[youtube] Handle incorrectly written cache files (#3549)

diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 3c9b0b58402189338b5480d1d20f589b751e6dfe..8b520e0f039cb62fbaa817de7938cab9e99dc63b 100644 (file)
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -374,6 +374,13 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
                 return lambda s: u''.join(s[i] for i in cache_spec)
             except IOError:
                 pass  # No cache available
+            except ValueError:
+                try:
+                    file_size = os.path.getsize(cache_fn)
+                except (OSError, IOError) as oe:
+                    file_size = str(oe)
+                self._downloader.report_warning(
+                    u'Cache %s failed (%s)' % (cache_fn, file_size))
 
         if player_type == 'js':
             code = self._download_webpage(