bug#21139: 25.0.50; shell-mode doesn't respect comint-scroll-to-bottom-on-output/input

[Glenn Morris]

Artur Malabarba wrote:

> 1. Set `comint-scroll-to-bottom-on-output` and
> `comint-scroll-to-bottom-on-input` to nil via the customize interface
> (or via `setq-default`)
> 2. Run `M-x shell`
> 3. Run a couple of shell commands so you have enough output to fill
> the screen (`ls -al ~/` should do it).
> 4. Hit `C-l` twice so point is at the top of the screen.
> 5. Type `date` on the prompt and hit `RET`.
> 6. The window scrolls until point is at the bottom.

I think this is a misunderstanding.
Try (in a shell buffer with more than one page of output present):

sleep 5; date

and scroll Emacs to the top of the shell buffer before the sleep ends.
Compare the behaviour with comint-move-point-for-output nil and non-nil.