def format_traceback(exc_info):
traceback_template = '''Traceback (most recent call last):
File "%(filename)s", line %(lineno)s, in %(name)s
%(type)s: %(message)s\n''' # Skipping the "actual line" item
# Also note: we don't walk all the way through the frame stack in this example
# see hg.python.org/cpython/file/8dffb76faacc/Lib/traceback.py#l280
# (Imagine if the 1/0, below, were replaced by a call to test() which did 1/0.)
exc_type, exc_value, exc_traceback = exc_info # most recent (if any) by default
'''
Reason this _can_ be bad: If an (unhandled) exception happens AFTER this,
or if we do not delete the labels on (not much) older versions of Py, the
reference we created can linger.
traceback.format_exc/print_exc do this very thing, BUT note this creates a
temp scope within the function.
'''
traceback_details = {
'filename': exc_traceback.tb_frame.f_code.co_filename,
'lineno' : exc_traceback.tb_lineno,
'name' : exc_traceback.tb_frame.f_code.co_name,
'type' : exc_type.__name__,
'message' : exc_value.message, # or see traceback._some_str()
}
del(exc_type, exc_value, exc_traceback) # So we don't leave our local labels/objects dangling
# This still isn't "completely safe", though!
# "Best (recommended) practice: replace all exc_type, exc_value, exc_traceback
# with sys.exc_info()[0], sys.exc_info()[1], sys.exc_info()[2]
return "\n" + traceback.format_exc() + "\n\n" + traceback_template % traceback_details + "\n\n"
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