Christian Franke wrote:
> Corinna Vinschen wrote:
>> On Nov 20 10:40, Corinna Vinschen wrote:
>>> Hi Christian,
>>>
>>> This puzzles me:
>>>
>>> On Nov 17 21:25, Christian Franke wrote:
>>>> @@ -610,7 +607,7 @@ get_by_id_table (by_id_entry * &table, 
>>>> fhandler_dev_disk::dev_disk_location loc)
>>>>     if (!table)
>>>>       return (errno_set ? -1 : 0);
>>>>   -  /* Sort by name and remove duplicates. */
>>>> +  /* Sort by name and mark duplicates. */
>>>>     qsort (table, table_size, sizeof (*table), by_id_compare_name);
>>>>     for (unsigned i = 0; i < table_size; i++)
>>> by_id_compare_name only compars the actual names...
>>>
>>>>       {
>>>> @@ -619,12 +616,13 @@ get_by_id_table (by_id_entry * &table, 
>>>> fhandler_dev_disk::dev_disk_location loc)
>>>>       j++;
>>>>         if (j == i + 1)
>>>>       continue;
>>>> -      /* Duplicate(s) found, remove all entries with this name. */
>>>> -      debug_printf ("removing duplicates %d-%d: '%s'", i, j - 1, 
>>>> table[i].name);
>>>> -      if (j < table_size)
>>>> -    memmove (table + i, table + j, (table_size - j) * sizeof 
>>>> (*table));
>>>> -      table_size -= j - i;
>>>> -      i--;
>>>> +      /* Duplicate(s) found, append "#N" to all entries. This never
>>> ...but the names are identical.  So the *order* within the identically
>>> named entries depends on qsort's reshuffling of table
>>> entries.  Which in turn depends on outside factors like number of table
>>> entries and the ultimate position of the identical entries within the
>>> ordered table.
>>>
>>> Having said that, I don't see how adding ordinals to the names can be
>>> unambiguous.  AFAICS, the numbers may change by just adding another
>>> disk (USB Stick) to the system...
>> Oops, that's not exactly what I was trying to say, sorry.
>>
>> The problem is not adding ordinals to the name, AFAICS, the problem is
>> that the sorting function by_id_compare_name is not up to the task to
>> make sure the order is unambiguous within the entries of identical name.
>
> That's correct, thanks for catching. qsort is not a stable sort. 
> Changing drives outside the duplicate range may also change the order 
> within the range. Could be fixed by a lexicographic compare of {name, 
> drive, part}.
>

Attached.