Issue #10031 has been updated by Eric Wong.


 Setting SO_KEEPALIVE on the socket will help, but that still takes at
 least 2 hours to detect on a stock Linux system.  Do you want to set a
 shorter keepalive, or is ~2 hours OK?
 
 You can change the interval using OS-specific knobs (e.g. sysctl).
 
 Totally untested one line patch here:
 
 	--- a/lib/net/imap.rb
 	+++ b/lib/net/imap.rb
 	@@ -1053,6 +1053,7 @@ module Net
 	       @tagno = 0
 	       @parser = ResponseParser.new
 	       @sock = TCPSocket.open(@host, @port)
 	+      @sock.setsockopt(:SOL_SOCKET, :SO_KEEPALIVE, 1)
 	       begin
 		 if options[:ssl]
 		   start_tls_session(options[:ssl])

----------------------------------------
Bug #10031: Net::IMAP idle can still block a thread forever.
https://bugs.ruby-lang.org/issues/10031#change-47750

* Author: James Pike
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
When calling Net::IMAP idle often errors will go unnoticed forever, simply leaving the Thread that called "idle" blocking forever.

For example try bringing your internet connection down whilst a thread is calling the idle method, the calling thread will now be blocked forever.

I've encountered this issue also without losing my internet connection, sometimes the remote server will disconnect the client and the client will never notice leading to the same issue.



-- 
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