DEV: Upgrade our widget handlebars compiler

Now supports subexpressions such as i18n and concat, plus automatic
attaching of widgets similar to ember.

app/assets/javascripts/discourse/lib/transform-post.js.es6

@@ -222,7 +222,7 @@ export default function transformPost(
           acted,
           count,
           canUndo: a.can_undo,
-          canDeferFlags: a.can_defer_flags,
+          canIgnoreFlags: a.can_defer_flags,
           description: actionDescription(action, acted, count)
         };
       });

app/assets/javascripts/discourse/widgets/actions-summary.js.es6

@@ -63,15 +63,12 @@ createWidget("small-user-list", {
 
 createWidget("action-link", {
   tagName: "span.action-link",
+  template: hbs`<a>{{attrs.text}}. </a>`,
 
   buildClasses(attrs) {
     return attrs.className;
   },
 
-  html(attrs) {
-    return h("a", [attrs.text, ". "]);
-  },
-
   click() {
     this.sendWidgetAction(this.attrs.action);
   }
@@ -82,56 +79,24 @@ createWidget("actions-summary-item", {
   buildKey: attrs => `actions-summary-item-${attrs.id}`,
 
   defaultState() {
-    return { users: [] };
+    return { users: null };
   },
 
-  html(attrs, state) {
-    const users = state.users;
+  template: hbs`
+    {{#if state.users}}
+      {{small-user-list users=state.users description=(concat "post.actions.people." attrs.action)}}
+    {{else}}
+      {{action-link action="whoActed" text=attrs.description}}
+    {{/if}}
 
-    const result = [];
-    const action = attrs.action;
+    {{#if attrs.canUndo}}
+      {{action-link action="undo" className="undo" text=(i18n (concat "post.actions.undo." attrs.action))}}
+    {{/if}}
 
-    if (users.length === 0) {
-      result.push(
-        this.attach("action-link", {
-          action: "whoActed",
-          text: attrs.description
-        })
-      );
-    } else {
-      result.push(
-        this.attach("small-user-list", {
-          users,
-          description: `post.actions.people.${action}`
-        })
-      );
-    }
-
-    if (attrs.canUndo) {
-      result.push(
-        this.attach("action-link", {
-          action: "undo",
-          className: "undo",
-          text: I18n.t(`post.actions.undo.${action}`)
-        })
-      );
-    }
-
-    if (attrs.canDeferFlags) {
-      const flagsDesc = I18n.t(`post.actions.defer_flags`, {
-        count: attrs.count
-      });
-      result.push(
-        this.attach("action-link", {
-          action: "deferFlags",
-          className: "defer-flags",
-          text: flagsDesc
-        })
-      );
-    }
-
-    return result;
-  },
+    {{#if attrs.canIgnoreFlags}}
+      {{action-link action="deferFlags" className="defer-flags" text=(i18n "post.actions.defer_flags" count=attrs.count)}}
+    {{/if}}
+  `,
 
   whoActed() {
     const attrs = this.attrs;
@@ -159,7 +124,7 @@ export default createWidget("actions-summary", {
   tagName: "section.post-actions",
   template: hbs`
     {{#each attrs.actionsSummary as |as|}}
-      {{attach widget="actions-summary-item" attrs=as}}
+      {{actions-summary-item attrs=as}}
       <div class='clearfix'></div>
     {{/each}}
     {{#if attrs.deleted_at}}

app/assets/javascripts/discourse/widgets/header-contents.js.es6

@@ -4,9 +4,9 @@ import hbs from "discourse/widgets/hbs-compiler";
 createWidget("header-contents", {
   tagName: "div.contents.clearfix",
   template: hbs`
-    {{attach widget="home-logo" attrs=attrs}}
+    {{home-logo attrs=attrs}}
     {{#if attrs.topic}}
-      {{attach widget="header-topic-info" attrs=attrs}}
+      {{header-topic-info attrs=attrs}}
     {{/if}}
     <div class="panel clearfix">{{yield}}</div>
   `

app/assets/javascripts/discourse/widgets/private-message-map.js.es6

@@ -34,9 +34,9 @@ createWidget("pm-map-user-group", {
       <span class="group-name">{{attrs.group.name}}</span>
     </a>
     {{#if attrs.isEditing}}
-    {{#if attrs.canRemoveAllowedUsers}}
-      {{attach widget="pm-remove-group-link" attrs=attrs.group}}
-    {{/if}}
+      {{#if attrs.canRemoveAllowedUsers}}
+        {{pm-remove-group-link attrs=attrs.group}}
+      {{/if}}
     {{/if}}
   `
 });

app/assets/javascripts/discourse/widgets/user-menu.js.es6

@@ -109,15 +109,12 @@ createWidget("user-menu-dismiss-link", {
   template: hbs`
     <ul class='menu-links'>
       <li>
-        {{attach
-          widget="link"
-          attrs=(hash
-            action="dismissNotifications"
-            className="dismiss"
-            tabindex="0"
-            icon="check"
-            label="user.dismiss"
-            title="user.dismiss_notifications_tooltip")}}
+        {{link action="dismissNotifications"
+          className="dismiss"
+          tabindex="0"
+          icon="check"
+          label="user.dismiss"
+          title="user.dismiss_notifications_tooltip"}}
       </li>
     </ul>
   `