Failed assertion dialog box ATTN: Takashi Yano

André Bleau andre_bleau@hotmail.com
Thu Nov 19 14:21:40 GMT 2020


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De : Cygwin <cygwin-bounces@cygwin.com> de la part de André Bleau via Cygwin <cygwin@cygwin.com>
Envoyé : 15 novembre 2020 15:39
À : The Cygwin Mailing List <cygwin@cygwin.com>
Objet : Re: Failed assertion dialog box 
 
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De : Cygwin <cygwin-bounces@cygwin.com> de la part de André Bleau via Cygwin <cygwin@cygwin.com>
Envoyé : 15 novembre 2020 15:04
À : The Cygwin Mailing List <cygwin@cygwin.com>
Objet : Re: Failed assertion dialog box 
 
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De : Cygwin <cygwin-bounces@cygwin.com> de la part de William M. (Mike) Miller via Cygwin <cygwin@cygwin.com>
Envoyé : 15 novembre 2020 08:12
À : The Cygwin Mailing List <cygwin@cygwin.com>
Objet : Re: Failed assertion dialog box 
 
On Sat, Nov 14, 2020 at 11:49 PM Duncan Roe <duncan_roe@optusnet.com.au>
wrote:

...

>
> Sorry, should have mentioned running on Win7 Home.
>
> When I try it on my wife's Win10 system, I get the dialog box same as you.
>

That's disappointing. Thanks for the additional information, though.
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I would say we got some useful info:
1- The bug is OS specific; it occurs in Windows 10
2- Three persons were able to reproduce it on Windows 10, which improves the probability of getting fixed.

- André Bleau
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Here's some more info:

It seems the bug is related to pseudo-console support; that explains why it is Windows 10 specific. 

Experiment: 

CYGWIN=disable_pcon /usr/bin/mintty &

In the newly created window:

$ ./a.exe </dev/null >output.txt 2>&1
Aborted (core dumped)

No message box popup.

$ cat output.txt
assertion "false" failed: file "assert.cpp", line 3, function: int main()

In the original mintty window, with empty CYGWIN env variable:

$ ./a.exe </dev/null >output.txt 2>&1
Aborted (core dumped)

A message box pops

AND:

$ cat output.txt

 output.txt  is empty

So, 2 problems here.

In a CMD Window:

set path=%PATH%D:\Cygwin\bin;
a.exe <NUL: >outcmd.txt 2>&1
      1 [main] a 759 cygwin_exception::open_stackdumpfile: Dumping stack trace to a.exe.stackdump

type outcmd.txt
assertion "false" failed: file "assert.cpp", line 3, function: int main()
      1 [main] a 759 cygwin_exception::open_stackdumpfile: Dumping stack trace to a.exe.stackdump

The bug could be in cygwin or in mintty. Maybe this is something that Thomas Wolff (mintty author) or Takashi Yano  (pseudo-console support expert) would want to look at.
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OK, I opened an issue for mintty and it was quickly closed with that quote:

"Quick generic answer: if it's caused by ConPTY support, it's not related to mintty; also mintty never shows any popups.
Funny thing, though, but really: assert isn't handled by the terminal."

So the issue can only be with pseudo-console support in cygwin.

- André Bleau
- André Bleau


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