vm-pop-make-session goes into an infinite loop

[Uday Reddy]

Alan Wehmann provided this backtrace (viewmail-bugs, 2012-02-15)

--------------------- backtrace ---------------------------------

Debugger entered--Lisp error: (error "Variable binding depth exceeds max-specpdl-size")
  vm-parse("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd" "\\([^:]+\\):?" 1 5)
  vm-pop-parse-spec-to-list("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  byte-code [removed]
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  vm-pop-make-session("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd")
  byte-code [removed]
  vm-pop-move-mail("pop:127.0.0.1:110:pass:Alan.Wehmann:fakepwd" "c:/cygwin/home/INBOX.crash")
  vm-get-spooled-mail-normal(t)
  vm-get-spooled-mail(t)
  vm-get-new-mail(nil)
  call-interactively(vm-get-new-mail nil nil)

------------------ end of backtrace -----------------------------

[Uday Reddy (reddyuday)]

The revisions that have been made to vm-imap-make-session need to be copied to vm-pop-make-session.

[Tom Karzes (karzes)]

I am getting this exact same bug. I have been using VM for many years, and never saw this problem until a recent Ubuntu upgrade. I upgraded to Ubuntu 16.04.1 LTS. I'm running GNU Emacs 24.5.1 (Ubuntu 46.1), and VM 8.2.0b.

Now I am experiencing several problems getting VM to pull my mail from my POP server, and when it does try to, I'm usually getting this error. The backtrace looks virtually identical the one posted here (the only real difference is the site address and login info).

What should I do to fix this? Any help would be greatly appreciated.

[Uday Reddy (reddyuday)]

I have retagged the bug to be put into the 8.2.0 release.

At the moment, the only version that will work is the trunk. You can download the Code page or set up a bzr link as described in the README file.

[Tom Karzes (karzes)]

Thanks for the quick response. I'm trying to understand what the simplest solution for me will be. If this fix is likely to be distributed by Ubuntu in a week or two, then I'll probably just wait for it. If not, then I need to decide if it's worth it to diverge from the Ubuntu releases and manually install the trunk. I'm reluctant to go to that much effort, but I'd also prefer not to be forced to switch to another mail reader like Thunderbird.

One thing that confuses me is that it looks like 8.2.0b was released in 2011, yet I had not experienced the problem until less than a week ago, in spite of doing regular upgrades. Was Ubuntu releasing an earlier version that predated the bug all this time?? Unfortunately, I can no longer determine what version of Emacs or VM I was using last week.

[Tom Karzes (karzes)]

I realized the simplest work-around for me was to simply switch from POP to IMAP (which luckily was an option for me). It seems to be working for me, but I really wish it hadn't been necessary.

I do hope a stable release can be made soon for distribution with Ubuntu. At present, POP is unusable with the current Ubuntu release of VM, which I would say is a very serious problem, and quite unexpected. (I also encountered bug 913005, but this was minor in comparison, and in fact there's a very simple work-around for it, which I posted on that thread.)

I do appreciate all of the hard work that goes into maintaining and enhancing VM, and I would like to thank the developers for their efforts. I'd just like to see a little more care put into avoiding releases that break major functionality.

[Uday Reddy (reddyuday)]

Tom, if VM is important to you, your best bet is to maintain it yourself
instead of depending on Linux distributions. It is fairly easy and the
README and INSTAL files tell you exactly what to do.