.rb
+++ b/app/models/namespace_setting.rb
@@ -25,6 +25,8 @@ class NamespaceSetting < ApplicationRecord
 
   before_validation :normalize_default_branch_name
 
+  scope :ancestor_show_diff_preview_in_email, -> (namespace) { where(namespace_id: namespace.self_and_ancestors).select(:show_diff_preview_in_email) }
+
   chronic_duration_attr :runner_token_expiration_interval_human_readable, :runner_token_expiration_interval
   chronic_duration_attr :subgroup_runner_token_expiration_interval_human_readable, :subgroup_runner_token_expiration_interval
   chronic_duration_attr :project_runner_token_expiration_interval_human_readable, :project_runner_token_expiration_interval
@@ -58,11 +60,14 @@ def prevent_sharing_groups_outside_hierarchy
     namespace.root_ancestor.prevent_sharing_groups_outside_hierarchy
   end
 
-  # any ancestor can hide diff content in emails
   def show_diff_preview_in_email?
-    return namespace.parent.show_diff_preview_in_email? && namespace.show_diff_preview_in_email if namespace.has_parent?
+    return show_diff_preview_in_email unless namespace.has_parent?
+
+    all_ancestors_allow_diff_preview_in_email?
+  end
 
-    show_diff_preview_in_email
+  def all_ancestors_allow_diff_preview_in_email?
+    !self.class.ancestor_show_diff_preview_in_email(namespace).collect(&:show_diff_preview_in_email).include? false
   end
 
   private
-- 
GitLab


From 9993a415b817b5cf461ed1f930c2a56e94ce74b1 Mon Sep 17 00:00:00 2001
From: Joseph Snyder <joe.snyder@kitware.com>
Date: Tue, 30 Aug 2022 10:45:53 -0400
Subject: [PATCH 5/5] Additional review fixes

Make the spec descriptions have better flow and better describe the
content of each part of the test.

Update memoization formatting to follow new suggestion.

Add new command for all ancestors query to perform the search entirely
in the database. Remove the unneeded scope attribute and make the
ancestor searching function private
---
 app/models/namespace_setting.rb       |  8 +++---
 app/models/project_setting.rb         | 12 ++++-----
 spec/models/namespace_setting_spec.rb | 17 +++++++------
 spec/models/project_setting_spec.rb   | 35 ++++++++++++++++++---------
 4 files changed, 41 insertions(+), 31 deletions(-)

diff --git a/app/models/namespace_setting.rb b/app/models/namespace_setting.rb
index d73b7730ef3c87..6a87fba57acfdd 100644
--- a/app/models/namespace_setting.rb
+++ b/app/models/namespace_setting.rb
@@ -25,8 +25,6 @@ class NamespaceSetting < ApplicationRecord
 
   before_validation :normalize_default_branch_name
 
-  scope :ancestor_show_diff_preview_in_email, -> (namespace) { where(namespace_id: namespace.self_and_ancestors).select(:show_diff_preview_in_email) }
-
   chronic_duration_attr :runner_token_expiration_interval_human_readable, :runner_token_expiration_interval
   chronic_duration_attr :subgroup_runner_token_expiration_interval_human_readable, :subgroup_runner_token_expiration_interval
   chronic_duration_attr :project_runner_token_expiration_interval_human_readable, :project_runner_token_expiration_interval
@@ -66,12 +64,12 @@ def show_diff_preview_in_email?
     all_ancestors_allow_diff_preview_in_email?
   end
 
+  private
+
   def all_ancestors_allow_diff_preview_in_email?
-    !self.class.ancestor_show_diff_preview_in_email(namespace).collect(&:show_diff_preview_in_email).include? false
+    !self.class.where(namespace_id: namespace.self_and_ancestors, show_diff_preview_in_email: false).exists?
   end
 
