Default to null user when asignee is unselected

Also implemented same behavior on the Issue Boards assignee block.
Fixed the default state for search/filter dropdown for issuables.

app/assets/javascripts/boards/components/board_sidebar.js

@@ -27,6 +27,9 @@ gl.issueBoards.BoardSidebar = Vue.extend({
   computed: {
     showSidebar () {
       return Object.keys(this.issue).length;
+    },
+    assigneeId() {
+      return this.issue.assignee ? this.issue.assignee.id : 0;
     }
   },
   watch: {

app/assets/javascripts/users_select.js

@@ -30,7 +30,7 @@
       $els.each((function(_this) {
         return function(i, dropdown) {
           var options = {};
-          var $block, $collapsedSidebar, $dropdown, $loading, $selectbox, $value, abilityName, assignTo, assigneeTemplate, collapsedAssigneeTemplate, defaultLabel, defaultNullUser, firstUser, issueURL, selectedId, showAnyUser, showNullUser, showMenuAbove;
+          var $block, $collapsedSidebar, $dropdown, $loading, $selectbox, $value, abilityName, assignTo, assigneeTemplate, collapsedAssigneeTemplate, defaultLabel, defaultNullUser, firstUser, issueURL, selectedId, selectedIdDefault, showAnyUser, showNullUser, showMenuAbove;
           $dropdown = $(dropdown);
           options.projectId = $dropdown.data('project-id');
           options.groupId = $dropdown.data('group-id');
@@ -51,8 +51,8 @@
           $value = $block.find('.value');
           $collapsedSidebar = $block.find('.sidebar-collapsed-user');
           $loading = $block.find('.block-loading').fadeOut();
-          selectedId = $dropdown.data('selected');
-          if (!selectedId) selectedId = (defaultNullUser && showNullUser) ? 0 : null;
+          selectedIdDefault = (defaultNullUser && showNullUser) ? 0 : null;
+          selectedId = $dropdown.data('selected') || selectedIdDefault;
           var updateIssueBoardsIssue = function () {
             $loading.removeClass('hidden').fadeIn();
@@ -188,12 +188,14 @@
             fieldName: $dropdown.data('field-name'),
             toggleLabel: function(selected, el) {
               if (selected && 'id' in selected && $(el).hasClass('is-active')) {
+                $dropdown.find('.dropdown-toggle-text').removeClass('is-default');
                 if (selected.text) {
                   return selected.text;
                 } else {
                   return selected.name;
                 }
               } else {
+                $dropdown.find('.dropdown-toggle-text').addClass('is-default');
                 return defaultLabel;
               }
             },
@@ -206,11 +208,12 @@
             },
             vue: $dropdown.hasClass('js-issue-board-sidebar'),
             clicked: function(user, $el, e) {
-              var isIssueIndex, isMRIndex, page, selected;
+              var isIssueIndex, isMRIndex, page, selected, isSelecting;
               page = $('body').data('page');
               isIssueIndex = page === 'projects:issues:index';
               isMRIndex = (page === page && page === 'projects:merge_requests:index');
-              selectedId = user.id;
+              isSelecting = (user.id !== selectedId);
+              selectedId = isSelecting ? user.id : selectedIdDefault;
               if ($dropdown.hasClass('js-filter-bulk-update') || $dropdown.hasClass('js-issuable-form-dropdown')) {
                 e.preventDefault();
                 if (selectedId === gon.current_user_id) {
@@ -227,7 +230,7 @@
               } else if ($dropdown.hasClass('js-filter-submit')) {
                 return $dropdown.closest('form').submit();
               } else if ($dropdown.hasClass('js-issue-board-sidebar')) {
-                if (user.id) {
+                if (user.id && isSelecting) {
                   gl.issueBoards.boardStoreIssueSet('assignee', new ListUser({
                     id: user.id,
                     username: user.username,
@@ -249,6 +252,9 @@
             },
             opened: function(e) {
               const $el = $(e.currentTarget);
+              if ($dropdown.hasClass('js-issue-board-sidebar')) {
+                selectedId = parseInt($dropdown[0].dataset.selected, 10) || selectedIdDefault;
+              }
               $el.find('.is-active').removeClass('is-active');
               $el.find(`li[data-user-id="${selectedId}"] .dropdown-menu-user-link`).addClass('is-active');
             },

