No empty comments

admin/schema_changes/13.sql

@@ -0,0 +1,8 @@
+BEGIN;
+
+ALTER TABLE "comment_revision"
+  ALTER COLUMN text
+  SET NOT NULL,
+  ADD CHECK (text <> '');
+
+COMMIT;

admin/sql/create_tables.sql

@@ -13,7 +13,7 @@ CREATE TABLE comment_revision (
     id          SERIAL      NOT NULL,
     comment_id  UUID        NOT NULL,
     "timestamp" TIMESTAMP   NOT NULL DEFAULT NOW(),
-    text        VARCHAR
+    text        VARCHAR     NOT NULL CHECK (text <> '')
 );
 
 CREATE TABLE license (

critiquebrainz/frontend/forms/comment.py

@@ -2,11 +2,12 @@
 from flask_wtf import Form
 from wtforms import TextAreaField, StringField
 from wtforms.widgets import HiddenInput
+from wtforms.validators import DataRequired
 
 
 class CommentEditForm(Form):
     state = StringField(widget=HiddenInput(), default='publish')
-    text = TextAreaField(lazy_gettext("Add a comment..."))
+    text = TextAreaField(lazy_gettext("Add a comment..."), validators=[DataRequired()])
     review_id = StringField(widget=HiddenInput())
 
     def __init__(self, review_id=None, **kwargs):

critiquebrainz/frontend/views/comment.py

@@ -31,10 +31,12 @@
 def create():
     form = CommentEditForm()
     if form.validate_on_submit():
-        comment = db_comment.create(
+        db_comment.create(
             review_id=form.review_id.data,
             user_id=current_user.id,
             text=form.text.data,
         )
         flash.success('Comment has been saved!')
-    return redirect(url_for('review.entity', id=comment['review_id']))
+    else:
+        flash.error('Comment must not be empty!')
+    return redirect(url_for('review.entity', id=form.review_id.data))