-  private
-
   def normalize_default_branch_name
     self.default_branch_name = default_branch_name.presence
   end
diff --git a/app/models/project_setting.rb b/app/models/project_setting.rb
index a216de32ab8f61..f5c346eda30566 100644
--- a/app/models/project_setting.rb
+++ b/app/models/project_setting.rb
@@ -50,15 +50,13 @@ def human_squash_option
   end
 
   def show_diff_preview_in_email?
-    strong_memoize(:show_diff_preview_in_email) do
-      # disabling in the namespace overrides the project setting
-      if project.group
-        super && project.group&.show_diff_preview_in_email?
-      else
-        !!super
-      end
+    if project.group
+      super && project.group&.show_diff_preview_in_email?
+    else
+      !!super
     end
   end
+  strong_memoize_attr :show_diff_preview_in_email
 
   private
 
diff --git a/spec/models/namespace_setting_spec.rb b/spec/models/namespace_setting_spec.rb
index 8b795405285560..9fce65c9a5fb87 100644
--- a/spec/models/namespace_setting_spec.rb
+++ b/spec/models/namespace_setting_spec.rb
@@ -151,20 +151,23 @@
       end
     end
 
-    context 'when an ancestor has disabled diff previews' do
-      let(:settings) { create(:namespace_settings, show_diff_preview_in_email: false) }
+    context 'when a group has parent groups' do
       let(:grandparent) { create(:group, namespace_settings: settings) }
       let(:parent)      { create(:group, parent: grandparent) }
       let!(:group) { create(:group, parent: parent) }
 
-      it 'returns false' do
-        expect(group.show_diff_preview_in_email?).to be_falsey
+      context "when a parent group has disabled diff previews" do
+        let(:settings) { create(:namespace_settings, show_diff_preview_in_email: false) }
+
+        it 'returns false' do
+          expect(group.show_diff_preview_in_email?).to be_falsey
+        end
       end
 
-      context 'when all ancestors have enabled diff previews' do
-        it 'returns true' do
-          grandparent.update_attribute(:show_diff_preview_in_email, true)
+      context 'when all parent groups have enabled diff previews' do
+        let(:settings) { create(:namespace_settings, show_diff_preview_in_email: true) }
 
+        it 'returns true' do
           expect(group.show_diff_preview_in_email?).to be_truthy
         end
       end
diff --git a/spec/models/project_setting_spec.rb b/spec/models/project_setting_spec.rb
index e2569bc3fb4e58..a09ae7ec7aed6e 100644
--- a/spec/models/project_setting_spec.rb
+++ b/spec/models/project_setting_spec.rb
@@ -65,32 +65,43 @@ def valid_target_platform_combinations
   end
 
   describe '#show_diff_preview_in_email?' do
-    context 'when not a subgroup' do
-      it 'returns false' do
-        settings = create(:project_setting, show_diff_preview_in_email: false)
-        project = create(:project, project_setting: settings)
-        expect(project).not_to be_show_diff_preview_in_email
+    context 'when a project is a top-level namespace' do
+      let(:project_settings ) { create(:project_setting, show_diff_preview_in_email: false) }
+      let(:project) { create(:project, project_setting: project_settings) }
+
+      context 'when show_diff_preview_in_email is disabled' do
+        it 'returns false' do
+          expect(project).not_to be_show_diff_preview_in_email
+        end
       end
 
-      it 'returns true' do
-        settings = create(:project_setting, show_diff_preview_in_email: true)
-        project = create(:project, project_setting: settings)
+      context 'when show_diff_preview_in_email is enabled' do
+        let(:project_settings ) { create(:project_setting, show_diff_preview_in_email: true) }
+
+        it 'returns true' do
+          settings = create(:project_setting, show_diff_preview_in_email: true)
+          project = create(:project, project_setting: settings)
 
-        expect(project).to be_show_diff_preview_in_email
+          expect(project).to be_show_diff_preview_in_email
+        end
       end
     end
 
-    context 'when a parent group has disabled diff previews' do
+    context 'when a parent group has a parent group' do
       let(:namespace_settings) { create(:namespace_settings, show_diff_preview_in_email: false) }
       let(:project_settings) { create(:project_setting, show_diff_preview_in_email: true) }
       let(:group) { create(:group, namespace_settings: namespace_settings) }
       let!(:project) { create(:project, namespace_id: group.id, project_setting: project_settings) }
 
-      it 'returns false' do
-        expect(project).not_to be_show_diff_preview_in_email
+      context 'when show_diff_preview_in_email is disabled for the parent group' do
+        it 'returns false' do
+          expect(project).not_to be_show_diff_preview_in_email
+        end
       end
 
       context 'when all ancestors have enabled diff previews' do
+        let(:namespace_settings) { create(:namespace_settings, show_diff_preview_in_email: true) }
+
         it 'returns true' do
           group.update_attribute(:show_diff_preview_in_email, true)
 
-- 
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