%%time magic prevents assignment

The %%time cell magic is preventing me from binding names. I found this in notebook code on Travis (py 3.6) and reproduced it locally (py 3.7) in notebook and in ipython at the terminal. It doesn’t seem to apply to all cell magics:

Python 3.7.2 | packaged by conda-forge | (default, Mar 19 2019, 20:46:22)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.4.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: %%time
   ...: foo = "bar"
   ...:
   ...:
CPU times: user 3 µs, sys: 0 ns, total: 3 µs
Wall time: 6.91 µs

In [2]: foo
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-2-f1d2d2f924e9> in <module>
----> 1 foo

NameError: name 'foo' is not defined

In [3]: %%prun
   ...: baz = "qux"
   ...:
   ...:
         3 function calls in 0.000 seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    0.000    0.000 {built-in method builtins.exec}
        1    0.000    0.000    0.000    0.000 <string>:2(<module>)
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

In [4]: baz
Out[4]: 'qux'

Confirmed that 7.3.0 worked fine locally.

[Carreau]

We’re planning to fix it as soon as we have time; it will likely make it to the 7.5 release that I’ll try to make before end of month.

[wanick]

By the way, in “%%timeit” the situation is exactly the same, but at least it behaves predictably