bug#48478: 28.0.50; yank-from-kill-ring and kill-ring-yank-pointer

[Juri Linkov]

>> The pointer kill-ring-yank-pointer stays at the same position:
>> before M-y, kill-ring-yank-pointer points to "evaluation",
>> and after M-y, kill-ring-yank-pointer points to "evaluation".
>
> I think this is not the optimal behavior.  The optimal behavior IMO is
> if M-y would yield the same results wrt kill-ring-yank-pointer as does
> M-y after C-y.  IOW, it would be natural if M-y invoked after a
> non-yank command would just allow a "direct access" to a specific slot
> of the kill-ring, and would otherwise work like M-y after a yank
> command.  Once again, from user's POV M-y is the same command, so
> every subtle change in the results is IMO a disadvantage, if the
> change is not a direct consequence of the differences in use cases.
>
> If you want yank-from-kill-ring to leave kill-ring-yank-pointer
> unaltered, we could move the pointer in yank-pop, after
> yank-from-kill-ring returns.  WDYT?

When yank-from-kill-ring returns an edited string,
how yank-pop could use it to adjust kill-ring-yank-pointer?