debugger: load 'ipdb' if present

* debugger: load 'ipdb' if present

Transparently chooses between the IPython-enhanced 'ipdb' or the
standard 'pdb'.

* datasette install ipdb

---------

Co-authored-by: Simon Willison <swillison@gmail.com>

datasette/handle_exception.py

@@ -5,9 +5,13 @@ from .utils.asgi import (
 )
 from .views.base import DatasetteError
 from markupsafe import Markup
-import pdb
 import traceback
 
+try:
+    import ipdb as pdb
+except ImportError:
+    import pdb
+
 try:
     import rich
 except ImportError:

docs/contributing.rst

@@ -111,10 +111,14 @@ Debugging
 
 Any errors that occur while Datasette is running while display a stack trace on the console.
 
-You can tell Datasette to open an interactive ``pdb`` debugger session if an error occurs using the ``--pdb`` option::
+You can tell Datasette to open an interactive ``pdb`` (or ``ipdb``, if present) debugger session if an error occurs using the ``--pdb`` option::
 
     datasette --pdb fixtures.db
 
+For `ipdb <https://pypi.org/project/ipdb/>`__, first run this::
+
+    datasette install ipdb
+
 .. _contributing_formatting:
 
 Code formatting