• Ellery Newcomer (10/10) Apr 05 2010 Hey folks,
• Walter Bright (4/17) Apr 06 2010 If you can turn this into a standalone reproducible test case, please do...
• Steven Schveighoffer (9/19) Apr 06 2010 Others have seen similar issues, can you email me directly, and perhaps ...
• Steven Schveighoffer (14/36) Apr 06 2010 Thanks to Ellery's help, I found another bug in the new array append cod...
• Jordi (4/8) Apr 09 2010 I confirm that with the patch in dmd 2.0.43 my crash problem is gone.

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

Hey folks,

I've got this screwy problem with my old version of dmdz.

One of the functions runs through a loop that appends to a string[] 
about four or five times. When it's chewing through a large amount of 
source code, maybe 1 call out of 200 the third element of the array gets 
corrupted just after an append.

duping the string that gets appended has no effect.

Trying to print out the pointer addresses to the strings does seem to 
get rid of the problem.

I'm using dmd 2.042; it doesn't seem to happen on 2.040

Walter Bright <newshound1 digitalmars.com> writes:

Ellery Newcomer wrote:
 I've got this screwy problem with my old version of dmdz.
 
 One of the functions runs through a loop that appends to a string[] 
 about four or five times. When it's chewing through a large amount of 
 source code, maybe 1 call out of 200 the third element of the array gets 
 corrupted just after an append.
 
 duping the string that gets appended has no effect.
 
 Trying to print out the pointer addresses to the strings does seem to 
 get rid of the problem.
 
 I'm using dmd 2.042; it doesn't seem to happen on 2.040

If you can turn this into a standalone reproducible test case, please do so and 
put it on bugzilla. Memory corruption problems are the worst, so doing this 
would be a big help.

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Mon, 05 Apr 2010 20:06:30 -0400, Ellery Newcomer  
<ellery-newcomer utulsa.edu> wrote:

 Hey folks,

 I've got this screwy problem with my old version of dmdz.

 One of the functions runs through a loop that appends to a string[]  
 about four or five times. When it's chewing through a large amount of  
 source code, maybe 1 call out of 200 the third element of the array gets  
 corrupted just after an append.

 duping the string that gets appended has no effect.

 Trying to print out the pointer addresses to the strings does seem to  
 get rid of the problem.

 I'm using dmd 2.042; it doesn't seem to happen on 2.040

Others have seen similar issues, can you email me directly, and perhaps we  
can get to the bottom of it?

We had memory corruption issues I introduced with my array append patch in  
2.041, and I thought I squashed them all, but I should be able to find the  
bug reasonably quickly if I have a reproducible test case.

Thanks,

-Steve

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Tue, 06 Apr 2010 08:12:55 -0400, Steven Schveighoffer  
<schveiguy yahoo.com> wrote:

 On Mon, 05 Apr 2010 20:06:30 -0400, Ellery Newcomer  
 <ellery-newcomer utulsa.edu> wrote:

 Hey folks,

 I've got this screwy problem with my old version of dmdz.

 One of the functions runs through a loop that appends to a string[]  
 about four or five times. When it's chewing through a large amount of  
 source code, maybe 1 call out of 200 the third element of the array  
 gets corrupted just after an append.

 duping the string that gets appended has no effect.

 Trying to print out the pointer addresses to the strings does seem to  
 get rid of the problem.

 I'm using dmd 2.042; it doesn't seem to happen on 2.040

 Others have seen similar issues, can you email me directly, and perhaps  
 we can get to the bottom of it?

 We had memory corruption issues I introduced with my array append patch  
 in 2.041, and I thought I squashed them all, but I should be able to  
 find the bug reasonably quickly if I have a reproducible test case.

Thanks to Ellery's help, I found another bug in the new array append code  
that can corrupt memory in certain cases.

If any of you need this fix right away and are comfortable rebuilding  
druntime and phobos, the patch can be found here:

http://www.dsource.org/projects/druntime/changeset/282?format=diff&new=282

You may have to tweak things a bit to get the patch to work, or you can  
just make the changes yourself (they are quite small).  For instance, I  
had to change the file to unix file format to get the patch applied on  
linux.

I expect a new dmd will be released in the near future to fix this issue.   
My apologies to those who have wasted time trying to debug this...

-Steve

Jordi <jordi rovira.cat> writes:

Steven Schveighoffer wrote:

 I expect a new dmd will be released in the near future to fix this 
 issue.  My apologies to those who have wasted time trying to debug this...
 
 -Steve

I confirm that with the patch in dmd 2.0.43 my crash problem is gone. 
Thanks for the fix and the test case!

j.