[pypy-dev] Debugging aid

[Armin Rigo]

Hello,

There are a few "para-PyPy" tasks that we should consider for the near future
too (like, during the sprint):  it would be extremely helpful for example to
have better debugging tools.  A PyPy traceback is, as you know, a lots of
pages of unhelpful data.

The kind of thing that would help is a shell-like window into which the
debugged program can "print" quite a lot of information, which can be expanded
or contracted by a mouse click or keystroke; e.g. only show the app-level
traceback, but each step in there can expand to the corresponding interp-level
traceback; each step in there expands in the local variables, the objects
expand into their attributes, etc...

I'm sure this already exists, but there is still a bit of work to integrate
something like that with PyPy (e.g. know about the two app- and interp-
levels).  It should also get integrated with the (new) test suite, to directly
inspect failing tests.

If you are more graphically oriented, there is the control flow viewer at
pypy.translator.tool.pygame.graphviewer that needs more work.  I am pretty
sure we will need a good debugging tool to understand what is going on when we
start annotating larger programs.  I bet it should have a history, e.g. record
all the annotation steps as they progress and redo previous blocks and allow
browsing through these "revisions".  It should also have "zooming", at least
to switch between a program-wide view of the function call graph and the
control flow graph inside of a particular function.

These are at least the basic tools that would help quite a bit in PyPy
debugging...


A bientôt,

Armin.