Logging synchronises input and output wrongly.

[itaibn]

In sage/misc/log.py, the following is in the documentation:

        """
        There is an off-by-one issue with IPython's input and output
        history; ``__IPYTHON__.input_hist_raw`` is a *list* containing
        the un-preparsed Sage commands. However,
        ``__IPYTHON__.output_hist`` is a dictionary whose keys are
        integers and whose values are outputs.  This is good because
        not every input has an output.

        **BUT**, the output from::
        
            __IPYTHON__.input_hist_raw[n]

        is stored in::

            __IPYTHON__.output_hist[n+1] !

        This is annoying and it may be a bug. Right now the loggers
        correct for this, but if modifying or extending this code,
        consider yourself warned.
        """        

This is incorrect. In fact, the compensation for this inside the code makes the input and output out of synchronisation. This can be seen in the following log:

Sage Log 2012-05-08-190000
1 sage: sage.misc.preparser.load(sage.misc.preparser.base64.b64decode("L2hvbWUvaXRhaWJuLy5zYWdlLy9pbml0LnNhZ2U="),globals(),False)

  2

2 sage: 1+1
3 sage: log_text()

Component: misc

Keywords: log logging

Issue created by migration from https://trac.sagemath.org/ticket/12927

[itaibn]

A patch to fix this bug

[jdemeyer]

comment:1

Attachment: trac_12927.gz

[vbraun]

comment:3

Is the patch reversed?

Also, needs commit message instead of [mq]: trac_12927 and ideally some doctest (e.g. using the IPython test shell framework or via a separate Sage session)