7 files changed, 18 insertions, 4 deletions
diff --git a/app/controllers/api/v1/statuses_controller.rb b/app/controllers/api/v1/statuses_controller.rb
index 2f55e95fd..93a253cbb 100644
--- a/app/controllers/api/v1/statuses_controller.rb
+++ b/app/controllers/api/v1/statuses_controller.rb
@@ -7,6 +7,7 @@ class Api::V1::StatusesController < Api::BaseController
   before_action -> { doorkeeper_authorize! :write, :'write:statuses' }, only:   [:create, :destroy]
   before_action :require_user!, except:  [:show, :context]
   before_action :set_status, only:       [:show, :context]
+  before_action :set_thread, only:       [:create]
 
   override_rate_limit_headers :create, family: :statuses
 
@@ -36,7 +37,7 @@ class Api::V1::StatusesController < Api::BaseController
   def create
     @status = PostStatusService.new.call(current_user.account,
                                          text: status_params[:status],
-                                         thread: status_params[:in_reply_to_id].blank? ? nil : Status.find(status_params[:in_reply_to_id]),
+                                         thread: @thread,
                                          media_ids: status_params[:media_ids],
                                          sensitive: status_params[:sensitive],
                                          spoiler_text: status_params[:spoiler_text],
@@ -69,6 +70,12 @@ class Api::V1::StatusesController < Api::BaseController
     raise ActiveRecord::RecordNotFound
   end
 
+  def set_thread
+    @thread = status_params[:in_reply_to_id].blank? ? nil : Status.find(status_params[:in_reply_to_id])
+  rescue ActiveRecord::RecordNotFound
+    render json: { error: I18n.t('statuses.errors.in_reply_not_found') }, status: 404
+  end
+
   def status_params
     params.permit(
       :status,
diff --git a/app/javascript/mastodon/actions/accounts.js b/app/javascript/mastodon/actions/accounts.js
index 4af36e998..cb2c682a4 100644
--- a/app/javascript/mastodon/actions/accounts.js
+++ b/app/javascript/mastodon/actions/accounts.js
@@ -396,6 +396,7 @@ export function fetchFollowersFail(id, error) {
     type: FOLLOWERS_FETCH_FAIL,
     id,
     error,
+    skipNotFound: true,
   };
 };
 
@@ -482,6 +483,7 @@ export function fetchFollowingFail(id, error) {
     type: FOLLOWING_FETCH_FAIL,
     id,
     error,
+    skipNotFound: true,
   };
 };
 
@@ -571,6 +573,7 @@ export function fetchRelationshipsFail(error) {
     type: RELATIONSHIPS_FETCH_FAIL,
     error,
     skipLoading: true,
+    skipNotFound: true,
   };
 };
 
diff --git a/app/javascript/mastodon/actions/alerts.js b/app/javascript/mastodon/actions/alerts.js
index cd36d8007..1670f9c10 100644
--- a/app/javascript/mastodon/actions/alerts.js
+++ b/app/javascript/mastodon/actions/alerts.js
@@ -34,11 +34,11 @@ export function showAlert(title = messages.unexpectedTitle, message = messages.u
   };
 };
 
-export function showAlertForError(error) {
+export function showAlertForError(error, skipNotFound = false) {
   if (error.response) {
     const { data, status, statusText, headers } = error.response;
 
-    if (status === 404 || status === 410) {
+    if (skipNotFound && (status === 404 || status === 410)) {
       // Skip these errors as they are reflected in the UI
       return { type: ALERT_NOOP };
     }
diff --git a/app/javascript/mastodon/actions/identity_proofs.js b/app/javascript/mastodon/actions/identity_proofs.js
index 449debf61..103983956 100644
--- a/app/javascript/mastodon/actions/identity_proofs.js
+++ b/app/javascript/mastodon/actions/identity_proofs.js
@@ -27,4 +27,5 @@ export const fetchAccountIdentityProofsFail = (accountId, err) => ({
   type: IDENTITY_PROOFS_ACCOUNT_FETCH_FAIL,
   accountId,
   err,
+  skipNotFound: true,
 });
diff --git a/app/javascript/mastodon/actions/timelines.js b/app/javascript/mastodon/actions/timelines.js
index 054668655..cdd2111f8 100644
--- a/app/javascript/mastodon/actions/timelines.js
+++ b/app/javascript/mastodon/actions/timelines.js
@@ -149,6 +149,7 @@ export function expandTimelineFail(timeline, error, isLoadingMore) {
     timeline,
     error,
     skipLoading: !isLoadingMore,
+    skipNotFound: timeline.startsWith('account:'),
   };
 };
 
diff --git a/app/javascript/mastodon/middleware/errors.js b/app/javascript/mastodon/middleware/errors.js
index 3cebb42e0..0a65fd321 100644
--- a/app/javascript/mastodon/middleware/errors.js
+++ b/app/javascript/mastodon/middleware/errors.js
@@ -8,7 +8,7 @@ export default function errorsMiddleware() {
       const isFail = new RegExp(`${defaultFailSuffix}$`, 'g');
 
       if (action.type.match(isFail)) {
-        dispatch(showAlertForError(action.error));
+        dispatch(showAlertForError(action.error, action.skipNotFound));
       }
     }
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 13f22d922..ef21fa54a 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1078,6 +1078,8 @@ en:
     disallowed_hashtags:
       one: 'contained a disallowed hashtag: %{tags}'
       other: 'contained the disallowed hashtags: %{tags}'
+    errors:
+      in_reply_not_found: The status you are trying to reply to does not appear to exist.
     language_detection: Automatically detect language
     open_in_web: Open in web
     over_character_limit: character limit of %{max} exceeded