Allow empty search string for iterations search

EE: true

doc/api/graphql/reference/index.md

@@ -11107,7 +11107,7 @@ four standard [pagination arguments](#connection-pagination-arguments):
 | <a id="groupiterationsin"></a>`in` | [`[IterationSearchableField!]`](#iterationsearchablefield) | Fields in which the fuzzy-search should be performed with the query given in the argument `search`. Defaults to `[title]`. |
 | <a id="groupiterationsincludeancestors"></a>`includeAncestors` | [`Boolean`](#boolean) | Whether to include ancestor iterations. Defaults to true. |
 | <a id="groupiterationsiterationcadenceids"></a>`iterationCadenceIds` | [`[IterationsCadenceID!]`](#iterationscadenceid) | Global iteration cadence IDs by which to look up the iterations. |
-| <a id="groupiterationssearch"></a>`search` | [`String`](#string) | Query used for fuzzy-searching in the fields selected in the argument `in`. |
+| <a id="groupiterationssearch"></a>`search` | [`String`](#string) | Query used for fuzzy-searching in the fields selected in the argument `in`. Returns all iterations if empty. |
 | <a id="groupiterationssort"></a>`sort` | [`IterationSort`](#iterationsort) | List iterations by sort order. If unspecified, an arbitrary order (subject to change) is used. |
 | <a id="groupiterationsstartdate"></a>`startDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.start. |
 | <a id="groupiterationsstate"></a>`state` | [`IterationState`](#iterationstate) | Filter iterations by state. |
@@ -13821,7 +13821,7 @@ four standard [pagination arguments](#connection-pagination-arguments):
 | <a id="projectiterationsin"></a>`in` | [`[IterationSearchableField!]`](#iterationsearchablefield) | Fields in which the fuzzy-search should be performed with the query given in the argument `search`. Defaults to `[title]`. |
 | <a id="projectiterationsincludeancestors"></a>`includeAncestors` | [`Boolean`](#boolean) | Whether to include ancestor iterations. Defaults to true. |
 | <a id="projectiterationsiterationcadenceids"></a>`iterationCadenceIds` | [`[IterationsCadenceID!]`](#iterationscadenceid) | Global iteration cadence IDs by which to look up the iterations. |
-| <a id="projectiterationssearch"></a>`search` | [`String`](#string) | Query used for fuzzy-searching in the fields selected in the argument `in`. |
+| <a id="projectiterationssearch"></a>`search` | [`String`](#string) | Query used for fuzzy-searching in the fields selected in the argument `in`. Returns all iterations if empty. |
 | <a id="projectiterationssort"></a>`sort` | [`IterationSort`](#iterationsort) | List iterations by sort order. If unspecified, an arbitrary order (subject to change) is used. |
 | <a id="projectiterationsstartdate"></a>`startDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.start. |
 | <a id="projectiterationsstate"></a>`state` | [`IterationState`](#iterationstate) | Filter iterations by state. |

ee/app/graphql/resolvers/iterations_resolver.rb

@@ -17,7 +17,7 @@ module Resolvers
 
     argument :search, GraphQL::Types::String,
              required: false,
-             description: 'Query used for fuzzy-searching in the fields selected in the argument `in`.'
+             description: 'Query used for fuzzy-searching in the fields selected in the argument `in`. Returns all iterations if empty.'
 
     argument :in, [Types::IterationSearchableFieldEnum],
              required: false,
@@ -72,10 +72,6 @@ module Resolvers
       if args[:title].present? && (args[:search].present? || args[:in].present?)
         raise Gitlab::Graphql::Errors::ArgumentError, "'title' is deprecated in favor of 'search'. Please use 'search'."
       end
-
-      if !args[:search].present? && args[:in].present?
-        raise Gitlab::Graphql::Errors::ArgumentError, "'search' must be specified when using 'in' argument."
-      end
     end
 
     def handle_search_params!(args)

ee/spec/graphql/resolvers/iterations_resolver_spec.rb

@@ -66,6 +66,8 @@ RSpec.describe Resolvers::IterationsResolver do
           context 'with search and in parameters' do
             where(:search, :fields_to_search, :expected_iterations) do
               ''          | []                       | lazy { all_iterations }
+              ''          | [:title]                 | lazy { all_iterations }
+              ''          | [:title, :cadence_title] | lazy { all_iterations }
               'iteration' | nil                      | lazy { plan_cadence.iterations }
               'iteration' | []                       | lazy { plan_cadence.iterations }
               'iteration' | [:title]                 | lazy { plan_cadence.iterations }
@@ -94,12 +96,6 @@ RSpec.describe Resolvers::IterationsResolver do
               end
             end
 
-            it "raises an error when 'in' is specified but 'search' is not" do
-              expect do
-                resolve_group_iterations({ in: [:title] })
-              end.to raise_error(Gitlab::Graphql::Errors::ArgumentError, "'search' must be specified when using 'in' argument.")
-            end
-
             it "uses 'search' and 'in' arguments to search title" do
               expect(resolve_group_iterations({ title: 'iteration' }).items).to contain_exactly(*plan_cadence.iterations)
             end