Debugger console prints the key when the key doesn't exist in a dict

Environment data

VS Code version: 1.19.3 Python Extension version: 0.9.1 Python Version: 2.7.12 OS and version: Ubuntu 16.04.3 x64

Actual behavior

The debugger console gives a weird result when indexing a dict with a key that doesn’t exist in the dict. It prints the key… which is confusing and unexpected.

Expected behavior

It prints that the key doesn’t exist. (KeyError)

Steps to reproduce:

• Debug a file that has a dict, for example:

a = {'a': 123}

• Type in the debugger console:

>>> a['a']
123
>>> a['b']
'b' # ???

GIF

[brettcannon]

Thanks, @elliott-beach for verifying!

[DonJayamanne]

Do you know off the top of your head if you can get richer error messages from PTVSD?

This feature is currently not supported, some work was done to add support for this PythonProcessCallbackHandler.ts#L273, but was never comlpeted.

I believe this can be done.

I think this is an issue with the way the debugger handles exceptions.

As a first step, I’d saw we need to ensure the error message (b) is being handled and displayed. Then we can look at supporting rich exceptions.

Oh yes, thanks for identifying the issue in the code.