#12448: smtplib now flushes stdout while running ``python -m smtplib``

in order to display the prompt correctly.  Patch by Petri Lehtinen.

Lib/smtplib.py

@@ -912,6 +912,7 @@ if __name__ == '__main__':
 
     def prompt(prompt):
         sys.stdout.write(prompt + ": ")
+        sys.stdout.flush()
         return sys.stdin.readline().strip()
 
     fromaddr = prompt("From")

Misc/NEWS

@@ -47,6 +47,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #12448: smtplib now flushes stdout while running ``python -m smtplib``
+  in order to display the prompt correctly.
+
 - Issue #13194: zlib.compressobj().copy() and zlib.decompressobj().copy() are
   now available on Windows.