Add issuable state count type for Project grpahql

- reuse issue resolver fields
- Use IssuablesCountForState

app/graphql/resolvers/issue_resolver_fields.rb

+# frozen_string_literal: true
+
+module Resolvers
+  module IssueResolverFields
+    extend ActiveSupport::Concern
+
+    prepended do
+      argument :iid, GraphQL::STRING_TYPE,
+                required: false,
+                description: 'IID of the issue. For example, "1"'
+
+      argument :iids, [GraphQL::STRING_TYPE],
+                required: false,
+                description: 'List of IIDs of issues. For example, [1, 2]'
+      argument :state, Types::IssuableStateEnum,
+                required: false,
+                description: 'Current state of this issue'
+      argument :label_name, GraphQL::STRING_TYPE.to_list_type,
+                required: false,
+                description: 'Labels applied to this issue'
+      argument :milestone_title, GraphQL::STRING_TYPE.to_list_type,
+                required: false,
+                description: 'Milestones applied to this issue'
+      argument :assignee_username, GraphQL::STRING_TYPE,
+                required: false,
+                description: 'Username of a user assigned to the issues'
+      argument :assignee_id, GraphQL::STRING_TYPE,
+                required: false,
+                description: 'ID of a user assigned to the issues, "none" and "any" values supported'
+      argument :created_before, Types::TimeType,
+                required: false,
+                description: 'Issues created before this date'
+      argument :created_after, Types::TimeType,
+                required: false,
+                description: 'Issues created after this date'
+      argument :updated_before, Types::TimeType,
+                required: false,
+                description: 'Issues updated before this date'
+      argument :updated_after, Types::TimeType,
+                required: false,
+                description: 'Issues updated after this date'
+      argument :closed_before, Types::TimeType,
+                required: false,
+                description: 'Issues closed before this date'
+      argument :closed_after, Types::TimeType,
+                required: false,
+                description: 'Issues closed after this date'
+      argument :search, GraphQL::STRING_TYPE,
+                required: false,
+                description: 'Search query for issue title or description'
+      argument :sort, Types::IssueSortEnum,
+                description: 'Sort issues by this criteria',
+                required: false,
+                default_value: 'created_desc'
+      argument :types, [Types::IssueTypeEnum],
+                as: :issue_types,
+                description: 'Filter issues by the given issue types',
+                required: false
+    end
+  end
+end

app/graphql/resolvers/issue_status_counts_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  class IssueStatusCountsResolver < BaseResolver
+    prepend Resolvers::IssueResolverFields
+
+    type Types::IssueStatusCountsType, null: true
+
+    def resolve(**args)
+      # The project could have been loaded in batch by `BatchLoader`.
+      # At this point we need the `id` of the project to query for issues, so
+      # make sure it's loaded and not `nil` before continuing.
+      parent = object.respond_to?(:sync) ? object.sync : object
+      return Issue.none if parent.nil?
+
+      # Will need to be be made group & namespace aware with
+      # https://gitlab.com/gitlab-org/gitlab-foss/issues/54520
+      args[:iids] ||= [args.delete(:iid)].compact if args[:iid]
+      args[:attempt_project_search_optimizations] = true if args[:search].present?
+
+      finder = IssuesFinder.new(current_user, args)
+
+      Gitlab::IssuablesCountForState.new(finder, parent)
+    end
+  end
+end

