[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.

youtube_dl/downloader/common.py

@@ -249,12 +249,14 @@ class FileDownloader(object):
             if self.params.get('noprogress', False):
                 self.to_screen('[download] Download completed')
             else:
-                s['_total_bytes_str'] = format_bytes(s['total_bytes'])
+                if s.get('total_bytes') is not None:
+                    s['_total_bytes_str'] = format_bytes(s['total_bytes'])
+                    msg_template = '100%% of %(_total_bytes_str)s'
+                else:
+                    msg_template = 'Completed'
                 if s.get('elapsed') is not None:
                     s['_elapsed_str'] = self.format_seconds(s['elapsed'])
-                    msg_template = '100%% of %(_total_bytes_str)s in %(_elapsed_str)s'
-                else:
-                    msg_template = '100%% of %(_total_bytes_str)s'
+                    msg_template += ' in %(_elapsed_str)s'
                 self._report_progress_status(
                     msg_template % s, is_last_line=True)
 

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')