[Scons-users] Intermittent Install() failure

Tue Jul 19 05:11:50 EDT 2016

An afterthought about how I had debugged similar issue - I used FileMon (or
its successor, if it exists - don't remember) to watch all the file
operations on certain path patterns, and it gave me some clue.

In my case the issue was caused by combination of NTFS hardlinks and MS VC
compiler taking non-shared ownership of a header file it used to compile
stuff while SCons tried to remove a hardlink copy of said header.

Thanks,
Vasily
19 июля 2016 г. 11:51 пользователь "Vasily" <just.one.man at yandex.ru>
написал:

> Hi Steve,
>
> What does your build do with this file except installing it? Is it used by
> a compiler or some other tool?
>
> Also, if I'm not mistaken, default SCons behavior is to remove the target
> before performing any action to regenerate it, so this might be the source
> of the exception you're seeing. There seems to be a way to turn off the
> removal part of the action, so you may want to check the manual and see if
> it helps you.
>
> P.S. Based on file path I assume you're working on Windows, is this path a
> network one?
>
> Thanks,
> Vasily
> 19 июля 2016 г. 11:02 пользователь "Hill, Steve (FP COM)" <
> Steve.Hill at cobham.com> написал:
>
>> Thanks William.
>>
>>
>>
>> I’ve checked the dependency tree and, as far as I can tell, it looks OK.
>>
>> We do have custom scanners – using env.Scanner(_scan_domain_header) – but
>> not for the files that are affected.
>>
>> As far as I can see, the fix for that Python bug never made it into 2.6.x
>> but it appears always to result in a “No child processes” OSError so I
>> don’t believe that is what I am seeing.
>>
>>
>>
>> Note that I have (temporarily) changed the decider below to simply return
>> True (without doing anything with the file) and I still see the issue so
>> the decider doesn’t seem to be relevant to the issue.
>>
>>
>>
>> Does anyone have any more ideas? This is becoming a major issue for our
>> automated builds…
>>
>>
>>
>> S.
>>
>>
>>
>>
>>
>> Steve,
>>
>> I of course should have asked the obvious question, do you know if you
>> dependency tree has missing dependencies? This tends to be a common issue.
>>
>> V/R,
>>
>> William
>>
>>
>>
>> On Fri, Jul 15, 2016 at 5:14 PM, William Blevins <wblevins001 at gmail.com>
>> wrote:
>>
>> Steve,
>>
>> I'm not aware of any specific issue with install, but there are some
>> possible issues that I am aware:
>>
>>    1. If you have custom scanners, make sure they implement from
>>    SCons.Scanner.Current and not SCons.Scanner.Base; otherwise, you might have
>>    concurrent file access between implicit scanning operations and other
>>    processes.
>>    2. There was a big subprocess bug in python 2.6 that carried through
>>    several other major versions: https://bugs.python.org/issue1731717. I
>>    would check to see that your version of 2.6 contains the patch for this
>>    issue.
>>
>> V/R,
>>
>> William
>>
>>
>>
>> On Fri, Jul 15, 2016 at 9:30 AM, Hill, Steve (FP COM) <
>> Steve.Hill at cobham.com> wrote:
>>
>> I’m having a problem where, with parallel builds (most people use 8, 12
>> or 16 threads), we occasionally get failures like the following:
>>
>>
>>
>> F:\<directory path>\hw_cfgs\1Server_1TM_6C66_2U.cfg: The process cannot access the file because it is being used by another process
>> scons: building terminated because of errors.
>>
>>
>>
>> We are running Python 2.6.5 (with pywin32) and SCons 2.3.6. This file is
>> being copied due to a Install() call. Note that, for various historical
>> reasons, we have the following decider for these Installs:
>>
>>
>>
>> def _copy_decider(dependency, target, prev_ni):
>>
>>     target = str(target.abspath)
>>
>>     dependency = str(dependency.abspath)
>>
>>     if os.path.isfile(target) and os.path.isfile(dependency):
>>
>> *        # By default, filecmp.cmp assumes that files with identical
>> os.stat signatures*
>>
>> *        # (which includes the inode) are the same file and, hence, must
>> be the same.*
>>
>> *        # However, on Windows, there is no inode - it appears to be set
>> to zero - so*
>>
>> *        # any two files with the same size and
>> access/creation/modification times*
>>
>> *        # will have the same os.stat signature, leading to a false
>> positive. For this*
>>
>> *        # reason, we must force it to do an actual file comparison by
>> setting shallow*
>>
>> *        # to False*
>>
>>         return not filecmp.cmp(target, dependency, shallow = False)
>>
>>     else:
>>
>> *        # Either one of the dependency or target isn't a file or one of
>> the files*
>>
>> *        # (presumably the target) isn't there so do the copy*
>>
>>         return True
>>
>>
>>
>> Note also that our IT department claims that virus checkers are disabled
>> within the directory where the build is being performed (and we certainly
>> have not seen any indication in the virus checker console to suggest that
>> to be incorrect).
>>
>>
>>
>> Does anyone have any thoughts as to what the problem might be?
>>
>>
>>
>> Thanks in advance,
>>
>>
>>
>> S.
>>
>>
>>
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>>
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