FIX: improves UI state when no extensions are allowed for upload

app/assets/javascripts/discourse/components/composer-editor.js.es6

@@ -13,6 +13,8 @@ import { tinyAvatar,
          displayErrorForUpload,
          getUploadMarkdown,
          validateUploadedFiles,
+         authorizesOneOrMoreExtensions,
+         authorizesOneOrMoreImageExtensions,
          formatUsername,
          clipboardData
 } from 'discourse/lib/utilities';
@@ -36,6 +38,12 @@ export default Ember.Component.extend({
     return `[${I18n.t('uploading')}]() `;
   },
 
+  @computed()
+  replyPlaceholder() {
+    const key = authorizesOneOrMoreImageExtensions() ? "reply_placeholder" : "reply_placeholder_no_images";
+    return `composer.${key}`;
+  },
+
   @observes('composer.uploadCancelled')
   _cancelUpload() {
     if (!this.get('composer.uploadCancelled')) { return; }
@@ -662,13 +670,15 @@ export default Ember.Component.extend({
         unshift: true
       });
 
-      toolbar.addButton({
-        id: 'upload',
-        group: 'insertions',
-        icon: 'upload',
-        title: 'upload',
-        sendAction: 'showUploadModal'
-      });
+      if (authorizesOneOrMoreExtensions()) {
+        toolbar.addButton({
+          id: 'upload',
+          group: 'insertions',
+          icon: 'upload',
+          title: 'upload',
+          sendAction: 'showUploadModal'
+        });
+      }
 
       toolbar.addButton({
         id: 'options',

app/assets/javascripts/discourse/lib/utilities.js.es6

@@ -193,6 +193,8 @@ export function validateUploadedFiles(files, opts) {
 }
 
 export function validateUploadedFile(file, opts) {
+  if (!authorizesOneOrMoreExtensions()) return false;
+
   opts = opts || {};
 
   const name = file && file.name;
@@ -277,6 +279,21 @@ export function authorizesAllExtensions() {
   return Discourse.SiteSettings.authorized_extensions.indexOf("*") >= 0;
 }
 
+export function authorizesOneOrMoreExtensions() {
+  if (authorizesAllExtensions()) return true;
+
+  return Discourse.SiteSettings.authorized_extensions
+          .split("|")
+          .filter(ext => ext)
+          .length > 0;
+}
+
+export function authorizesOneOrMoreImageExtensions() {
+  if (authorizesAllExtensions()) return true;
+
+  return imagesExtensions().length > 0;
+}
+
 export function isAnImage(path) {
   return (/\.(png|jpe?g|gif|bmp|tiff?|svg|webp|ico)$/i).test(path);
 }

app/assets/javascripts/discourse/templates/components/composer-editor.hbs

@@ -1,7 +1,7 @@
 {{d-editor
   tabindex="4"
   value=composer.reply
-  placeholder="composer.reply_placeholder"
+  placeholder=replyPlaceholder
   previewUpdated="previewUpdated"
   markdownOptions=markdownOptions
   extraButtons="extraButtons"