How can I modify a Python traceback object when raising an exception?

Question

I\'m working on a Python library used by third-party developers to write extensions for our core application.

I\'d like to know if it\'s possible to modify the trace

Answer 1

This code might be of interest for you.

It takes a traceback and removes the first file, which should not be shown. Then it simulates the Python behavior:

Traceback (most recent call last):

will only be shown if the traceback contains more than one file. This looks exactly as if my extra frame was not there.

Here my code, assuming there is a string text:

try:
    exec(text)
except:
    # we want to format the exception as if no frame was on top.
    exp, val, tb = sys.exc_info()
    listing = traceback.format_exception(exp, val, tb)
    # remove the entry for the first frame
    del listing[1]
    files = [line for line in listing if line.startswith("  File")]
    if len(files) == 1:
        # only one file, remove the header.
        del listing[0]
    print("".join(listing), file=sys.stderr)
    sys.exit(1)