[Scons-users] Internal Error: No dependency cycle found

[Brian Cody]

I'd like to add to this if I can. We have an odd situation which is similar
to this one. If we get a build failure making target A, while target B is
also being built, it won't just fail for A, it'll also print a gigantic "no
dependency cycle" error for B. It just adds a lot of cruft to the output
that makes it difficult to see the real problem.

If this could be related I could come up with a sample dependency tree. In
the mean time we've just been living with it.
On Nov 10, 2015 13:07, "William Blevins" <wblevins001 at gmail.com> wrote:

> That error confuses me somewhat.  I'm not sure why not having a dependency
> cycle is an error; that should be a good thing...
>
> Can you post a minimum SConscript sample that yields the problem?
>
> V/R,
> William
>
> On Tue, Nov 10, 2015 at 5:09 PM, Stefan Ross <stefan at electricimp.com>
> wrote:
>
>> Hi all,
>>
>> I'm hoping you can help with what looks like a bug, but could be an
>> artifact of how I've designed my SConscript files.
>>
>> I'm seeing the following error when doing parallel builds (-j4):
>>
>> scons: done building targets.
>> Traceback (most recent call last):
>>   File "/usr/local/lib/scons-2.4.0/SCons/Script/Main.py", line 1371, in
>> main
>>     _exec_main(parser, values)
>>   File "/usr/local/lib/scons-2.4.0/SCons/Script/Main.py", line 1334, in
>> _exec_main
>>     _main(parser)
>>   File "/usr/local/lib/scons-2.4.0/SCons/Script/Main.py", line 1099, in
>> _main
>>     nodes = _build_targets(fs, options, targets, target_top)
>>   File "/usr/local/lib/scons-2.4.0/SCons/Script/Main.py", line 1296, in
>> _build_targets
>>     jobs.run(postfunc = jobs_postfunc)
>>   File "/usr/local/lib/scons-2.4.0/SCons/Job.py", line 111, in run
>>     self.job.start()
>>   File "/usr/local/lib/scons-2.4.0/SCons/Job.py", line 429, in start
>>     self.taskmaster.cleanup()
>>   File "/usr/local/lib/scons-2.4.0/SCons/Taskmaster.py", line 1043, in
>> cleanup
>>     raise SCons.Errors.UserError(desc)
>> UserError: Found dependency cycle(s):
>>   Internal Error: no cycle found for node <deleted>
>>  (<SCons.Node.FS.File object at 0x40d4360>) in state pending
>>   Internal Error: no cycle found for node <deleted>
>>  (<SCons.Node.FS.File object at 0x40ca1d0>) in state pending
>>   Internal Error: no cycle found for node <deleted>
>>  (<SCons.Node.FS.Dir object at 0x34a7e60>) in state pending
>>
>>
>> scons: *** Found dependency cycle(s):
>>   Internal Error: no cycle found for node ...
>>
>> I see a range of similar symptoms:
>>
>> 1)  When the error is as above, if I build again, there are still some
>> more targets which get built, i.e. the build has finished before all
>> targets have been built.
>> 2)  Sometimes I get failures because a source file is not found when
>> building a target.  I've confirmed using --tree that the dependency has
>> been detected by scons.
>>
>> Clues:
>>
>> 1) In case 2 above, the target is being built using a Pseudo-builder
>> (AddMethod)
>> 2) We've been using this build system for a long time without these
>> issues. The main thing I've changed recently is using a lot more
>> variant_dir builds.  The targets I have most problems with were originally
>> built in SConstruct.  They are now built in a SConscript file in the same
>> directory as the SConstruct, using a variant_dir.
>>
>> Any suggestions for how I can proceed to debug?
>>
>> Thanks
>>
>> Stefan
>>
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>>
>>
>
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