Hi,
I think I have discovered two bugs with the inspect module and I would
like to know if anyone can spot any traps in my workaround.
I needed a function which takes a function or method and returns the
code inside it (it also adjusts the indent because I have to paste the
to a text string without indents, which is parsed later...long story).
At first this seemed trivial but then I started getting an error on
line 510 of inspect.py:
504 if iscode(object):
505 if not hasattr(object, 'co_firstlineno'):
506 raise IOError('could not find function definition')
507 lnum = object.co_firstlineno - 1
508 pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^
(\s*@)')
509 while lnum > 0:
510 if pat.match(lines[lnum]): break
511 lnum = lnum - 1
512 return lines, lnum
I finally figured out that there was a caching problem. The function I
passed was changed, but the code lines (strings) retrieved by
linecache.getlines() (on lines 464 and 466) didn't update with the new
module contents. The resulting error I was getting occurred when real
module had less lines than the cached module (or the other way around,
whatever.)
To get around this, I invoke linecache.clearcache(). Here is the
function (minus doc strings)...
INDENT_SPACES = 4
def get_fn_contents(fn, remove_indents=1):
# Clear the cache so inspect.getsourcelines doesn't try to
# check an older version of the function's module.
linecache.clearcache()
source_lines, n = inspect.getsourcelines(fn)
# Skip the first line which contains the function definition.
# Only want the code inside the function is needed.
fn_contents = source_lines[1:]
# Remove indents
new_indent_lines = [remove_indent(line, remove_indents) for line
in fn_contents]
return "".join(new_indent_lines)
def remove_indent(in_str, num_indent=1):
s = in_str
for i in range(num_indent):
if s[:INDENT_SPACES] == " ": # Whitespace indents
s = s[INDENT_SPACES:]
elif s[:1] == "\t": # Tab characters indents
s = s[1:]
return s
[END CODE]
The second issue is that the last line in the passed function's module
seems to be ignored. So, if the last line of the module is also the
last line of the function, the function is returned one line too
short.
I welcome comments on the bugs or optimization pointers for my code. I
am still quite new to Python. My primary question though is: will
linecache.clearcache() cause me any problems?
Thanks,
- Rafe
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