The following may be related, I encountered it doing some administration in
our notebooks (sagenb). The following happens in both Sage 7.4 and 7.5 (it
executes the orders but the warning may suggest some issue in the
relationship of sagenb and ipython). No warning in 7.3
sage: import sys
sage: 1+1
2
sage: import sagenb.notebook.notebook
sage: 1+1
2
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-4-4cc2ceee564b> in <module>()
----> 1 Integer(1)+Integer(1)
/usr/local/sage-7.4/local/lib/python2.7/site-packages/IPython/core/displayhook.pyc
in __call__(self, result)
244 self.start_displayhook()
245 self.write_output_prompt()
--> 246 format_dict, md_dict = self.compute_format_data(result)
247 self.update_user_ns(result)
248 self.fill_exec_result(result)
/usr/local/sage-7.4/local/lib/python2.7/site-packages/IPython/core/displayhook.pyc
in compute_format_data(self, result)
148
149 """
--> 150 return self.shell.display_formatter.format(result)
151
152 # This can be set to True by the write_output_prompt method in
a subclass
/usr/local/sage-7.4/local/lib/python2.7/site-packages/sage/repl/display/formatter.pyc
in format(self, obj, include, exclude)
158 # First, use Sage rich output if there is any
159 PLAIN_TEXT = u'text/plain'
--> 160 sage_format, sage_metadata = self.dm.displayhook(obj)
161 assert PLAIN_TEXT in sage_format, 'plain text is always
present'
162 if sage_format.keys() != [PLAIN_TEXT]:
TypeError: 'NoneType' object is not iterable
El miércoles, 8 de febrero de 2017, 8:28:27 (UTC+1), Enrique Artal escribió:
>
> I start a new thread in this list as a continuation of "How to limit heavy
> computations" in sage-support. I try to summarize the problem. In my
> University, we have two servers to run math labs; it is done in several
> instances of sagenb using server_pool to enhance (at least a little bit)
> security. The sagenb instances are launched with ulimit options but it
> seems they have no effect.
> In the first term of this academic year, we had several issues affecting
> the use of this server. Some students started long loops or heavy
> computations that stop the server (basically their computations blocked one
> instance and the error messages of the nginx processes grew so much that
> filled the hard disk). After restarting the machines, the problems came
> back again; at this point, when we detected such a process it was
> immediately stopped, but for some reason its instance of sagenb became
> unusable, causing problems to other students, since it needed restarting
> (and someone to do it). It was possible (not easy, thanks to Jori
> Mäntysalo) to identify the actual owner of the process, since stopping the
> computation by himself caused less harm.
>
> Using ulimit in the OS, namely with the restrictions hard "as 6000000"
> and "hard cpu 10", it worked. If a computation was too heavy, the
> process stopped with some error message, but the instance was usable by any
> other user of the sagenb instance (including the person with the long
> computation). This was true for Sage 7.3, but no more in Sage 7.4 (and 7.5)
> where the process was stopped by the instance became unusable in few
> minutes.
>
> Dima Pasechnik proposed to git-bisect and with the help of Miguel Marco, I
> think I found the patch causing this behavior. I started checking with 7.4
> beta and rc and I saw that beta0 had the issue. Looking at the history of
> changes, it worked after
> 2b3eb14 Trac #20621: Simpler code and better error messages in Sequence()
> and it didn't work after
> 9831d4b Trac #21006: Upgrade to IPython 5.0
>
> Is there any chance to look into this change in order to localize and
> solve the problem?
>
> Regards, Enrique.
>
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