Add hint about missing media attachment description in web UI (#17845)

app/javascript/mastodon/features/compose/components/upload.js

@@ -5,7 +5,6 @@ import Motion from '../../ui/util/optional_motion';
 import spring from 'react-motion/lib/spring';
 import ImmutablePureComponent from 'react-immutable-pure-component';
 import { FormattedMessage } from 'react-intl';
-import classNames from 'classnames';
 import Icon from 'mastodon/components/icon';
 
 export default class Upload extends ImmutablePureComponent {
@@ -43,10 +42,16 @@ export default class Upload extends ImmutablePureComponent {
         <Motion defaultStyle={{ scale: 0.8 }} style={{ scale: spring(1, { stiffness: 180, damping: 12 }) }}>
           {({ scale }) => (
             <div className='compose-form__upload-thumbnail' style={{ transform: `scale(${scale})`, backgroundImage: `url(${media.get('preview_url')})`, backgroundPosition: `${x}% ${y}%` }}>
-              <div className={classNames('compose-form__upload__actions', { active: true })}>
+              <div className='compose-form__upload__actions'>
                 <button className='icon-button' onClick={this.handleUndoClick}><Icon id='times' /> <FormattedMessage id='upload_form.undo' defaultMessage='Delete' /></button>
                 {!isEditingStatus && (<button className='icon-button' onClick={this.handleFocalPointClick}><Icon id='pencil' /> <FormattedMessage id='upload_form.edit' defaultMessage='Edit' /></button>)}
               </div>
+
+              {(media.get('description') || '').length === 0 && (
+                <div className='compose-form__upload__warning'>
+                  <button className='icon-button' onClick={this.handleFocalPointClick}><Icon id='info-circle' /> <FormattedMessage id='upload_form.description_missing' defaultMessage='No description added' /></button>
+                </div>
+              )}
             </div>
           )}
         </Motion>

app/javascript/styles/mastodon/components.scss

@@ -596,8 +596,7 @@
         display: flex;
         align-items: flex-start;
         justify-content: space-between;
-        opacity: 0;
-        transition: opacity .1s ease;
+      }
 
       .icon-button {
         flex: 0 1 auto;
@@ -614,12 +613,7 @@
         }
       }
 
-        &.active {
-          opacity: 1;
-        }
-      }
-
-      &-description {
+      &__warning {
         position: absolute;
         z-index: 2;
         bottom: 0;
@@ -627,34 +621,6 @@
         right: 0;
         box-sizing: border-box;
         background: linear-gradient(0deg, rgba($base-shadow-color, 0.8) 0, rgba($base-shadow-color, 0.35) 80%, transparent);
-        padding: 10px;
-        opacity: 0;
-        transition: opacity .1s ease;
-
-        textarea {
-          background: transparent;
-          color: $secondary-text-color;
-          border: 0;
-          padding: 0;
-          margin: 0;
-          width: 100%;
-          font-family: inherit;
-          font-size: 14px;
-          font-weight: 500;
-
-          &:focus {
-            color: $white;
-          }
-
-          &::placeholder {
-            opacity: 0.75;
-            color: $secondary-text-color;
-          }
-        }
-
-        &.active {
-          opacity: 1;
-        }
       }
     }