[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

--- Comment #7 from github-bugzi...@puremagic.com ---
Commits pushed to master at https://github.com/D-Programming-Language/phobos

https://github.com/D-Programming-Language/phobos/commit/7cdd7098be255ec051831f9b56741701c6a1a57e
fix issue 14966: misuse of super

https://github.com/D-Programming-Language/phobos/commit/0b99239fe9722de98c5aeb65deb09a27263b2a5a
Merge pull request #4144 from rainers/issue_14966

fix issue 14966: misuse of super

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

github-bugzi...@puremagic.com changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution|--- |FIXED

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

--- Comment #6 from Rainer Schuetze  ---
> Awww, when?

I don't think this has to do with how Object.opEqual is called. The offending
lines were changed a number of times, but I'd say none of them worked correctly
(or there must have been a compiler change regarding super.calls). I suspect
the bug is also in the original commit from 2008.

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

--- Comment #5 from Sobirari Muhomori  ---
(In reply to Jacob Carlborg from comment #2)
> I suspect the issue is the super call. I'm guessing since the implementation
> of ==/!= was changed to call object.opEquals, which then calls opEquals on
> the object.

Awww, when?

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

Rainer Schuetze  changed:

   What|Removed |Added

   Keywords||pull
 CC||r.sagita...@gmx.de

--- Comment #4 from Rainer Schuetze  ---
https://github.com/D-Programming-Language/phobos/pull/4144

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

Vladimir Panteleev  changed:

   What|Removed |Added

 CC||thecybersha...@gmail.com

--- Comment #1 from Vladimir Panteleev  ---
Please post a simple test case, sample stack trace... this is not a good bug
report.

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

--- Comment #3 from Vladimir Panteleev  ---
(In reply to Jacob Carlborg from comment #2)
> It's so obvious, that's why I didn't provide a test case.

Ideally, bug reports should contain enough information so that people
unfamiliar with the code in question could reproduce the problem - this is so
anyone can check whether the bug has been fixed in the meanwhile, check if it's
a regression, reduce the test case to a minimum one etc.

--

[Issue 14966] Comparing two std.xml.Document result in infinite recursion

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14966

--- Comment #2 from Jacob Carlborg  ---
It's so obvious, that's why I didn't provide a test case. The content of the
XML doesn't matter. I added a test case with a stack trace at the bottom.

I think the issue is that implementation of Document.opEquals:

override bool opEquals(Object o)
{
const doc = toType!(const Document)(o);
return
(prolog != doc.prolog) ? false : (
(super  != cast(const Element)doc) ? false : (
(epilog != doc.epilog) ? false : (
true )));
}

I suspect the issue is the super call. I'm guessing since the implementation of
==/!= was changed to call object.opEquals, which then calls opEquals on the
object. The object will be dynamically resolved to Document and then call
Document.opEquals again, resulting in infinite recursion. I was planning to ask
about this in the newsgroup if this is a regression but forgot about it.

Test case:

$ cat main.d
import std.xml;

void main()
{
auto xml = `


`;

auto a = new Document(xml);
auto b = new Document(xml);
auto c = a == b;
}
$ dmd main.d && lldb main
(lldb) target create "main"
Current executable set to 'main' (x86_64).
(lldb) r
Process 68379 launched: '/Users/jacob/development/d/main' (x86_64)
Process 68379 stopped
* thread #1: tid = 0x4ad39f, 0x0001000156f4 main`_d_isbaseof2 + 8, queue =
'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=2,
address=0x7fff5f3fffa8)
frame #0: 0x0001000156f4 main`_d_isbaseof2 + 8
main`_d_isbaseof2:
->  0x1000156f4 <+8>:  pushq  %rbx
0x1000156f5 <+9>:  pushq  %r12
0x1000156f7 <+11>: pushq  %r13
0x1000156f9 <+13>: pushq  %r14
(lldb) bt
* thread #1: tid = 0x4ad39f, 0x0001000156f4 main`_d_isbaseof2 + 8, queue =
'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=2,
address=0x7fff5f3fffa8)
  * frame #0: 0x0001000156f4 main`_d_isbaseof2 + 8
frame #1: 0x0001000156d1 main`_d_dynamic_cast + 45
frame #2: 0x0001000361b8
main`D3std3xml31__T6toTypeTxC3std3xml8DocumentZ6toTypeFC6ObjectZxC3std3xml8Document
+ 20
frame #3: 0x0001000322f9 main`D3std3xml8Document8opEqualsMxFC6ObjectZb
+ 21
frame #4: 0x00011a59 main`D6object8opEqualsFC6ObjectC6ObjectZb +
109
frame #5: 0x000119e5 main`D6object8opEqualsFxC6ObjectxC6ObjectZb +
13
frame #6: 0x000100032334 main`D3std3xml8Document8opEqualsMxFC6ObjectZb
+ 80
frame #7: 0x00011a59 main`D6object8opEqualsFC6ObjectC6ObjectZb +
109
frame #8: 0x000119e5 main`D6object8opEqualsFxC6ObjectxC6ObjectZb +
13
frame #9: 0x000100032334 main`D3std3xml8Document8opEqualsMxFC6ObjectZb
+ 80
frame #10: 0x00011a59 main`D6object8opEqualsFC6ObjectC6ObjectZb +
109
.
.
.
frame #196537: 0x00011a59 main`D6object8opEqualsFC6ObjectC6ObjectZb
+ 109
frame #196538: 0x00011236 main`_Dmain + 102
frame #196539: 0x000100016b1c
main`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv + 40
frame #196540: 0x000100016a61
main`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv + 45
frame #196541: 0x000100016ac1
main`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZv + 45
frame #196542: 0x000100016a61
main`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv + 45
frame #196543: 0x0001000169d4 main`_d_run_main + 504
frame #196544: 0x00011254 main`main + 20
frame #196545: 0x7fff9a0295c9 libdyld.dylib`start + 1
frame #196546: 0x7fff9a0295c9 libdyld.dylib`start + 1
(lldb)

--