To help you get started, we've collected the most common ways that ipdb is being used within popular public projects.

IPython pdb

Use

ipdb exports functions to access the IPython debugger, which features tab completion, syntax highlighting, better tracebacks, better introspection with the same interface as the pdb module.

Example usage:

import ipdb
ipdb.set_trace()
ipdb.set_trace(context=5)  # will show five lines of code
                           # instead of the default three lines
                           # or you can set it via IPDB_CONTEXT_SIZE env variable
                           # or setup.cfg file
ipdb.pm()
ipdb.run('x[0] = 3')
result = ipdb.runcall(function, arg0, arg1, kwarg='foo')
result = ipdb.runeval('f(1,2) - 3')

Arguments for set_trace

The set_trace function accepts context which will show as many lines of code as defined, and cond, which accepts boolean values (such as abc == 17) and will start ipdb's interface whenever cond equals to True.

Using configuration file

It's possible to set up context using a .ipdb file on your home folder, setup.cfg or pyproject.toml on your project folder. You can also set your file location via env var $IPDB_CONFIG. Your environment variable has priority over the home configuration file, which in turn has priority over the setup config file. Currently, only context setting is available.

A valid setup.cfg is as follows

[ipdb]
context=5

A valid .ipdb is as follows

context=5

A valid pyproject.toml is as follows

[tool.ipdb]
context=5

The post-mortem function, ipdb.pm(), is equivalent to the magic function %debug.

If you install ipdb with a tool which supports setuptools entry points, an ipdb script is made for you. You can use it to debug your python 2 scripts like

$ bin/ipdb mymodule.py

And for python 3

$ bin/ipdb3 mymodule.py

Alternatively with Python 2.7 only, you can also use

$ python -m ipdb mymodule.py

You can also enclose code with the with statement to launch ipdb if an exception is raised:

from ipdb import launch_ipdb_on_exception

with launch_ipdb_on_exception():
    [...]

Or you can use iex as a function decorator to launch ipdb if an exception is raised:

from ipdb import iex

@iex
def main():
    [...]

Issues with stdout

Some tools, like nose fiddle with stdout.

Until ipdb==0.9.4, we tried to guess when we should also fiddle with stdout to support those tools. However, all strategies tried until 0.9.4 have proven brittle.

If you use nose or another tool that fiddles with stdout, you should explicitly ask for stdout fiddling by using ipdb like this

import ipdb
ipdb.sset_trace()
ipdb.spm()

from ipdb import slaunch_ipdb_on_exception
with slaunch_ipdb_on_exception():
    [...]

Development

ipdb source code and tracker are at .

Pull requests should take care of updating the changelog HISTORY.txt.

Under the unreleased section, add your changes and your username.

Manual testing

To test your changes, make use of manual_test.py. Create a virtual environment, install IPython and run python manual_test.py and check if your changes are in effect. If possible, create automated tests for better behaviour control.

Automated testing

To run automated tests locally, create a virtual environment, install coverage and run coverage run setup.py test.

Third-party support

Products.PDBDebugMode

Zope2 Products.PDBDebugMode uses ipdb, if available, in place of pdb.

iw.debug

iw.debug allows you to trigger an ipdb debugger on any published object of a Zope2 application.

ipdbplugin

ipdbplugin is a nose test runner plugin that also uses the IPython debugger instead of pdb. (It does not depend on ipdb anymore).

Changelog

0.13.13 (2023-03-09)

• Use context manager for opening toml config [andrewzwicky]

0.13.12 (2023-03-09)

• Modify tests to test 3.11 separately from earlier python versions. [andrewzwicky]

0.13.11 (2022-12-13)

• Better exception handling when looking for config. [bignose-debian]

0.13.10 (2022-12-13)

• Better toml support (use tomlib for 3.11, tomli for 3.6 to 3.10). [salty-horse, mgorny]
• Minimal PEP 517 support. [cpcloud]
• 3.11 support for run as module and run as script. [nphilipp, gotcha]
• Based on OSV:PYSEC-2022-12 change ipython dependencies, for users using python 3.6, install 7.16.3 <= IPython < 7.17.0, for users using python>3.6, install IPython >= 7.31.1. [malkstar]

0.13.9 (2021-06-02)

• Fix again when pyproject.toml does not contain tool section. [markab108]

0.13.8 (2021-05-26)

• Fix when pyproject.toml does not contain tool section. [anjos]
• Add the convenience function iex(). [alanbernstein]

0.13.7 (2021-03-16)

• Do not instantiate IPython on import [adamchainz]

0.13.6 (2021-03-08)

• Fix broken parsing of pyproject.toml [alexandrebarbaruiva]

0.13.5 (2021-03-02)

• Add support for pyproject.toml as configuration file [alexandrebarbaruiva]
• For users using python 3.4, install 6.0.0 <= IPython < 7.0.0, for users using python 3.5, install 7.0.0 <= IPython < 7.10.0, for users using python 3.6, install 7.10.0 <= IPython < 7.17.0, for users using python>3.6, install IPython >= 7.17.0. [d1618033]

