Fix "Internal error ... local variable 'errstr' referenced before assignment during BoundFunction(...)"

[jalsti]

In cc673c1 a change had been introduced in numba/core/types/functions.py:399 which includes two problems that can occur (only) when config.DEVELOPER_MODE is active:

• it uses the errstr variable before assignment
• it does not use the real function call to _bt_as_lines(bt)

This pull request fixes both problems.

[esc]

@jalsti thanks for submitting this, I have queued it for review.

[esc]

@jalsti could you potentially add the code and configuration you used to trigger it? Maybe that can form the basis of a test?

[jalsti]

Minimal example would be to set developer mode, start ipython:

$ export NUMBA_DEVELOPER_MODE=1
$ ipython3

and use following snippet, which triggers the problem here (with Numba 0.50.0 and 0.50.1)

import numba 
@numba.jit("int64[:,:,::1](int64[:,:,::1])") 
def trigger_5952(rgb): 
    foo = rgb.max(-1)

(Normally the parameter going into the function was here an RGB image as Numpy array, but the above seems enough to trigger the problem.)

[stuartarchibald]

Thanks for the example. I've made this into a test here: stuartarchibald@3523ea5, I think with this applied, the above patch can be accepted as it demonstrably fixes the issue. Many thanks for reporting this and for supplying a fix!

[jalsti]

Thank you very much.

[stuartarchibald]

@jalsti no problem, thank you for helping with this! I've applied 3523ea5 to this branch. @esc please could you verify and approve as you see fit, thanks.

[esc]

I tried this locally, and can confirm the tests to check that the patch fixes the bug, it LGTM.

[stuartarchibald]

Thanks @esc