bug#49253: 27.2; Emacs non-responsive when pasting into terminal-mode

[Matt Bisson <bisson.m@gmail.com>]

That's described in the initial report.  I see it's called "term-mode"
not "terminal-mode" which was a brain-fart on my part.  The steps
(term-mode in step 2):

1. Start "emacs -nw" <ret>
2. M-x term <ret> <ret>
3. In another application (for the purposes of "exact keystroke, let's
say, Alt-TAB to Firefox"), copy some text into the clipboard, it
doesn't matter what.
4. Return to the Emacs session (click on the Terminal emulator,
Alt-TAB, whatever*), and paste into the terminal (I used Command-V).
4* To be clear, return the cursor to the term-mode buffer (e.g., C-b
*terminal* <ret>).

Inject any mount of delays or operations between steps 1, 2, 3, and 4.
The bug essentially is "if you ever paste into term-mode buffers, you
lose.




On Mon, Jun 28, 2021 at 2:37 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Matt Bisson <bisson.m@gmail.com>
> > Date: Mon, 28 Jun 2021 14:11:56 -0400
> > Cc: 49253@debbugs.gnu.org
> >
> > No.  (Unless I'm misunderstanding what you're asking) the problem can
> > occur at any time.  It's in response to simply pasting from the
> > clipboard into a terminal application.  I can start Emacs, run for
> > days normally -- using terminal-mode, editing files, and so forth.
> > The second I go into the terminal-mode buffer and paste from the
> > (Windows, Mac, whatever) clipboard (NOT using the Emacs yank command),
> > the problem happens.
>
> Wait a minute: what do you mean by "terminal-mode buffer" into which
> you need to go?  More generally, can you describe a detailed recipe
> for reproducing the problem on your system, keystroke by keystroke?
>
> > > No, it's the other way around: you start Emacs from GDB.  There are
> > > some instructions in etc/DEBUG.
> >
> > Yes, I do know that's what you mean :) but it's not as if Emacs is
> > going to crash, and stop in the debugger.
>
> You are investigating the error message saying "Failed select".
> Search the *.c files for that text, and you will find only 3 instances
> of it.  Put a breakpoint in all these 3 places, then do whatever it
> takes to reproduce the problem, and you will be able to collect the
> information I asked about.