qtconsole truncates help

[pratikmallya]

The Ipython shell opened with qtconsole option (i.e ipython qtconsole) truncates the help message obtained by the ?? magic. i.e

In [1]: import string
In [2]: string??

Gives:

            lineno = len(lines)
        raise ValueError('Invalid placeholder in string: line %d, col %d' %
                         (lineno, colno))

    def substitute(self, *args, **kws):
        if len(args) > 1:
            raise TypeError('Too many positional arguments')
        if not args:
            mapping = kws
        elif kws:
            mapping = _multimap(kws, args[0])
        else:
            mapping = args[0]
        # Helper function for .sub()
        def convert(mo):
            # Check the most common path first.
            named = mo.group('named') or mo.group('braced')
            if named is not None:
                val = mapping[named]
                # We use this idiom instead of str() because the latter will
                # fail if val is a Unicode containing non-ASCII characters.
...

This bug is observed on Win32 and OSX. IPython itself (without qtconsole) does not exhibit this problem.

[takluyver]

I was about to say I couldn't replicate it, but then I tried on Python 2, where the string module is longer. I think it just exceeds the maximum number of lines we keep in the console, so the top bit is cut off before you see it. We could just increase the number of lines we keep, though that would only delay the problem until you do the same with an even longer module.

[pratikmallya]

It would make sense to make it at least as large as the largest module in the standard library. Otherwise maybe some kind of paging solution? But that might require more development time than you have the bandwidth for

[takluyver]

We already consider that paging, it just doesn't page enough.

[minrk]

should be fixed by #5961.