Update Discussion mutations to use new Global IDs

This changes the Discussion mutation to use the new `GlobalID` types for
arguments, with the temporary compatibility layer added in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/36209.

https://gitlab.com/gitlab-org/gitlab/-/issues/268042

.rubocop_todo.yml

@@ -1281,7 +1281,6 @@ Graphql/IDType:
     - 'app/graphql/mutations/boards/create.rb'
     - 'app/graphql/mutations/boards/issues/issue_move_list.rb'
     - 'app/graphql/mutations/boards/lists/update.rb'
-    - 'app/graphql/mutations/discussions/toggle_resolve.rb'
     - 'app/graphql/mutations/issues/update.rb'
     - 'app/graphql/mutations/metrics/dashboard/annotations/delete.rb'
     - 'app/graphql/mutations/snippets/destroy.rb'

app/graphql/mutations/discussions/toggle_resolve.rb

@@ -8,7 +8,7 @@ module Mutations
       description 'Toggles the resolved state of a discussion'
 
       argument :id,
-                GraphQL::ID_TYPE,
+                Types::GlobalIDType[Discussion],
                 required: true,
                 description: 'The global id of the discussion'
 
@@ -54,7 +54,10 @@ module Mutations
       end
 
       def find_object(id:)
-        GitlabSchema.object_from_id(id, expected_type: ::Discussion)
+        # TODO: remove explicit coercion once compatibility layer has been removed
+        # See: https://gitlab.com/gitlab-org/gitlab/-/issues/257883
+        id = Types::GlobalIDType[Discussion].coerce_isolated_input(id)
+        GitlabSchema.find_by_gid(id)
       end
 
       def resolve!(discussion)

changelogs/unreleased/268042-graphql-use-new-global_id-for-discussion-mutations.yml

+---
+title: Update GraphQL discussionToggleResolve mutation input id to be more type-specific
+merge_request: 45346
+author:
+type: changed

doc/api/graphql/reference/gitlab_schema.graphql

@@ -5870,7 +5870,7 @@ input DiscussionToggleResolveInput {
   """
   The global id of the discussion
   """
-  id: ID!
+  id: DiscussionID!
 
   """
   Will resolve the discussion when true, and unresolve the discussion when false

doc/api/graphql/reference/gitlab_schema.json

@@ -16105,7 +16105,7 @@
                 "name": null,
                 "ofType": {
                   "kind": "SCALAR",
-                  "name": "ID",
+                  "name": "DiscussionID",
                   "ofType": null
                 }
               },

spec/graphql/mutations/discussions/toggle_resolve_spec.rb

@@ -50,8 +50,8 @@ RSpec.describe Mutations::Discussions::ToggleResolve do
 
           it 'raises an error' do
             expect { subject }.to raise_error(
-              Gitlab::Graphql::Errors::ArgumentError,
-              "#{discussion.to_global_id} is not a valid ID for Discussion."
+              GraphQL::CoercionError,
+              "\"#{discussion.to_global_id}\" does not represent an instance of Discussion"
             )
           end
         end