IPython console freezes if trying to print a DateAndTime

[Andrei Savici]

The simplest example to reproduce:

print DateAndTime(1)

Old description:

In MantidPlot, type in the ipython interpreter

w=Load('CNCS7860')
r=w.getRun()
p=r.getProperty('Speed4')
print p.firstTime()

The console freezes up

[Russell Taylor]

This seems to be an IPython bug - try it in a standalone IPython qtconsole and you'll see the errors. You do get the prompt back in that case but it becomes useless.

[Russell Taylor]

It seems to boil down to the str method on the DateAndTime export (in ​PythonInterface/mantid/kernel/src/Exports/DateAndTime.cpp) sending back the result of a call to boost::posix_time::to_iso_extended_string(). If you switch it to calling DateAndTime::toSimpleString instead of DateAndTime::toISO8601String then things are fine. Since it's returning a string in either case, IPython must be trying to do something clever when it thinks it's a date.

[Russell Taylor]

Here's an even simpler way to demonstrate the problem, and one that's independent of Mantid so I can feed it back to the IPython people:

print '2013-11-05T16:36:22.100000002'

[Russell Taylor]

Reported to IPython: ​https://github.com/ipython/ipython/issues/4493

[Russell Taylor]

Re #8351. Append a space to the string representation.

This is to get around a bug in IPython 1.1. The space is added to the representation only on the python side, not the C++ side. I believe this will have minimal/zero real impact and avoids crashing the IPython console.

Changeset: 46205ee84f589acf250a6fe170f6f2cda5be0cc3

[Russell Taylor]

Re #8351. Amend tests to account for the additional space.

Changeset: e96a6647aa4ea9cb33d82ffa0e1bcddd3015d2fe

[Russell Taylor]

This represents the minimal change that solves the problem. There has been some talk of converting things to be Python datetime objects on the Python side, but that's beyond the scope of this fix.

To test: Make sure that the scriptlets above can be run without bringing down the IPython console.

[Andrei Savici]

Merge remote-tracking branch 'origin/bugfix/8351_ipython_datetime_error'

Full changeset: ​72a3f99a0f67a71987ed66099ab913ff0c163b62

[Andrei Savici]

Works. The time string can also be used to generate new time series properties (see comment ticket #8301)

[Stuart Campbell]

This ticket has been transferred to github issue ​9196