[Scons-users] Possible threading bug in scons

[William Blevins]

I'll take a brief look, but I am pretty busy during exam season. I have ran
heterogeneous SCons builds on 40-core servers without every running into
this, but it is still possible...

On Mon, Jan 18, 2016 at 9:46 PM, William Blevins <wblevins001 at gmail.com>
wrote:

>
>
> On Mon, Jan 18, 2016 at 2:48 PM, Tom Tanner (BLOOMBERG/ LONDON) <
> ttanner2 at bloomberg.net> wrote:
>
>> Someone here has been doing a lot of parallel builds and come across what
>> looks like a bug though I'm not sure why:
>>
>> The problem is with this bit in Taskmaster:
>>
>> def execute(self):
>> """
>> Called to execute the task.
>>
>> This method is called from multiple threads in a parallel build,
>> so only do thread safe stuff here. Do thread unsafe stuff in
>> prepare(), executed() or failed().
>> """
>> T = self.tm.trace
>> if T: T.write(self.trace_message(u'Task.execute()', self.node))
>>
>> try:
>> cached_targets = []
>> for t in self.targets:
>> if not t.retrieve_from_cache():
>> break
>>
>> The t.retrieve_from_cache ends up doing this:
>>
>> File ".../SCons/Node/FS.py", line 1778, in get_csig
>> contents = self.get_contents()
>> File ".../SCons/Node/FS.py", line 1769, in get_contents
>> contents.append('%s %s\n' % (node.get_csig(), node.name))
>> File ".../SCons/Node/__init__.py", line 784, in get_csig
>> return self.ninfo.csig
>> AttributeError: 'FileNodeInfo' object has no attribute 'csig'
>>
>> which goes away if he puts a lock in Node.get_ninfo.
>>
>> Now, the only way I can think of this triggering is if he's managed to
>> get two rules with the same target. Is that possible? and if so how can you
>> detect it? I don't like the idea of having a lock in Node.get_ninfo.
>>
>
> Two rules with the same target generate a SCons Error at SConscript parser
> time.
>
>
>>
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>>
>>
>
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