From 8758221e7344645bc1357578ec1789aa7d46da08 Mon Sep 17 00:00:00 2001
From: Daniel Sockwell <dsockwell@gmail.com>
Date: Fri, 20 Mar 2020 22:10:42 -0400
Subject: [PATCH] Fix frontend crash when deleting announcements (#13283)
This two-line change fixes a crash in the front end that occurred
under the following circumstances:
* A server had more than one announcement,
* A user was displaying the announcements, and
* An announcement was deleted (or unpublished, which amounts to
the same thing.)
As might be expected, the bug was caused by attempting to access a
notification using an index value outside the bounds of the existing
announcements. Specifically, in two places. First,
`_markAnnouncementAsRead` attempts to modify announcements based on
the current index. This is what caused the front end crash. Second,
when rendering the `Announcements` component, the code paginates the
announcements and displays the current one. This did not cause a
crash, but caused the front end to confusingly display a blank
announcement (in situations that would have caused a crash) with no
way for the user to navigate back to previous announcements.
This commit fixes both issues by adding a check to ensure that the
code never attempts to access an announcement with an index greater
than or equal to the number of announcements present.
---
.../features/getting_started/components/announcements.js | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/app/javascript/mastodon/features/getting_started/components/announcements.js b/app/javascript/mastodon/features/getting_started/components/announcements.js
index fb4a6bf0d..ec57c41b2 100644
--- a/app/javascript/mastodon/features/getting_started/components/announcements.js
+++ b/app/javascript/mastodon/features/getting_started/components/announcements.js
@@ -389,7 +389,7 @@ class Announcements extends ImmutablePureComponent {
_markAnnouncementAsRead () {
const { dismissAnnouncement, announcements } = this.props;
const { index } = this.state;
- const announcement = announcements.get(index);
+ const announcement = announcements.get(index) || announcements.get(index - 1);
if (!announcement.get('read')) dismissAnnouncement(announcement.get('id'));
}
@@ -407,7 +407,7 @@ class Announcements extends ImmutablePureComponent {
render () {
const { announcements, intl } = this.props;
- const { index } = this.state;
+ const index = this.state.index < announcements.size ? this.state.index : announcements.size - 1;
if (announcements.isEmpty()) {
return null;