add client side validation for category minimum_required_tags

app/assets/javascripts/discourse/controllers/composer.js.es6

@@ -784,6 +784,14 @@ export default Ember.Controller.extend({
     }
   },
 
+  @computed('model.category', 'model.tags', 'lastValidatedAt')
+  tagValidation(category, tags, lastValidatedAt) {
+    const tagsArray = tags || [];
+    if (this.site.get('can_tag_topics') && category && category.get('minimum_required_tags') > tagsArray.length) {
+      return InputValidation.create({ failed: true, reason: I18n.t('composer.error.tags_missing', {count: category.get('minimum_required_tags')}), lastShownAt: lastValidatedAt });
+    }
+  },
+
   collapse() {
     this._saveDraft();
     this.set('model.composeState', Composer.DRAFT);

app/assets/javascripts/discourse/models/composer.js.es6

@@ -105,6 +105,11 @@ const Composer = RestModel.extend({
     return categoryId ? this.site.categories.findBy('id', categoryId) : null;
   },
 
+  @computed('category')
+  minimumRequiredTags(category) {
+    return (category && category.get('minimum_required_tags') > 0) ? category.get('minimum_required_tags') : null;
+  },
+
   creatingTopic: Em.computed.equal('action', CREATE_TOPIC),
   creatingSharedDraft: Em.computed.equal('action', CREATE_SHARED_DRAFT),
   creatingPrivateMessage: Em.computed.equal('action', PRIVATE_MESSAGE),
@@ -246,28 +251,41 @@ const Composer = RestModel.extend({
     return options;
   },
 
-  // whether to disable the post button
-  cantSubmitPost: function() {
+  @computed
+  isStaffUser() {
+    const currentUser = Discourse.User.current();
+    return currentUser && currentUser.get('staff');
+  },
+
+  @computed('loading', 'canEditTitle', 'titleLength', 'targetUsernames', 'replyLength', 'categoryId', 'missingReplyCharacters', 'tags', 'topicFirstPost', 'minimumRequiredTags', 'isStaffUser')
+  cantSubmitPost(loading, canEditTitle, titleLength, targetUsernames, replyLength, categoryId, missingReplyCharacters, tags, topicFirstPost, minimumRequiredTags, isStaffUser) {
 
     // can't submit while loading
-    if (this.get('loading')) return true;
+    if (loading) return true;
 
     // title is required when
     //  - creating a new topic/private message
     //  - editing the 1st post
-    if (this.get('canEditTitle') && !this.get('titleLengthValid')) return true;
+    if (canEditTitle && !this.get('titleLengthValid')) return true;
 
     // reply is always required
-    if (this.get('missingReplyCharacters') > 0) return true;
+    if (missingReplyCharacters > 0) return true;
+
+    if (this.site.get('can_tag_topics') && !isStaffUser && topicFirstPost && minimumRequiredTags) {
+      const tagsArray = tags || [];
+      if (tagsArray.length < minimumRequiredTags) {
+        return true;
+      }
+    }
 
     if (this.get("privateMessage")) {
       // need at least one user when sending a PM
-      return this.get('targetUsernames') && (this.get('targetUsernames').trim() + ',').indexOf(',') === 0;
+      return targetUsernames && (targetUsernames.trim() + ',').indexOf(',') === 0;
     } else {
       // has a category? (when needed)
       return this.get('requiredCategoryMissing');
     }
-  }.property('loading', 'canEditTitle', 'titleLength', 'targetUsernames', 'replyLength', 'categoryId', 'missingReplyCharacters'),
+  },
 
   @computed('canCategorize', 'categoryId')
   requiredCategoryMissing(canCategorize, categoryId) {

app/assets/javascripts/discourse/templates/composer.hbs

@@ -64,7 +64,8 @@
                   </div>
                 {{/if}}
                 {{#if canEditTags}}
-                  {{mini-tag-chooser tags=model.tags tabindex="4" categoryId=model.categoryId}}
+                  {{mini-tag-chooser tags=model.tags tabindex="4" categoryId=model.categoryId minimum=model.minimumRequiredTags}}
+                  {{popup-input-tip validation=tagValidation}}
                 {{/if}}
 
 

config/locales/client.en.yml

@@ -1303,6 +1303,7 @@ en:
         post_length: "Post must be at least {{min}} characters"
         try_like: 'Have you tried the <i class="fa fa-heart"></i> button?'
         category_missing: "You must choose a category"
+        tags_missing: "You must choose at least {{count}} tags"
 
       save_edit: "Save Edit"
       reply_original: "Reply on Original Topic"

lib/topic_creator.rb

@@ -155,7 +155,7 @@ class TopicCreator
 
   def setup_tags(topic)
     if @opts[:tags].blank?
-      unless @guardian.is_staff?
+      unless @guardian.is_staff? || !guardian.can_tag?(topic)
         # Validate minimum required tags for a category
         category = find_category
         if category.present? && category.minimum_required_tags > 0

spec/components/topic_creator_spec.rb

@@ -116,6 +116,13 @@ describe TopicCreator do
           expect(topic).to be_valid
           expect(topic.tags.length).to eq(2)
         end
+
+        it "lets new user create a topic if they don't have sufficient trust level to tag topics" do
+          SiteSetting.min_trust_level_to_tag_topics = 1
+          new_user = Fabricate(:newuser)
+          topic = TopicCreator.create(new_user, Guardian.new(new_user), valid_attrs.merge(category: "beta"))
+          expect(topic).to be_valid
+        end
       end
     end