Flush bz2 data even if nothing had been written so far. Fixes #1013882

Lib/tarfile.py

@@ -350,9 +350,9 @@ class _Stream:
         if self.closed:
             return
 
+        if self.mode == "w" and self.type != "tar":
+            self.buf += self.cmp.flush()
         if self.mode == "w" and self.buf:
-            if self.type != "tar":
-                self.buf += self.cmp.flush()
             self.fileobj.write(self.buf)
             self.buf = ""
             if self.type == "gz":

Misc/NEWS

@@ -49,6 +49,8 @@ Extension modules
 Library
 -------
 
+- Bug #1013882: Flush bz2 data even if nothing had been written so far.
+
 - Patch #997284: Allow pydoc to work with XP Themes (.manifest file)
 
 - Patch #808719: Ignore locale's encoding in IDLE if it is an empty string.