Remove code related to object hierarchy in MySQL

These are not required because MySQL is not
supported anymore

4 files changed, 121 insertions, 177 deletions

diff --git a/lib/gitlab/object_hierarchy.rb b/lib/gitlab/object_hierarchy.rb
index 38b32770e90..c06f106ffe1 100644
--- a/lib/gitlab/object_hierarchy.rb
+++ b/lib/gitlab/object_hierarchy.rb
@@ -32,11 +32,6 @@ module Gitlab
     # Returns the maximum depth starting from the base
     # A base object with no children has a maximum depth of `1`
     def max_descendants_depth
-      unless hierarchy_supported?
-        # This makes the return value consistent with the case where hierarchy is supported
-        return descendants_base.exists? ? 1 : nil
-      end
-
       base_and_descendants(with_depth: true).maximum(DEPTH_COLUMN)
     end
 
@@ -66,8 +61,6 @@ module Gitlab
     # each parent.
     # rubocop: disable CodeReuse/ActiveRecord
     def base_and_ancestors(upto: nil, hierarchy_order: nil)
-      return ancestors_base unless hierarchy_supported?
-
       recursive_query = base_and_ancestors_cte(upto, hierarchy_order).apply_to(model.all)
       recursive_query = recursive_query.order(depth: hierarchy_order) if hierarchy_order
 
@@ -81,10 +74,6 @@ module Gitlab
     # When `with_depth` is `true`, a `depth` column is included where it starts with `1` for the base objects
     # and incremented as we go down the descendant tree
     def base_and_descendants(with_depth: false)
-      unless hierarchy_supported?
-        return with_depth ? descendants_base.select("1 as #{DEPTH_COLUMN}", objects_table[Arel.star]) : descendants_base
-      end
-
       read_only(base_and_descendants_cte(with_depth: with_depth).apply_to(model.all))
     end
 
@@ -112,8 +101,6 @@ module Gitlab
     # If nested objects are not supported, ancestors_base is returned.
     # rubocop: disable CodeReuse/ActiveRecord
     def all_objects
-      return ancestors_base unless hierarchy_supported?
-
       ancestors = base_and_ancestors_cte
       descendants = base_and_descendants_cte
 
