[Issue 8905] DList.Range: Internal error, inconsistent state
https://issues.dlang.org/show_bug.cgi?id=8905 safety0ff.bugz changed: What|Removed |Added Status|NEW |RESOLVED CC||safety0ff.b...@gmail.com Resolution|--- |FIXED --- Comment #6 from safety0ff.bugz --- Pull was merged 2 years ago. --
[Issue 8905] DList.Range: Internal error, inconsistent state
http://d.puremagic.com/issues/show_bug.cgi?id=8905 --- Comment #5 from monarchdo...@gmail.com 2012-11-01 09:53:40 PDT --- (In reply to comment #4) > (In reply to comment #3) > > [SNIP] > > Actually, I remember that I had corrected all these bugs, but had never gotten > around to committing them... I'll do it then. https://github.com/D-Programming-Language/phobos/pull/910 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8905] DList.Range: Internal error, inconsistent state
http://d.puremagic.com/issues/show_bug.cgi?id=8905 --- Comment #4 from monarchdo...@gmail.com 2012-10-30 03:28:21 PDT --- (In reply to comment #3) > [SNIP] Actually, I remember that I had corrected all these bugs, but had never gotten around to committing them... I'll do it then. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8905] DList.Range: Internal error, inconsistent state
http://d.puremagic.com/issues/show_bug.cgi?id=8905
--- Comment #3 from monarchdo...@gmail.com 2012-10-30 01:44:41 PDT ---
(In reply to comment #2)
> (In reply to comment #1)
> > I don't think there is *ANY* way to ever make this work, and I'd suggest
> > either
> > of:
> > *Re-writing the documentation.
> > *Removing the function if the documentation is correct.
> >
>
> I don't think so, either, and I agree with the recommendation.
Wait, thinking about it, technically, it could actually work, if the original
range then produced :"[1, 2, 3, 4, 7]".
The thing is that such semantics are un-natural. It would correspond to my
notion of "a Dlist is just a view into a chain of nodes". The problem is that I
*still* don't know if that would be the intended behavior...
BTW, here is a fun bug related to said "view of chain" behavior:
//
import std.container;
import std.stdio;
void main()
{
auto list = make!(DList!int)(1,2,3,4,5);
auto r = list[];
list.stableRemoveBack();
list.stableRemoveFront();
list.stableRemove(list[]);
writeln("My empty list: ", list[]);
writeln("My original slice: ", r);
}
//
My empty list: [2, 3, 4]
My original slice: [1, 5]
//
Fixing this is doable, but it makes the implementation *very* complicated
(standard dlist assumptions don't hold anymore). Not to mention it allows for
some *very* weird semantics. Not worth it, IMO.
I'd have suggested that DList be changed to have a simpler reference semantic
(all Dlist share a common payload), with explicit destruction of removed nodes
(and invalidation of ranges that index them). EG: The DList we all know and
love...
But seeing how much feedback I've received, I'm not sure I feel like pushing
for this one >:(
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[Issue 8905] DList.Range: Internal error, inconsistent state
http://d.puremagic.com/issues/show_bug.cgi?id=8905 --- Comment #2 from Ellery Newcomer 2012-10-29 17:21:16 PDT --- (In reply to comment #1) > > I think the code is invalid, that is not how "stable" is meant to be used. It > just means that the insert will not modify the order of the *other* elements > in > the list. > > The documentation states otherwise, but in this case, I think it is the > documentation that is wrong. > > When you first call "stableRemoveBack", the range becomes invalidated. That is > what the assert is telling you. And as you noted above, this violates the current semantics of stableRemoveBack. I am wondering if stableRemoveBack is intended for immutable data structures or something. It certainly doesn't seem implementable for anything in std.container. > I don't think there is *ANY* way to ever make this work, and I'd suggest > either > of: > *Re-writing the documentation. > *Removing the function if the documentation is correct. > I don't think so, either, and I agree with the recommendation. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 8905] DList.Range: Internal error, inconsistent state
http://d.puremagic.com/issues/show_bug.cgi?id=8905
monarchdo...@gmail.com changed:
What|Removed |Added
CC||monarchdo...@gmail.com
--- Comment #1 from monarchdo...@gmail.com 2012-10-29 14:51:58 PDT ---
(In reply to comment #0)
> The code:
>
> import std.container;
> import std.algorithm;
> import std.stdio;
>
> void main() {
> DList!int list = make!(DList!int)(1,2,3,4);
> auto range = list[];
> list.stableRemoveBack();
> list.stableInsertBack(7);
> writeln(list[]);
> writeln(range);
> }
>
> The fireworks:
>
> core.exception.AssertError@/usr/include/dmd-d/std/container.d(1573):
> DList.Range: Internal error, inconsistent state
I inserted that assert in the code.
I think the code is invalid, that is not how "stable" is meant to be used. It
just means that the insert will not modify the order of the *other* elements in
the list.
The documentation states otherwise, but in this case, I think it is the
documentation that is wrong.
When you first call "stableRemoveBack", the range becomes invalidated. That is
what the assert is telling you.
Case in point, in DMD 2.060, without the assert, look at what happens when you
do this:
//
import std.range;
import std.container;
import std.algorithm;
import std.stdio;
void main() {
DList!int list = make!(DList!int)(1,2,3,4);
auto range = list[];
list.stableRemoveBack();
list.stableInsertBack(7);
writeln(range);
writeln(range.retro());
}
//
[1, 2, 3, 7]
[4, 3, 2, 1]
//
Notice the '7' when iterating forward, but the 4 when iterating backwards: The
tip of the range's front is not the tail: The range got "cut" on the call to
"stableRemoveBack" and that is why the range is not happy.
I don't think there is *ANY* way to ever make this work, and I'd suggest either
of:
*Re-writing the documentation.
*Removing the function if the documentation is correct.
EDIT: ACTUALLY, one of the first things I'll propose is to reword the assert:
It makes it sound like an implementation error, when it is actually a user
error. How about: "Logic Error: The DList.range chain has been cut."
I know it might not make that much sense, but it is what is happening, and the
message *is* better. BTW, this thread might make sense of what is happening:
http://forum.dlang.org/thread/gjhclwsuqyhrimdeo...@forum.dlang.org
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