Add tooltip for milestone due date to issue and merge request lists

app/helpers/milestones_helper.rb

@@ -94,6 +94,12 @@ module MilestonesHelper
     end
   end
+  def milestone_tooltip_title(milestone)
+    if milestone.due_date
+      [milestone.due_date.to_s(:medium), "(#{milestone_remaining_days(milestone)})"].join(' ')
+    end
+  end
+
   def milestone_remaining_days(milestone)
     if milestone.expired?
       content_tag(:strong, 'Past due')

app/views/projects/issues/_issue.html.haml

@@ -24,7 +24,7 @@
           - if issue.milestone
             %span.issuable-milestone.hidden-xs
                
-              = link_to project_issues_path(issue.project, milestone_title: issue.milestone.title) do
+              = link_to project_issues_path(issue.project, milestone_title: issue.milestone.title), data: { html: 1, toggle: 'tooltip', title: milestone_tooltip_title(issue.milestone) } do
                 = icon('clock-o')
                 = issue.milestone.title
           - if issue.due_date

app/views/projects/merge_requests/_merge_request.html.haml

@@ -23,7 +23,7 @@
         - if merge_request.milestone
           %span.issuable-milestone.hidden-xs
              
-            = link_to project_merge_requests_path(merge_request.project, milestone_title: merge_request.milestone.title) do
+            = link_to project_merge_requests_path(merge_request.project, milestone_title: merge_request.milestone.title), data: { html: 1, toggle: 'tooltip', title: milestone_tooltip_title(merge_request.milestone) } do
               = icon('clock-o')
               = merge_request.milestone.title
         - if merge_request.target_project.default_branch != merge_request.target_branch

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

@@ -26,7 +26,7 @@
           = icon('clock-o', 'aria-hidden': 'true')
           %span.milestone-title
             - if issuable.milestone
-              %span.has-tooltip{ title: "#{issuable.milestone.title}<br>#{milestone_remaining_days(issuable.milestone)}", data: { container: 'body', html: 1, placement: 'left' } }
+              %span.has-tooltip{ title: "#{issuable.milestone.title}<br>#{milestone_tooltip_title(issuable.milestone)}", data: { container: 'body', html: 1, placement: 'left' } }
                 = issuable.milestone.title
             - else
               None
@@ -37,7 +37,7 @@
             = link_to 'Edit', '#', class: 'js-sidebar-dropdown-toggle edit-link pull-right'
         .value.hide-collapsed
           - if issuable.milestone
-            = link_to issuable.milestone.title, milestone_path(issuable.milestone), class: "bold has-tooltip", title: milestone_remaining_days(issuable.milestone), data: { container: "body", html: 1 }
+            = link_to issuable.milestone.title, milestone_path(issuable.milestone), class: "bold has-tooltip", title: milestone_tooltip_title(issuable.milestone), data: { container: "body", html: 1 }
           - else
             %span.no-value None

changelogs/unreleased/add_tooltip_for_milestone_in_issues_list.yml

+---
+title: Add tooltip for milestone due date to issue and merge request lists
+merge_request: 14318
+author: Vitaliy @blackst0ne Klachkov
+type: added