bug#32673: 27.0.50; wdired: broken 'wdired--restore-dired-filename-prop'

[Stephen Berman]

On Wed, 12 Sep 2018 02:32:09 +0300 Juri Linkov <juri@linkov.net> wrote:

>> The immediate cause of this is that wdired--restore-dired-filename-prop,
>> which is on after-change-functions, calls dired-get-filename without
>> making sure that the file name is not the empty string.  But it turns
>> out that using dired-get-filename in that function also doesn't work
>> with symlinks as I had thought (and tested, but evidently not enough):
>> after enabling wdired-mode but before making a change, (file-symlink-p
>> (dired-get-filename)) on a symlink returns the name of the target, but
>> as soon as a change is made, that sexp returns nil, which causes a
>> text-read-only signal.  The patch below replaces this sexp and according
>> to my tests avoids the error which breaks delete-selection-mode and also
>> most text-read-only signals (one remains: when deleting the whole link
>> name; I haven't been able to figure out how to avoid that).  The patch
>> should get more testing (in particular, is looking for the `l' flag a
>> reliable way to identify a symlink?), and an ERT test would also be
>> good, but I probably can't do either for the next few weeks, because
>> I'll be travelling.  I can install the patch before I leave, since it
>> seems at least better than the status quo, or maybe someone else can
>> take a look and either confirm that it is good enough or else come up
>> with a better fix.
>
> Thanks, since your patch fixes the reported problem, there is no reason
> to postpone installing it.  

Ok, but I'll wait another day or two, to give others a chance to object.

>                             Regarding improving the handling of symlinks,
> maybe you can use some code from dired-move-to-end-of-filename,
> especially handling dired-ls-F-marks-symlinks.

Thanks for the pointer.  I don't think I'll have time to look into that
before leaving, but maybe I can do so while I'm away, otherwise after
returning.

Steve Berman