Michael Heerdegen <michael_heerdegen@web.de> writes:

>> Well, there are exactly 100 files.  So it processed 62 files twice,
>> compressing them first and then uncompressing them again (or skipped
>> some and processed other even more).
>
> It could be that the order of the marked files changed after
> reverting.
>
> But even if not: if you look at the use of the variable
> `next-position' in `dired-map-over-marks', it is also possible to get
> such an effect if the line lengths change.
>
> So the command `dired-do-compress' is not robust against this effect.
> Other commands calculate the complete list of marked files first,
> `dired-do-chxxx' and `dired-do-chmod' for example.  So I think it is
> not unavoidable that it is like that.

What is the reason that there are two different approaches to process
all marked files, i.e., dired-map-over-marks vs. dired-get-marked-files?

Bye,
Tassilo