How can I make ipdb show more lines of context while debugging?

By default, during debugging in IPython, ipdb shows one line above and one line below the current position in code.

Is there an easy way to make the area shown a bit bigger? I'd think it would be configurable, but haven't been able to find it.

Solution 1:

You can type l in ipdb to show a few more lines of the current context

and you can keep hitting l and it continue revealing more lines from the file

If you want to show more lines of context around the current line you can type l to get the current line. And then type l curr_line - 10, curr_line + 10. Say I was on line 50 and I wanted to see the surrounding 20 lines. I would type: l 40,60 to see more.

As noted by @jrieke in a comment, you can also hit ll to get a bigger chunk of context. One nice thing about ll is it will print all the way back from the start of the current method (whereas consecutive ls reveal further lines below your breakpoint).

Solution 2:

You can get more context by doing:

ipdb.set_trace(context=21)

Permanent context size

To permanently set context size, find the installation directory by doing

python -c 'import ipdb; print(ipdb)'

which will show you a __init__.py file. Open that file and find the line (which may also be found in IPDB's __main__.py:

def set_trace(frame=None, context=3):

change the 3 to however many context lines you want.

Solution 3:

easy way to do this - 2022

figure out where you're loading ipdb from
import ipdb
print(ipdb.__file__)
open __main__.py from that folder
search for except (configparser.NoSectionError, configparser.NoOptionError):
below it is 3. Change that to your desired value

Why this is better than the proper way:

I don't need to learn a new configuration language
I don't need to create a new configfile
I don't need to debug why my configfile isn't being picked up
you never get tricked by file scoping/permissions/visibility since you are sure which ipdb module is being loaded (i.e. it covers virtualenvs too)
I don't have to talk to upstream and try to convince them to adopt this default.

Solution 4:

Starting with IPython 7.21 you can use context command in ipdb to change the number of backtrace lines shown:

import ipdb; ipdb.set_trace()
...
ipdb> context 10
ipdb> bt

Screenshot of IPDB after the context command has been used

You can put the following line in ~/.ipdb to make ipdb set it automatically:

context = 10

Apart from that, there's also the old context= argument in set_trace(), which makes it possible to set it at the time of running the debugger:

import ipdb; ipdb.set_trace(context=10)
# or, if you've set PYTHONBREAKPOINT=ipdb.set_trace in your environment
breakpoint(context=10)

Solution 5:

Edit: it was implemented: https://stackoverflow.com/a/66474153/895245

As a quick complement to this other answer this is the one liner that you generally want to add to the code you want to debug:

__import__('ipdb').set_trace(context=21)

You likely want to add a shortcut for that from your editor, e.g. for Vim snipmat I have:

snippet ipd
    __import__('ipdb').set_trace(context=21)

so I can type just ipd<tab> and it expands to the breakpoint. Then removing it is easy with dd since everything is contained in a single line.

Feature request for ipdb to increase the default context size: https://github.com/gotcha/ipdb/issues/147