Fix debug() in notebook

[nbruin]

On sage-devel it was observed that at least in 5.7 and 5.8 we have in the notebook:

sage: 1/0
ZeroDivideError

(as expected)

sage: debug()
IndexError: string index out of range

due to inspect.getinnerframes failing on a seemingly otherwise valid traceback object.

Component: notebook

Author: Nils Bruin

Reviewer: Andrey Novoseltsev

Merged: sage-5.9.beta2

Issue created by migration from https://trac.sagemath.org/ticket/14338

[nbruin]

strip notebook frames prior to processing

[nbruin]

Author: Nils Bruin

[nbruin]

comment:1

Attachment: trac_14338-strip_frames.patch.gz

One fix is to avoid the frames on which inspect.findsource chokes, since those are frames that have to do with the notebook, not with the user code, so they don't get displayed anyway.

The other fix would be to

python/inspect.py:526

     file = getfile(object)
     sourcefile = getsourcefile(object)
-    if not sourcefile and file[0] + file[-1] != '<>':
+    if not sourcefile and (not file or file[0] + file[-1] != '<>'):
         raise IOError('source code not available')
     file = sourcefile if sourcefile else file

but that's a change to python, not to sage.

[novoselt]

Reviewer: Andrey Novoseltsev

[novoselt]

comment:2

Thanks for looking into it! The patch works for me and does what was done before in a slightly different way.

[novoselt]

comment:3

OK, I was too fast:

**********************************************************************
5 items had failures:
   2 of   4 in sage.interacts.debugger.Debug
   1 of   3 in sage.interacts.debugger.Debug.__init__
   2 of   4 in sage.interacts.debugger.Debug.curframe
   1 of   4 in sage.interacts.debugger.Debug.evaluate
   3 of   7 in sage.interacts.debugger.Debug.listing
    [23 tests, 9 failures, 1.7 s]
----------------------------------------------------------------------
sage -t --long sage/interacts/debugger.py  # 9 doctests failed
----------------------------------------------------------------------

[nbruin]

Attachment: trac_14338-doctest_fix.patch.gz

fix doctest

[nbruin]

comment:4

OK, the doctest uses a stacktrace that's shallower than will ever happen in the notebook, so when we strip off the 5 outer frames that should be removed in the notebook, we have nothing left (hence the error). Attached patch makes a deeper backtrace so that stripping off the first 5 still leaves something to test. Doctest text needs to be changed in some spots.

[novoselt]

comment:5

Looks good and all long tests pass now.

[jdemeyer]

Merged: sage-5.9.beta2