app/graphql/resolvers/issues_resolver.rb

@@ -2,57 +2,7 @@
 
 module Resolvers
   class IssuesResolver < BaseResolver
-    argument :iid, GraphQL::STRING_TYPE,
-              required: false,
-              description: 'IID of the issue. For example, "1"'
-
-    argument :iids, [GraphQL::STRING_TYPE],
-              required: false,
-              description: 'List of IIDs of issues. For example, [1, 2]'
-    argument :state, Types::IssuableStateEnum,
-              required: false,
-              description: 'Current state of this issue'
-    argument :label_name, GraphQL::STRING_TYPE.to_list_type,
-              required: false,
-              description: 'Labels applied to this issue'
-    argument :milestone_title, GraphQL::STRING_TYPE.to_list_type,
-              required: false,
-              description: 'Milestones applied to this issue'
-    argument :assignee_username, GraphQL::STRING_TYPE,
-              required: false,
-              description: 'Username of a user assigned to the issues'
-    argument :assignee_id, GraphQL::STRING_TYPE,
-              required: false,
-              description: 'ID of a user assigned to the issues, "none" and "any" values supported'
-    argument :created_before, Types::TimeType,
-              required: false,
-              description: 'Issues created before this date'
-    argument :created_after, Types::TimeType,
-              required: false,
-              description: 'Issues created after this date'
-    argument :updated_before, Types::TimeType,
-              required: false,
-              description: 'Issues updated before this date'
-    argument :updated_after, Types::TimeType,
-              required: false,
-              description: 'Issues updated after this date'
-    argument :closed_before, Types::TimeType,
-              required: false,
-              description: 'Issues closed before this date'
-    argument :closed_after, Types::TimeType,
-              required: false,
-              description: 'Issues closed after this date'
-    argument :search, GraphQL::STRING_TYPE,
-              required: false,
-              description: 'Search query for issue title or description'
-    argument :sort, Types::IssueSortEnum,
-              description: 'Sort issues by this criteria',
-              required: false,
-              default_value: 'created_desc'
-    argument :types, [Types::IssueTypeEnum],
-              as: :issue_types,
-              description: 'Filter issues by the given issue types',
-              required: false
+    prepend Resolvers::IssueResolverFields
 
     type Types::IssueType, null: true
 

app/graphql/types/issue_status_counts_type.rb

+# frozen_string_literal: true
+
+module Types
+  class IssueStatusCountsType < BaseObject
+    graphql_name 'IssueStatusCountsType'
+    description "Represents total number of issues for the represented categories"
+
+    authorize :read_issue
+
+    ::Gitlab::IssuablesCountForState::STATES.each do |status|
+      field status,
+            GraphQL::INT_TYPE,
+            null: true,
+            description: "Number of issues with status #{status.upcase} for the project"
+    end
+  end
+end

app/graphql/types/project_type.rb

@@ -148,6 +148,12 @@ module Types
           description: 'Issues of the project',
           resolver: Resolvers::IssuesResolver
 
+    field :issue_status_counts,
+          Types::IssueStatusCountsType,
+          null: true,
+          description: 'Counts of issues by status for the project',
+          resolver: Resolvers::IssueStatusCountsResolver
+
     field :milestones, Types::MilestoneType.connection_type, null: true,
           description: 'Milestones of the project',
           resolver: Resolvers::ProjectMilestonesResolver
@@ -164,8 +170,8 @@ module Types
           resolver: Resolvers::EnvironmentsResolver
 
     field :sast_ci_configuration, ::Types::CiConfiguration::Sast::Type, null: true,
-      description: 'SAST CI configuration for the project',
-      resolver: ::Resolvers::CiConfiguration::SastResolver
+          description: 'SAST CI configuration for the project',
+          resolver: ::Resolvers::CiConfiguration::SastResolver
 
     field :issue,
           Types::IssueType,

lib/gitlab/issuables_count_for_state.rb

@@ -9,9 +9,16 @@ module Gitlab
     # The state values that can be safely casted to a Symbol.
     STATES = %w[opened closed merged all].freeze
 
+    attr_reader :project
+
+    def self.declarative_policy_class
+      'IssuablePolicy'
+    end
+
     # finder - The finder class to use for retrieving the issuables.
-    def initialize(finder)
+    def initialize(finder, project = nil)
       @finder = finder
+      @project = project
       @cache = Gitlab::SafeRequestStore[CACHE_KEY] ||= initialize_cache
     end
 
@@ -19,6 +26,11 @@ module Gitlab
       self[state || :opened]
     end
 
+    # Define method for each status
+    STATES.each do |status|
+      define_method(status) { self[status] }
+    end
+
     # Returns the count for the given state.
     #
     # state - The name of the state as either a String or a Symbol.