What is the type of traceback objects in Python?

Question

import sys

try:
    raise Exception('foobar')
except:
    info = sys.exc_info()

print(type(e[2])) # <class 'traceback'>
help(traceback) # NameError: name 'traceback' is not defined

What exactly is the type of the traceback objects that Python uses for exception reporting?

The docs on sys.exc_info mention the Reference Manual, but while I've found plenty of information on how to manipulate traceback instances, I want to be able to access the type (class) itself.

Just because there is a class wiht the __name__ == 'traceback' doesn't mean that in the global namespace, traceback refers to that class. — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Jul 26, 2017 at 21:38
What are you even planning to do with this type? Having access to the type object doesn't get you much. — user2357112
– user2357112, Commented Jul 26, 2017 at 21:45
You're already accessing the type with type(e[2]), by the way. — user2357112
– user2357112, Commented Jul 26, 2017 at 21:46

Ashwini Chaudhary · Accepted Answer · 2019-06-29 13:08:45Z

38

traceback object is an instance of TracebackType present under types module.

types.TracebackType

The type of traceback objects such as found in sys.exc_info()[2].

>>> from types import TracebackType    
>>> isinstance(info[2], TracebackType)
True    
>>> TracebackType
<class 'traceback'>

As pointed out by @user2357112 the name TracebackType is basically an alias to the internal traceback type and is set by raising an exception in types module. The actual traceback type can be found in CPython code.

edited Jun 29, 2019 at 13:08

answered Jul 26, 2017 at 21:40

Ashwini Chaudhary

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3 Comments

user2357112 Over a year ago

It should be noted that this isn't the "true" name of the type - there's no "true" name - and it's not the place where the type is defined. types.py just raises an exception to get the traceback and sets TracebackType = type(tb).

Ashwini Chaudhary Over a year ago

@user2357112 Updated.

Lenormju Over a year ago

Available in Python >= 3.10

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