bug#31236: [PATCH] Fix pre- and post-command-hook errors in term.el

[Phil Sainty <psainty@orcon.net.nz>]

Bug and proposed fix confirmed and tested here.

This was an oversight on my part from #24837.

The suggested patch seems sensible to me.  If others agree, I think
this should be committed to the emacs-26 branch.


-Phil


On 2018-04-22 15:41, Karl Otness wrote:
> As far as I can tell there isn't an existing bug report for this
> issue. It is very minor but I have attached a fix. This affects Emacs
> 26.1-rc1 `term' and `ansi-term'. In char mode term installs functions
> in both pre- and post-command-hooks. After the process exits both of
> these hooks produce errors and then are removed by Emacs after
> printing a message.
> 
> Both of these hooks are re-installed when entering char mode and
> removing them if they are not present will do nothing. To produce this
> change, I took the remove-hook lines used when entering line mode and
> placed them in `term-handle-exit'.
> 
> To reproduce the issue in 26.1, M-x term, exit the running process and
> execute any command (i.e. move point). In *Messages* there should be
> the following lines:
> 
> Error in pre-command-hook (term-set-goto-process-mark):
> (wrong-type-argument processp nil)
> Error in post-command-hook (term-goto-process-mark-maybe):
> (wrong-type-argument processp nil)
> 
> The error seems to come up from `process-mark'. After this change,
> these errors no longer appear as the hooks are removed. I have
> attached a patch which applies this change to current master.
> 
> Thank you,
> Karl