bug#7041: comint seems to truncate from places other than the top

[Reuben Thomas]

On Tue, 8 Dec 2020 at 22:31, Lars Ingebrigtsen <larsi@gnus.org> wrote:

Reuben Thomas <rrt@sc3d.org> writes:

> If I try it now, it doesn't seem to truncate the buffer as expected: for example
>
> emacs -Q
> M-: (add-to-list 'comint-output-filter-functions 'comint-truncate-buffer)
> M-x term
> C-c M-x set-variable comint-buffer-maximum-size 256 ; do this after M-x term
> because before comint-buffer-maximum-size is not defined
> $ seq 1 1024
>
> The entire output is retained, and not truncated. Truncation seems to happen at
> 2048 lines. This does not even correspond to the original value of the variable
> (1024).

I'm not getting any truncation...  but that variable is about comint
buffers, like in `M-x shell' and the like.  Is term-mode a comint
buffer?  It's not derived from comint-mode, so I'm not sure whether this
is supposed to work there?

Ah, that would seem to explain it! Indeed, `term-buffer-maximum-size` defaults to 2048.

So this bug report is based on a misunderstanding, and you can close it, sorry!

In investigating, I noticed that the following text in term.el appears to be out of date:

;; Brief Command Documentation:

… for example:

;; M-s     comint-next-matching-input    Next input that matches ← This is not true! It is bound to term-next-matching-input.

Is there any point retaining this documentation at the top of the file where it doesn't appear in the manual or any docstring?

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