Remove prev/next buttons on issues and merge requests

The buttons were rarely used and added at least 1 query each on every page load.

CHANGELOG

@@ -45,6 +45,7 @@ v 8.8.4 (unreleased)
   - Fix todos page throwing errors when you have a project pending deletion
   - Reduce number of SQL queries when rendering user references
   - Upgrade to jQuery 2
+  - Remove prev/next buttons on issues and merge requests
 
 v 8.8.3
   - Fix 404 page when viewing TODOs that contain milestones or labels in different projects. !4312

app/assets/javascripts/shortcuts_issuable.coffee

@@ -10,14 +10,6 @@ class @ShortcutsIssuable extends ShortcutsNavigation
       @replyWithSelectedText()
       return false
     )
-    Mousetrap.bind('j', =>
-      @prevIssue()
-      return false
-    )
-    Mousetrap.bind('k', =>
-      @nextIssue()
-      return false
-    )
     Mousetrap.bind('e', =>
       @editIssue()
       return false
@@ -29,16 +21,6 @@ class @ShortcutsIssuable extends ShortcutsNavigation
     else
       @enabledHelp.push('.hidden-shortcut.issues')
 
-  prevIssue: ->
-    $prevBtn = $('.prev-btn')
-    if not $prevBtn.hasClass('disabled')
-      Turbolinks.visit($prevBtn.attr('href'))
-
-  nextIssue: ->
-    $nextBtn = $('.next-btn')
-    if not $nextBtn.hasClass('disabled')
-      Turbolinks.visit($nextBtn.attr('href'))
-
   replyWithSelectedText: ->
     if window.getSelection
       selected = window.getSelection().toString()

app/helpers/issuables_helper.rb

@@ -8,14 +8,6 @@ module IssuablesHelper
     "right-sidebar-#{sidebar_gutter_collapsed? ? 'collapsed' : 'expanded'}"
   end
 
-  def issuables_count(issuable)
-    base_issuable_scope(issuable).maximum(:iid)
-  end
-
-  def next_issuable_for(issuable)
-    base_issuable_scope(issuable).where('iid > ?', issuable.iid).last
-  end
-
   def multi_label_name(current_labels, default_label)
     # current_labels may be a string from before
     if current_labels.is_a?(Array)
@@ -45,10 +37,6 @@ module IssuablesHelper
     end
   end
 
-  def prev_issuable_for(issuable)
-    base_issuable_scope(issuable).where('iid < ?', issuable.iid).first
-  end
-
   def user_dropdown_label(user_id, default_label)
     return default_label if user_id.nil?
     return "Unassigned" if user_id == "0"

app/views/shared/issuable/_sidebar.html.haml

@@ -2,23 +2,8 @@
   .issuable-sidebar
     - can_edit_issuable = can?(current_user, :"admin_#{issuable.to_ability_name}", @project)
     .block.issuable-sidebar-header
-      %span.issuable-count.hide-collapsed.pull-left
-        = issuable.iid
-        of
-        = issuables_count(issuable)
       %a.gutter-toggle.pull-right.js-sidebar-toggle{href: '#'}
         = sidebar_gutter_toggle_icon
-      .issuable-nav.hide-collapsed.pull-right.btn-group{role: 'group', "aria-label" => '...'}
-        - if prev_issuable = prev_issuable_for(issuable)
-          = link_to 'Prev', [@project.namespace.becomes(Namespace), @project, prev_issuable], class: 'btn btn-default prev-btn issuable-pager'
-        - else
-          %a.btn.btn-default.issuable-pager.disabled{href: '#'}
-            Prev
-        - if next_issuable = next_issuable_for(issuable)
-          = link_to 'Next', [@project.namespace.becomes(Namespace), @project, next_issuable], class: 'btn btn-default next-btn issuable-pager'
-        - else
-          %a.btn.btn-default.issuable-pager.disabled{href: '#'}
-            Next
 
     = form_for [@project.namespace.becomes(Namespace), @project, issuable], remote: true, format: :json, html: {class: 'issuable-context-form inline-update js-issuable-update'} do |f|
       .block.assignee

features/project/issues/issues.feature

@@ -25,13 +25,6 @@ Feature: Project Issues
   Scenario: I visit issue page
     Given I click link "Release 0.4"
     Then I should see issue "Release 0.4"
-    And I should see "1 of 2" in the sidebar
-
-  Scenario: I navigate between issues
-    Given I click link "Release 0.4"
-    Then I click link "Next" in the sidebar
-    Then I should see issue "Tweet control"
-    And I should see "2 of 2" in the sidebar
 
   @javascript
   Scenario: I filter by author

features/project/merge_requests.feature

@@ -49,14 +49,12 @@ Feature: Project Merge Requests
   Scenario: I visit an open merge request page
     Given I click link "Bug NS-04"
     Then I should see merge request "Bug NS-04"
-    And I should see "1 of 1" in the sidebar
 
   Scenario: I visit a merged merge request page
     Given project "Shop" have "Feature NS-05" merged merge request
     And I click link "Merged"
     And I click link "Feature NS-05"
     Then I should see merge request "Feature NS-05"
-    And I should see "3 of 3" in the sidebar
 
   Scenario: I close merge request page
     Given I click link "Bug NS-04"

features/steps/shared/issuable.rb

@@ -138,22 +138,6 @@ module SharedIssuable
     end
   end
 
-  step 'I should see "1 of 1" in the sidebar' do
-    expect_sidebar_content('1 of 1')
-  end
-
-  step 'I should see "1 of 2" in the sidebar' do
-    expect_sidebar_content('1 of 2')
-  end
-
-  step 'I should see "2 of 2" in the sidebar' do
-    expect_sidebar_content('2 of 2')
-  end
-
-  step 'I should see "3 of 3" in the sidebar' do
-    expect_sidebar_content('3 of 3')
-  end
-
   step 'I click link "Next" in the sidebar' do
     page.within '.issuable-sidebar' do
       click_link 'Next'