Edward Peschko wrote:
All,
I've been looking at the trace module, and although it looks useful, I'm
surprised that there aren't a couple of features that I would have thought
would be fairly basic. So, does trace support (for the --trace option):
I have never used the trace module but decided to try it out, following
the simple example in the docs with a simple function. It seems a bit
underdocumented, so I presume help with that would be welcome. I also
found deficiencies in the operation, though different from you.
- indentation tracking stacklevel (where each function is prefixed
by tabs equal to the number of stacklevels deep in the program)
Trace already does one space indents for modules after the first
--- modulename: threading, funcname: settrace
--- modulename: compare, funcname: lt_iw
and lines after the first
compare.py(47): while m != 0 and n != 0:
compare.py(48): m, n = m-1, n-1
That would have to be eliminated, at least when stack indents were on.
Tabs are nasty when interpreted as 8 chars. If added, the user should
specify the indent: indent = ' ', for instance, for 2 space indents.
- output to something other than sys.stdout (eg. output to a file
specified either by environmental variable or by parameter).
That seems reasonable. It also seems reasonable that I be able to write
counts *to* stdout (the screen) when running interactive. But
when I changed
r.write_results(show_missing=True, coverdir="/tmp")
in the doc example to just
r.write_results()
I got nothing, rather than the line-by-line count I expected. A bug?
On the other hand,
r.write_results(summary=True)
did give output - the coverage for the module, which was not helpful.
This was so with both run('func(args)') and runfunc(func, args)
Coverage should be by function, I think, especially with runfunc.
- mult-threaded programs going to multiple output handles,
especially in light of the above
- fully qualified python modules in path: (eg:
/path/to/module/my_module.py(1): print "HERE"
instead of
my_module.py(1): print "HERE".
I think a full name in the modulename line would be good, but full names
in the trace lines would be awful. In fact, I would prefer no name,
and, especially when using runfunc, line numbers relative to the
function rather than the module. Also remove the silly indent. So I
would like
--- modulename: compare, funcname: lt_iw
compare.py(47): while m != 0 and n != 0:
compare.py(48): m, n = m-1, n-1
changed to
Modulename: path/compare, funcname: lt_iw
1: while m != 0 and n != 0:
2: m, n = m-1, n-1
Ultimately, I'd like to be able to look at two runs of a program
and be able to pinpoint the very first difference
between thembased on the output of their trace runs. As it
stands, I really can't do this.
When I trace a function mentally, to write or debug, I keep track of the
values of the local names. Perhaps trace was not meant for this.
However, if I were modifying trace, the first thing I would add would be
the ability to print variable values with each line executed.
Of course I could implement the above, but I was
hoping to avoid duplicated effort if someone has
already implemented options like this..I posted the above to
the python-dev list, they suggested I take it here, so any help
would be appreciated.
I searched http://pypi.python.org/pypi for 'trace' and did not see
anything obvious. If you do modify trace and your changes are not
immediately accepted, you could list your version on PyPI. In fact,
that might be the best way to get them in. Of course, one problem you
can see from the above is that different people will have different
ideas on what constitutes 'better' ;-).
Terry Jan Reedy
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