From b40863f1a30a754f10531ecd119ab2795998cb45 Mon Sep 17 00:00:00 2001
From: Andrey Zhavoronkov <andrey.zhavoronkov@intel.com>
Date: Mon, 30 Nov 2020 14:40:34 +0300
Subject: [PATCH] updated changelog

---
 CHANGELOG.md              |  1 +
 cvat/apps/engine/views.py | 16 ++++++++--------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 987b5f11..82897f74 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -34,6 +34,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Reset zoom option doesn't work in tag annotation mode (<https://github.com/openvinotoolkit/cvat/pull/2443>)
 - Canvas is busy error (<https://github.com/openvinotoolkit/cvat/pull/2437>)
 - Projects view layout fix (<https://github.com/openvinotoolkit/cvat/pull/2503>)
+- Fixed the tasks view (infinite loading) when it is impossible to get a preview of the task (<https://github.com/openvinotoolkit/cvat/pull/2504>)
 
 ### Security
 
diff --git a/cvat/apps/engine/views.py b/cvat/apps/engine/views.py
index aec2f88a..e6d1745e 100644
--- a/cvat/apps/engine/views.py
+++ b/cvat/apps/engine/views.py
@@ -426,15 +426,15 @@ class TaskViewSet(auth.TaskGetQuerySetMixin, viewsets.ModelViewSet):
             possible_data_type_values = ('chunk', 'frame', 'preview')
             possible_quality_values = ('compressed', 'original')
 
-            if not data_type or data_type not in possible_data_type_values:
-                raise ValidationError(detail='Data type not specified or has wrong value')
-            elif data_type == 'chunk' or data_type == 'frame':
-                if not data_id:
-                    raise ValidationError(detail='Number not specified')
-                elif data_quality not in possible_quality_values:
-                    raise ValidationError(detail='Wrong quality value')
-
             try:
+                if not data_type or data_type not in possible_data_type_values:
+                    raise ValidationError(detail='Data type not specified or has wrong value')
+                elif data_type == 'chunk' or data_type == 'frame':
+                    if not data_id:
+                        raise ValidationError(detail='Number is not specified')
+                    elif data_quality not in possible_quality_values:
+                        raise ValidationError(detail='Wrong quality value')
+
                 db_task = self.get_object()
                 db_data = db_task.data
                 if not db_data: