Change the linkType argument for issueLinks query to enum

doc/api/graphql/reference/gitlab_schema.graphql

@@ -12725,7 +12725,7 @@ type Vulnerability {
     """
     Filter issue links by link type
     """
-    linkType: [VulnerabilityIssueLinkType!]
+    linkType: VulnerabilityIssueLinkType
   ): VulnerabilityIssueLinkConnection!
 
   """

doc/api/graphql/reference/gitlab_schema.json

@@ -37400,17 +37400,9 @@
                   "name": "linkType",
                   "description": "Filter issue links by link type",
                   "type": {
-                    "kind": "LIST",
-                    "name": null,
-                    "ofType": {
-                      "kind": "NON_NULL",
-                      "name": null,
-                      "ofType": {
-                        "kind": "ENUM",
-                        "name": "VulnerabilityIssueLinkType",
-                        "ofType": null
-                      }
-                    }
+                    "kind": "ENUM",
+                    "name": "VulnerabilityIssueLinkType",
+                    "ofType": null
                   },
                   "defaultValue": null
                 },

ee/app/graphql/resolvers/vulnerabilities/issue_links_resolver.rb

@@ -5,7 +5,7 @@ module Resolvers
     class IssueLinksResolver < BaseResolver
       type Types::Vulnerability::IssueLinkType, null: true
 
-      argument :link_type, [Types::Vulnerability::IssueLinkTypeEnum],
+      argument :link_type, Types::Vulnerability::IssueLinkTypeEnum,
                required: false,
                description: 'Filter issue links by link type'
 

ee/changelogs/unreleased/213742_fix_link_type_argument_type_of_issue_links_resolver.yml

+---
+title: Change the linkType argument for issueLinks query to enum
+merge_request: 33828
+author:
+type: fixed