0.13.4 (2020-10-01)

• Add '-m' option [mrmino]

0.13.3 (2020-06-23)

• Allow runcall, runeval to also use set context value [meowser]
• Add condition argument to set_trace [alexandrebarbaruiva]

0.13.2 (2020-03-03)

• Remove leftover debug code [gotcha]

0.13.1 (2020-02-28)

• Fix when no configuration file [gotcha]

0.13.0 (2020-02-28)

• Add option to set context via environment variable or configuration file [alexandrebarbaruiva]

0.12.3 (2019-12-03)

• Fix version in usage [gotcha]

0.12.2 (2019-07-30)

• Avoid emitting term-title bytes [steinnes]

0.12.1 (2019-07-26)

• Fix --help [native-api]

0.12 (2019-03-20)

• Drop support for Python 3.3.x [bmw]
• Stop deprecation warnings from being raised when IPython >= 5.1 is used. Support for IPython < 5.1 has been dropped. [bmw]

0.11 (2018-02-15)

• Simplify loading IPython and getting information from it. Drop support for python 2.6 Drop support for IPython < 5.0.0 [takluyver]

0.10.3 (2017-04-22)

• For users using python 2.6, do not install IPython >= 2.0.0. And for users using python 2.7, do not install IPython >= 6.0.0. [vphilippon]
• Drop support for python 3.2. [vphilippon]
• Command line usage consistent with pdb - Add argument commands [zvodd]

0.10.2 (2017-01-25)

• Ask IPython which debugger class to use. Closes [gnebehay, JBKahn]
• ipdb.set_trace() does not ignore context arg anymore. Closes . [gnebehay, Garrett-R]

0.10.1 (2016-06-14)

• Support IPython 5.0. [ngoldbaum]

0.10.0 (2016-04-29)

• Stop trying to magically guess when stdout needs to be captured. Like needed by nose. Rather, provide a set of function that can be called explicitely when needed. [gotcha]
• drop support of IPython before 0.10.2

0.9.4 (2016-04-29)

• Fix Restart error when using python -m ipdb Closes . [gotcha]

0.9.3 (2016-04-15)

• Don't require users to pass a traceback to post_mortem. [Wilfred]

0.9.2 (2016-04-15)

• Closes . [gotcha]

0.9.1 (2016-04-12)

• Reset sys.modules['__main__'] to original value. Closes [gotcha]
• Fix support of IPython versions 0.x [asivokon]

0.9.0 (2016-02-22)

• Switch to revised BSD license (with approval of all contributors). Closes [lebedov, gotcha]

0.8.3 (2016-02-17)

• Don't pass sys.argv to IPython for configuration. [emulbreh]

0.8.2 (2016-02-15)

• Fix lexical comparison for version numbers. [sas23]
• Allow configuring how many lines of code context are displayed by set_trace [JamshedVesuna]
• If an instance of IPython is already running its configuration will be loaded. [IxDay]

0.8.1 (2015-06-03)

• Make Nose support less invasive. Closes Closes [blink1073, gotcha]
• Fix for post_mortem in context manager. Closes [omergertel]

0.8 (2013-09-19)

• More Python 3 compatibility; implies dropping Python 2.5 support. Closes [gotcha]

0.7.1 (2013-09-19)

• IPython 1.0 compatibility. Closes [pgularski]
• Index into version_info in setup.py for Python 2.6 compatibility. [kynan]
• Add Travis CI configuration. [kynan]

0.7 (2012-07-06)

• Add launch_ipdb_on_exception context manager. Implies dropping Python 2.4 support. [Psycojoker]
• Wrap sys.excepthook only once. [marciomazza]
• Add GPL file and refer in headers. [stan3]
• Python 3 support. [Piet Delport]
• Basic tests. [msabramo]
• Added the functions runcall, runeval and run. [dimasad]

0.6.1 (2011-10-17)

• State dependency on IPython later or equal to 0.10. [gotcha]

0.6 (2011-09-01)

• Add setuptools console_scripts entry point. [akrito, gotcha]
• Nose support. Closes [akaihola, gotcha]

0.5 (2011-08-05)

• IPython 0.11 support. [lebedov]

0.4 (2011-06-13)

• When used from IPython, use its colors. Closes [gotcha]
• Fixed errors when exiting with "q". [gotcha]
• Allow use of python -m ipdb mymodule.py. Python 2.7 only. Closes [gotcha]
• Fixed post_mortem when the traceback is None. [maurits]

0.3 (2011-01-16)

• Add post_mortem() for Products.PDBDebugMode support. [Jean Jordaan]
• Moved to github.com.

0.2 (2010-10-20)

• Added pm(). [Paulo Benedict Ang]

0.1 (2010-04-26)

• First "non dev" release.