pdbcolor 0.5.0

A simple package to add code highlighting to the python debugger (PDB).

PDB Color

Add some color to the python debugger.

Using PDB:

Using PDB Color:

Installation

Install with pip.

pip install pdbcolor

Setup

To use PDB Color, you must set the PYTHONBREAKPOINT environment variable to pdbcolor.set_trace. You can do this by setting PYTHONBREAKPOINT before your python command. For example:

PYTHONBREAKPOINT=pdbcolor.set_trace python3 main.py

For convenience, add an alias for the prefix above to your terminal configuration file (e.g. .bashrc or .zshrc). For example:

alias pdc='PYTHONBREAKPOINT=pdbcolor.set_trace'

This allows you to use PDB Color as follows:

pdc python3 main.py

You can avoid the prefix entirely by setting the PYTHONBREAKPOINT variable in every terminal session. You can do this in your .bashrc with the following:

export PYTHONBREAKPOINT=pdbcolor.set_trace

This can cause unusual behaviour especially when working with pytest, so it is generally recommended to use the pdc alias.

Autocomplete

PDB Color also has autocompletion by default which can be triggered using the TAB key. For example:

$ python3 main.py
> /home/alex/documents/pdbcolor/main.py(9)<module>()
-> y = 2
(Pdb) str.
str.capitalize(    str.isalpha(       str.ljust(         str.rpartition(
str.casefold(      str.isascii(       str.lower(         str.rsplit(
str.center(        str.isdecimal(     str.lstrip(        str.rstrip(
str.count(         str.isdigit(       str.maketrans(     str.split(
str.encode(        str.isidentifier(  str.mro()          str.splitlines(
str.endswith(      str.islower(       str.partition(     str.startswith(
str.expandtabs(    str.isnumeric(     str.removeprefix(  str.strip(
str.find(          str.isprintable(   str.removesuffix(  str.swapcase(
str.format(        str.isspace(       str.replace(       str.title(
str.format_map(    str.istitle(       str.rfind(         str.translate(
str.index(         str.isupper(       str.rindex(        str.upper(
str.isalnum(       str.join(          str.rjust(         str.zfill(
(Pdb) str.

Docstring Shorthand

Add ? to the end of your expressions to get the docstring for your object. For example, "hello.upper?" gets the docstring for the upper function:

(Pdb) "hello".upper?
Return a copy of the string converted to uppercase.

Take care to be precise where you use ?. For example, using "hello".upper()? produces a different docstring:

(Pdb) "hello".upper()?
str(object='') -> str
str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or
errors is specified, then the object must expose a data buffer
that will be decoded using the given encoding and error handler.
Otherwise, returns the result of object.__str__() (if defined)
or repr(object).
encoding defaults to 'utf-8'.
errors defaults to 'strict'.

This is the docstring for a string object because "hello".upper() evaluates to a string. You get the same docstring using "hello"?:

(Pdb) "hello"?
str(object='') -> str
str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or
errors is specified, then the object must expose a data buffer
that will be decoded using the given encoding and error handler.
Otherwise, returns the result of object.__str__() (if defined)
or repr(object).
encoding defaults to 'utf-8'.
errors defaults to 'strict'.

Post-mortem debugging

PDB can can be triggered post-mortem (after an exception has been raised) with the following command:

python3 -m pdb -c continue main.py

PDB Color can be used instead by replacing pdb with pdbcolor.

python3 -m pdbcolor -c continue main.py

Pytest

To use PDB Color with pytest, use --pdbcls=pdbcolor:PdbColor. For example:

python3 -m pytest --pdbcls=pdbcolor:PdbColor

This drops you into PDB Color when a breakpoint is reached.

If you get a pytest OS error such as:

OSError: pytest: reading from stdin while output is captured!  Consider using `-s`.

Using the -s flag stops the error but, for those interested, the error is usually caused by setting PYTHONBREAKPOINT=pdbcolor.set_trace. Changing this back to its default value should stop the error without needing the -s flag. For example:

PYTHONBREAKPOINT=pdb.set_trace python3 -m pytest --pdbcls=pdbcolor:PdbColor