Bug #7833: DRb has problems with BasicObject

• Status: Closed
• Assignee: seki (Masatoshi Seki)
• Target version: -
• ruby -v: 1.9.3p374
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN

[prijutme4ty (Ilya Vorontsov)]

I realized some problems with DRb and BasicObject

1. I cannot create front object of BasicObject class because DRb tries to call private_methods class

2. Call to DRb can't return instance of BasicObject class, instead it hangs.

serv.rb:

require 'drb'
$drb_uri = 'druby://localhost:1111'
class Front
def func
BasicObject.new
end
end
DRb.start_service($drb_uri, Front.new)
DRb.thread.join

conn.rb:

require 'drb'
$drb_uri = 'druby://localhost:1111'
DRb.start_service
conn = DRbObject.new_with_uri($drb_uri)
p conn.func

When after a while (tens of seconds) I break the server, client shows me trace:

conn.rb
C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:570:in load': connection closed (DRb::DRbConnError) from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:632:in recv_reply'
from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:918:in recv_reply' from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1197:in send_message'
from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1088:in block (2 levels) in method_missing' from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1172:in open'
from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1087:in block in method_missing' from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1105:in with_friend'
from C:/Ruby193/lib/ruby/1.9.1/drb/drb.rb:1086:in method_missing' from D:/programming/iogen_tools/website/server/tmp/conn.rb:5:in '

[usa (Usaku NAKAMURA)]

• Status changed from Open to Assigned
• Assignee set to seki (Masatoshi Seki)

[naruse (Yui NARUSE)]

• Target version changed from 1.9.3 to 2.6

[naruse (Yui NARUSE)]

• Target version deleted (2.6)

[jeremyevans0 (Jeremy Evans)]

• File drb-basicobject-7833.patch drb-basicobject-7833.patch added

This is still a bug in the master branch. Attached is a patch that fixes the issue. It's a decent size patch as there are many parts of drb that need to be modified to handle BasicObject instances. This patch also fixes a bug in the rescue clause of any_to_s, as sprintf does not support a %l modifier (maybe it did at some point in the past, before 1.8.7?).

• Status changed from Assigned to Closed

Applied in changeset git|d0ed935d5bf8c3fce9800742a36e44fb7f63dda4.

---

Fix some DRb issues (#2552)

• Handle BasicObject in drb

Also fix a bug in rescue clause of any_to_s because sprintf
does not handle the %l modifier.

Fixes [Bug #7833]

• Do not send a reply to the client if there is a connection error

This allows for normal TCP shutdown (fin-ack-fin-ack instead of
fin-ack-push-rst).

Patch from [e-mail] (Pierre-Alexandre Meyer).

Fixes [Bug #2339]

• Detect fork and do not reuse forked connections in drb

This associates each DRbConn with a pid, and if the pid changes,
it closes any DRbConns in the pool with a pid that no longer
matches. This fixes DRb servers from sending messages intended
for one client to another client after forking.

Fixes [Bug #2718]
Fixes [Bug #14471]