app/views/projects/boards/components/sidebar/_assignee.html.haml

@@ -28,8 +28,9 @@
         ":value" => "issue.assignee.id",
         "v-if" => "issue.assignee" }
       .dropdown
-        %button.dropdown-menu-toggle.js-user-search.js-author-search.js-issue-board-sidebar{ type: "button", data: { toggle: "dropdown", field_name: "issue[assignee_id]", first_user: (current_user.username if current_user), current_user: "true", project_id: @project.id, null_user: "true" },
+        %button.dropdown-menu-toggle.js-user-search.js-author-search.js-issue-board-sidebar{ type: "button", data: { toggle: "dropdown", field_name: "issue[assignee_id]", first_user: (current_user.username if current_user), current_user: "true", project_id: @project.id, null_user: "true", null_user_default: "true" },
           ":data-issuable-id" => "issue.id",
+          ":data-selected" => "assigneeId",
           ":data-issue-update" => "'#{namespace_project_issues_path(@project.namespace, @project)}/' + issue.id + '.json'" }
           Select assignee
           = icon("chevron-down")

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

@@ -117,7 +117,7 @@
       .issues_bulk_update.hide
         = form_tag [:bulk_update, @project.namespace.becomes(Namespace), @project, type], method: :post, class: 'bulk-update'  do
           .filter-item.inline
-            = dropdown_tag("Status", options: { toggle_class: "js-issue-status", title: "Change status", dropdown_class: "dropdown-menu-status dropdown-menu-selectable", data: { field_name: "update[state_event]" } } ) do
+            = dropdown_tag("Status", options: { toggle_class: "js-issue-status", title: "Change status", dropdown_class: "dropdown-menu-status dropdown-menu-selectable", data: { field_name: "update[state_event]", default_label: "Status" } } ) do
               %ul
                 %li
                   %a{ href: "#", data: { id: "reopen" } } Open
@@ -125,13 +125,13 @@
                   %a{ href: "#", data: { id: "close" } } Closed
           .filter-item.inline
             = dropdown_tag("Assignee", options: { toggle_class: "js-user-search js-update-assignee js-filter-submit js-filter-bulk-update", title: "Assign to", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable",
-              placeholder: "Search authors", data: { first_user: (current_user.username if current_user), null_user: true, current_user: true, project_id: @project.id, field_name: "update[assignee_id]" } })
+              placeholder: "Search authors", data: { first_user: (current_user.username if current_user), null_user: true, current_user: true, project_id: @project.id, field_name: "update[assignee_id]", default_label: "Assignee" } })
           .filter-item.inline
-            = dropdown_tag("Milestone", options: { title: "Assign milestone", toggle_class: 'js-milestone-select js-extra-options js-filter-submit js-filter-bulk-update', filter: true, dropdown_class: "dropdown-menu-selectable dropdown-menu-milestone", placeholder: "Search milestones", data: { show_no: true, field_name: "update[milestone_id]", project_id: @project.id, milestones: namespace_project_milestones_path(@project.namespace, @project, :json), use_id: true } })
+            = dropdown_tag("Milestone", options: { title: "Assign milestone", toggle_class: 'js-milestone-select js-extra-options js-filter-submit js-filter-bulk-update', filter: true, dropdown_class: "dropdown-menu-selectable dropdown-menu-milestone", placeholder: "Search milestones", data: { show_no: true, field_name: "update[milestone_id]", project_id: @project.id, milestones: namespace_project_milestones_path(@project.namespace, @project, :json), use_id: true, default_label: "Milestone" } })
           .filter-item.inline.labels-filter
-            = render "shared/issuable/label_dropdown", classes: ['js-filter-bulk-update', 'js-multiselect'], dropdown_title: 'Apply a label', show_create: false, show_footer: false, extra_options: false, filter_submit: false, data_options: { persist_when_hide: "true", field_name: "update[label_ids][]", show_no: false, show_any: false, use_id: true }
+            = render "shared/issuable/label_dropdown", classes: ['js-filter-bulk-update', 'js-multiselect'], dropdown_title: 'Apply a label', show_create: false, show_footer: false, extra_options: false, filter_submit: false, data_options: { persist_when_hide: "true", field_name: "update[label_ids][]", show_no: false, show_any: false, use_id: true, default_label: "Labels" }
           .filter-item.inline
-            = dropdown_tag("Subscription", options: { toggle_class: "js-subscription-event", title: "Change subscription", dropdown_class: "dropdown-menu-selectable", data: { field_name: "update[subscription_event]" } } ) do
+            = dropdown_tag("Subscription", options: { toggle_class: "js-subscription-event", title: "Change subscription", dropdown_class: "dropdown-menu-selectable", data: { field_name: "update[subscription_event]", default_label: "Subscription" } } ) do
               %ul
                 %li
                   %a{ href: "#", data: { id: "subscribe" } } Subscribe