Re: M-x term off-by-one problem in ESC[xM processing?

[Mark Plaksin]

Mark Plaksin <address@hidden> writes:

> Mark Plaksin <address@hidden> writes:
>
>> Hiho:
>>
>> - Save the attached file as 'testfile'
>> - Create a 125x23 M-x term window (same problem with 80x23) .
>> - At the shell prompt, run 'vi testfile' with the attached file 
>> - Type C-d to tell vi to scroll down
>> - The first line will contain "12" and you'll see that the line for "22" is
>> blank.  That blank line is the problem.
>>
>> The problem seems to be in term-delete-lines (or the argument passed to it
>> from the `M' case of term-handle-ansi-escape).  In edebug these lines from
>> term-delete-lines move point down one too few lines and then insert a
>> newline which wipes out "22":
>>
>>     (term-down (- term-scroll-end save-current-row lines))
>>     (term-insert-char ?\n lines)
>
> Adding '(forward-line 1)' after those two lines fixes the test case for me
> but I'm not sure whether it's the right fix.

term-insert-lines seems to have a similar problem.  You can use the same
test case as above but play with vi's C-u instead of C-d.  Adding
'(forward-line 1)' after these lines fixes it for me:

      (when (>= (+ save-current-row lines) term-scroll-end)
        (setq lines (- lines (- (+ save-current-row lines) term-scroll-end))))
      (term-down (- term-scroll-end save-current-row lines)))

Again, it's not clear to me that this is the right fix.  If all my M-x term
problems go away then maybe it :)  It will take me a week or so to see
whether my problems are gone.