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

[Eli Zaretskii <eliz@gnu.org>]

Jared, can I ask you to look into this and share your thoughts and
comments to the proposed change?  TIA.

> Cc: 49253@debbugs.gnu.org
> From: Matt Bisson <bisson.m@gmail.com>
> Date: Fri, 8 Dec 2023 15:35:36 -0500
> 
> Right, so this silly little fix works, but it's an obvious hack.  I
> clearly don't know enough about how the key-bindings work, because I
> would have expected those set by term-mode to override those in the
> global keybindings (from xterm.el), but they don't.  The xterm.el one
> runs first.  Here's the diff:
> 
> diff --git a/lisp/term.el b/lisp/term.el
> index 81746e0c20d..e047fa767e8 100644
> --- a/lisp/term.el
> +++ b/lisp/term.el
> @@ -956,6 +956,7 @@ term-raw-map
>      (define-key map [?\C- ] #'term-send-C-@)
>      (define-key map [?\C-\M-/] #'term-send-C-M-_)
>      (define-key map [?\C-\M- ] #'term-send-C-M-@)
> +    (define-key map "\e[200~" #'term--xterm-paste)
> 
>      (when term-bind-function-keys
>        (dotimes (key 21)
> diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
> index 5ed4e46e0a5..117bd131123 100644
> --- a/lisp/term/xterm.el
> +++ b/lisp/term/xterm.el
> @@ -149,7 +149,8 @@ xterm--suspend-tty-function
>  ;; looping on read-key and buffering input for later processing.
> 
>  (defun xterm-translate-bracketed-paste (_prompt)
> -  (vector (list 'xterm-paste (xterm--pasted-text))))
> +  (unless (and (eq major-mode 'term-mode) (term-in-char-mode))
> +    (vector (list 'xterm-paste (xterm--pasted-text)))))
> 
>  (defvar xterm-rxvt-function-map
>    (let ((map (make-sparse-keymap)))
> 
> 
> On Fri, Dec 8, 2023 at 2:06 PM Matt Bisson <bisson.m@gmail.com> wrote:
> >
> > I've finally had some time to look at this and what's happening is term/xterm.el is fighting with term.el.  The bracketed paste command comes in with "\e[200~", arrives in term/xterm.el's xterm--pasted-text function first.  It correctly reads the text from the clipboard.  This is because xterm-translate-bracketed-paste is registered as a key binding for [xterm-paste] (or "\e[200~" on RXVT).
> >
> > Immediately thereafter, term--xterm-paste in term.el notices the [xterm-paste] key as well (it has also registered a binding for "raw" mode), and begins the same process of xterm--pasted-text.  At this point, there's nothing to read from read-event, and it hangs for most-positive-fixnum (basically, forever).
> >
> > So this is the root cause analysis.  Unfortunately, naively removing the key binding from term.el does not work, because the pasted text must be inserted via term-send-raw-string.
> >
> > -Matt
> >
> > On Sat, Jul 16, 2022 at 3:13 PM Matt Bisson <bisson.m@gmail.com> wrote:
> >>
> >> For sure.  Even in emacs 28.2, if I want to paste something into the terminal buffer, I have to switch to line mode, and back when I'm done.  You just can't paste into the terminal buffer in terminal emacs in key mode.
> >>
> >> On Sat, Jul 16, 2022, 8:21 AM Lars Ingebrigtsen <larsi@gnus.org> wrote:
> >>>
> >>> Matt Bisson <bisson.m@gmail.com> writes:
> >>>
> >>> > I have observed this behavior from MacOS, with an Emacs running either
> >>> > locally on MacOS, or over SSH (running on Linux).  Without any
> >>> > modifications, a -Q invocation causes "xterm--pasted-text: Failed
> >>> > select: Invalid argument", but without -Q it simply hangs.
> >>>
> >>> (I'm going through old bug reports that unfortunately weren't resolved
> >>> at the time.)
> >>>
> >>> Are you still seeing this problem in recent Emacs versions?
> >>>
> >>> --
> >>> (domestic pets only, the antidote for overdose, milk.)
> >>>    bloggy blog: http://lars.ingebrigtsen.no
> 
> 
> 
>