#20013: don't raise socket error when selected mailbox deleted.

I'm checking this in without a test because not much of this code
is tested and I don't have time to work up the necessary extensions
to the existing test framework.

The patch itself was tested by the person who reported the bug.

Lib/imaplib.py

@@ -1063,6 +1063,11 @@ class IMAP4:
                 del self.tagged_commands[tag]
                 return result
 
+            # If we've seen a BYE at this point, the socket will be
+            # closed, so report the BYE now.
+
+            self._check_bye()
+
             # Some have reported "unexpected response" exceptions.
             # Note that ignoring them here causes loops.
             # Instead, send me details of the unexpected response and

Misc/NEWS

@@ -24,6 +24,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #20013: Some imap servers disconnect if the current mailbox is
+  deleted, and imaplib did not handle that case gracefully.  Now it
+  handles the 'bye' correctly.
+
 - Issue #20531: Revert 3.4 version of fix for #19063, and apply the 3.3
   version.  That is, do *not* raise an error if unicode is passed to
   email.message.Message.set_payload.