@@ -135,10 +122,6 @@ module Gitlab
 
     private
 
-    def hierarchy_supported?
-      Gitlab::Database.postgresql?
-    end
-
     # rubocop: disable CodeReuse/ActiveRecord
     def base_and_ancestors_cte(stop_id = nil, hierarchy_order = nil)
       cte = SQL::RecursiveCTE.new(:base_and_ancestors)
diff --git a/lib/gitlab/project_authorizations.rb b/lib/gitlab/project_authorizations.rb
new file mode 100644
index 00000000000..a9270cd536e
--- /dev/null
+++ b/lib/gitlab/project_authorizations.rb
@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+# This class relies on Common Table Expressions to efficiently get all data,
+# including data for nested groups.
+module Gitlab
+  class ProjectAuthorizations
+    attr_reader :user
+
+    # user - The User object for which to calculate the authorizations.
+    def initialize(user)
+      @user = user
+    end
+
+    def calculate
+      cte = recursive_cte
+      cte_alias = cte.table.alias(Group.table_name)
+      projects = Project.arel_table
+      links = ProjectGroupLink.arel_table
+
+      relations = [
+        # The project a user has direct access to.
+        user.projects.select_for_project_authorization,
+
+        # The personal projects of the user.
+        user.personal_projects.select_as_maintainer_for_project_authorization,
+
+        # Projects that belong directly to any of the groups the user has
+        # access to.
+        Namespace
+          .unscoped
+          .select([alias_as_column(projects[:id], 'project_id'),
+                   cte_alias[:access_level]])
+          .from(cte_alias)
+          .joins(:projects),
+
+        # Projects shared with any of the namespaces the user has access to.
+        Namespace
+          .unscoped
+          .select([
+            links[:project_id],
+            least(cte_alias[:access_level], links[:group_access], 'access_level')
+          ])
+          .from(cte_alias)
+          .joins('INNER JOIN project_group_links ON project_group_links.group_id = namespaces.id')
+          .joins('INNER JOIN projects ON projects.id = project_group_links.project_id')
+          .joins('INNER JOIN namespaces p_ns ON p_ns.id = projects.namespace_id')
+          .where('p_ns.share_with_group_lock IS FALSE')
+      ]
+
+      ProjectAuthorization
+        .unscoped
+        .with
+        .recursive(cte.to_arel)
+        .select_from_union(relations)
+    end
+
+    private
+
+    # Builds a recursive CTE that gets all the groups the current user has
+    # access to, including any nested groups.
+    def recursive_cte
+      cte = Gitlab::SQL::RecursiveCTE.new(:namespaces_cte)
+      members = Member.arel_table
+      namespaces = Namespace.arel_table
+
+      # Namespaces the user is a member of.
+      cte << user.groups
+        .select([namespaces[:id], members[:access_level]])
+        .except(:order)
+
+      # Sub groups of any groups the user is a member of.
+      cte << Group.select([
+          namespaces[:id],
+          greatest(members[:access_level], cte.table[:access_level], 'access_level')
+        ])
+        .joins(join_cte(cte))
+        .joins(join_members)
+        .except(:order)
+
+      cte
+    end
+
+    # Builds a LEFT JOIN to join optional memberships onto the CTE.
+    def join_members
+      members = Member.arel_table
+      namespaces = Namespace.arel_table
+
+      cond = members[:source_id]
+        .eq(namespaces[:id])
+        .and(members[:source_type].eq('Namespace'))
+        .and(members[:requested_at].eq(nil))
+        .and(members[:user_id].eq(user.id))
+
+      Arel::Nodes::OuterJoin.new(members, Arel::Nodes::On.new(cond))
+    end
+
+    # Builds an INNER JOIN to join namespaces onto the CTE.
+    def join_cte(cte)
+      namespaces = Namespace.arel_table
+      cond = cte.table[:id].eq(namespaces[:parent_id])
+
+      Arel::Nodes::InnerJoin.new(cte.table, Arel::Nodes::On.new(cond))
+    end
+
+    def greatest(left, right, column_alias)
+      sql_function('GREATEST', [left, right], column_alias)
+    end
+
+    def least(left, right, column_alias)
+      sql_function('LEAST', [left, right], column_alias)
+    end
+
+    def sql_function(name, args, column_alias)
+      alias_as_column(Arel::Nodes::NamedFunction.new(name, args), column_alias)
+    end
+
+    def alias_as_column(value, alias_to)
+      Arel::Nodes::As.new(value, Arel::Nodes::SqlLiteral.new(alias_to))
+    end
+  end
+end
diff --git a/lib/gitlab/project_authorizations/with_nested_groups.rb b/lib/gitlab/project_authorizations/with_nested_groups.rb
deleted file mode 100644
index 2372a316ab0..00000000000
--- a/lib/gitlab/project_authorizations/with_nested_groups.rb
+++ /dev/null
@@ -1,125 +0,0 @@
-# frozen_string_literal: true
-
-module Gitlab
-  module ProjectAuthorizations
-    # Calculating new project authorizations when supporting nested groups.
-    #
-    # This class relies on Common Table Expressions to efficiently get all data,
-    # including data for nested groups. As a result this class can only be used
-    # on PostgreSQL.
-    class WithNestedGroups
-      attr_reader :user
-
-      # user - The User object for which to calculate the authorizations.
