Remove subscribed field from APIs listing issues

Remove the subscribed field from todos, related issues, and epic issues
API. We do not intend to include this in APIs that render multiple
issuables because this triggers Markdown processing for all notes and
is very expensive to compute.

Changelog: fixed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/60981

changelogs/unreleased/211373-remove-subscribed-from-other-issue-lists.yml

+---
+title: Remove subscribed field from todos, related issues, and epic issues API
+merge_request: 60981
+author:
+type: fixed

doc/api/epic_issues.md

@@ -107,7 +107,6 @@ Example response:
       "award_emoji": "http://localhost:3001/api/v4/projects/8/issues/6/award_emoji",
       "project": "http://localhost:3001/api/v4/projects/8"
     },
-    "subscribed": true,
     "epic_issue_id": 2
   }
 ]

doc/api/issue_links.md

@@ -51,7 +51,6 @@ Parameters:
     "description" : null,
     "updated_at" : "2016-01-07T12:44:33.959Z",
     "milestone" : null,
-    "subscribed" : true,
     "user_notes_count": 0,
     "due_date": null,
     "web_url": "http://example.com/example/example/issues/14",

doc/api/todos.md

@@ -102,7 +102,6 @@ Example Response:
       },
       "merge_when_pipeline_succeeds": false,
       "merge_status": "cannot_be_merged",
-      "subscribed": true,
       "user_notes_count": 7
     },
     "target_url": "https://gitlab.example.com/gitlab-org/gitlab-foss/-/merge_requests/7",
@@ -176,7 +175,6 @@ Example Response:
       },
       "merge_when_pipeline_succeeds": false,
       "merge_status": "cannot_be_merged",
-      "subscribed": true,
       "user_notes_count": 7
     },
     "target_url": "https://gitlab.example.com/gitlab-org/gitlab-foss/-/merge_requests/7",

ee/lib/api/epic_issues.rb

@@ -71,7 +71,8 @@ module API
 
           present paginate(related_issues(epic)),
             with: EE::API::Entities::EpicIssue,
-            current_user: current_user
+            current_user: current_user,
+            include_subscribed: false
         end
       end
 

lib/api/issue_links.rb

@@ -21,12 +21,12 @@ module API
         related_issues = source_issue.related_issues(current_user) do |issues|
           issues.with_api_entity_associations.preload_awardable
         end
-        related_issues.each { |issue| issue.lazy_subscription(current_user, user_project) } # preload subscriptions
 
         present related_issues,
                 with: Entities::RelatedIssue,
                 current_user: current_user,
-                project: user_project
+                project: user_project,
+                include_subscribed: false
       end
 
       desc 'Relate issues' do

lib/api/todos.rb

@@ -79,7 +79,7 @@ module API
             next unless collection
 
             targets = collection.map(&:target)
-            options[type] = { issuable_metadata: Gitlab::IssuableMetadata.new(current_user, targets).data }
+            options[type] = { issuable_metadata: Gitlab::IssuableMetadata.new(current_user, targets).data, include_subscribed: false }
           end
         end
       end

spec/requests/api/issues/get_project_issues_spec.rb

@@ -195,7 +195,6 @@ RSpec.describe API::Issues do
       milestone = create(:milestone, project: project)
       create(:issue, project: project, milestone: milestone, closed_by: create(:user))
 
-      create(:note_on_issue, project: project, noteable: issues[0])
       create(:note_on_issue, project: project, noteable: issues[0])
       create(:note_on_issue, project: project, noteable: issues[1])