[downloader/external] Fix download finalization when writing file to stdout (closes #10809)

An OSError or IOError generally indicates something a little more
wrong than a "simple" UnavailableVideoError, so print the actual
traceback that leads to the exception. Otherwise meaningful postmortem
debugging a bug report is essentially infeasible.

1 files changed, 15 insertions, 9 deletions

diff --git a/youtube_dl/downloader/external.py b/youtube_dl/downloader/external.py
index db018fa89..48c255ddc 100644
--- a/youtube_dl/downloader/external.py
+++ b/youtube_dl/downloader/external.py
@@ -41,15 +41,21 @@ class ExternalFD(FileDownloader):
             self.to_screen('[%s] Interrupted by user' % self.get_basename())
 
         if retval == 0:
-            fsize = os.path.getsize(encodeFilename(tmpfilename))
-            self.to_screen('\r[%s] Downloaded %s bytes' % (self.get_basename(), fsize))
-            self.try_rename(tmpfilename, filename)
-            self._hook_progress({
-                'downloaded_bytes': fsize,
-                'total_bytes': fsize,
-                'filename': filename,
-                'status': 'finished',
-            })
+            if filename == '-':
+                self._hook_progress({
+                    'filename': filename,
+                    'status': 'finished',
+                })
+            else:
+                fsize = os.path.getsize(encodeFilename(tmpfilename))
+                self.to_screen('\r[%s] Downloaded %s bytes' % (self.get_basename(), fsize))
+                self.try_rename(tmpfilename, filename)
+                self._hook_progress({
+                    'downloaded_bytes': fsize,
+                    'total_bytes': fsize,
+                    'filename': filename,
+                    'status': 'finished',
+                })
             return True
         else:
             self.to_stderr('\n')