-      def initialize(user)
-        @user = user
-      end
-
-      def calculate
-        cte = recursive_cte
-        cte_alias = cte.table.alias(Group.table_name)
-        projects = Project.arel_table
-        links = ProjectGroupLink.arel_table
-
-        relations = [
-          # The project a user has direct access to.
-          user.projects.select_for_project_authorization,
-
-          # The personal projects of the user.
-          user.personal_projects.select_as_maintainer_for_project_authorization,
-
-          # Projects that belong directly to any of the groups the user has
-          # access to.
-          Namespace
-            .unscoped
-            .select([alias_as_column(projects[:id], 'project_id'),
-                     cte_alias[:access_level]])
-            .from(cte_alias)
-            .joins(:projects),
-
-          # Projects shared with any of the namespaces the user has access to.
-          Namespace
-            .unscoped
-            .select([links[:project_id],
-                     least(cte_alias[:access_level],
-                           links[:group_access],
-                           'access_level')])
-            .from(cte_alias)
-            .joins('INNER JOIN project_group_links ON project_group_links.group_id = namespaces.id')
-            .joins('INNER JOIN projects ON projects.id = project_group_links.project_id')
-            .joins('INNER JOIN namespaces p_ns ON p_ns.id = projects.namespace_id')
-            .where('p_ns.share_with_group_lock IS FALSE')
-        ]
-
-        ProjectAuthorization
-          .unscoped
-          .with
-          .recursive(cte.to_arel)
-          .select_from_union(relations)
-      end
-
-      private
-
-      # Builds a recursive CTE that gets all the groups the current user has
-      # access to, including any nested groups.
-      def recursive_cte
-        cte = Gitlab::SQL::RecursiveCTE.new(:namespaces_cte)
-        members = Member.arel_table
-        namespaces = Namespace.arel_table
-
-        # Namespaces the user is a member of.
-        cte << user.groups
-          .select([namespaces[:id], members[:access_level]])
-          .except(:order)
-
-        # Sub groups of any groups the user is a member of.
-        cte << Group.select([namespaces[:id],
-                             greatest(members[:access_level],
-                                      cte.table[:access_level], 'access_level')])
-          .joins(join_cte(cte))
-          .joins(join_members)
-          .except(:order)
-
-        cte
-      end
-
-      # Builds a LEFT JOIN to join optional memberships onto the CTE.
-      def join_members
-        members = Member.arel_table
-        namespaces = Namespace.arel_table
-
-        cond = members[:source_id]
-          .eq(namespaces[:id])
-          .and(members[:source_type].eq('Namespace'))
-          .and(members[:requested_at].eq(nil))
-          .and(members[:user_id].eq(user.id))
-
-        Arel::Nodes::OuterJoin.new(members, Arel::Nodes::On.new(cond))
-      end
-
-      # Builds an INNER JOIN to join namespaces onto the CTE.
-      def join_cte(cte)
-        namespaces = Namespace.arel_table
-        cond = cte.table[:id].eq(namespaces[:parent_id])
-
-        Arel::Nodes::InnerJoin.new(cte.table, Arel::Nodes::On.new(cond))
-      end
-
-      def greatest(left, right, column_alias)
-        sql_function('GREATEST', [left, right], column_alias)
-      end
-
-      def least(left, right, column_alias)
-        sql_function('LEAST', [left, right], column_alias)
-      end
-
-      def sql_function(name, args, column_alias)
-        alias_as_column(Arel::Nodes::NamedFunction.new(name, args), column_alias)
-      end
-
-      def alias_as_column(value, alias_to)
-        Arel::Nodes::As.new(value, Arel::Nodes::SqlLiteral.new(alias_to))
-      end
-    end
-  end
-end
diff --git a/lib/gitlab/project_authorizations/without_nested_groups.rb b/lib/gitlab/project_authorizations/without_nested_groups.rb
deleted file mode 100644
index 50b41b17649..00000000000
--- a/lib/gitlab/project_authorizations/without_nested_groups.rb
+++ /dev/null
@@ -1,35 +0,0 @@
-# frozen_string_literal: true
-
-module Gitlab
-  module ProjectAuthorizations
-    # Calculating new project authorizations when not supporting nested groups.
-    class WithoutNestedGroups
-      attr_reader :user
-
-      # user - The User object for which to calculate the authorizations.
-      def initialize(user)
-        @user = user
-      end
-
-      def calculate
-        relations = [
-          # Projects the user is a direct member of
-          user.projects.select_for_project_authorization,
-
-          # Personal projects
-          user.personal_projects.select_as_maintainer_for_project_authorization,
-
-          # Projects of groups the user is a member of
-          user.groups_projects.select_for_project_authorization,
-
-          # Projects shared with groups the user is a member of
-          user.groups.joins(:shared_projects).select_for_project_authorization
-        ]
-
-        ProjectAuthorization
-          .unscoped
-          .select_from_union(relations)
-      end
-    end
-  end
-end