Error formatting text width is not padded to CPython/readline's 80chars

[stuartarchibald]

Reporting a bug

• I am using the latest released version of Numba (most recent is visible in
  the change log (https://github.com/numba/numba/blob/master/CHANGE_LOG).
• I have included below a minimal working reproducer (if you are unsure how
  to write one see http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports).

The output from Numba error rewriting should be padded to 80 chars as per the Python traceback formatting. An example of this not working:

$ python pointlesslongfilenametooverflowtermwidthsothatitisatleast80charslongthisnameis81.py|&cowsay -W80                       
 _________________________________________________________________________________                                              
/ Traceback (most recent call last):                                              \                                             
|                                                                                 |                                             
| File                                                                            |                                             
| "pointlesslongfilenametooverflowtermwidthsothatitisatleast80charslongthisnameis |                                             
| 81.py", line 13, in <module>                                                    |                                             
|                                                                                 |                                             
| print(test(rec[0]))                                                             |                                             
|                                                                                 |                                             
| File "< path                             >numba/numba/dispatcher.py", line 348, |                                             
| in _compile_for_args                                                            |                                             
|                                                                                 |                                             
| error_rewrite(e, 'typing')                                                      |                                             
|                                                                                 |                                             
| File "< path                             >numba/numba/dispatcher.py", line 313, |                                             
| in error_rewrite                                                                |                                             
|                                                                                 |                                             
| raise e                                                                         |                                             
|                                                                                 |                                             
| File "< path                             >numba/numba/dispatcher.py", line 324, |                                             
| in _compile_for_args                                                            |                                             
|                                                                                 |                                             
| return self.compile(tuple(argtypes))                                            |                                             
|                                                                                 |                                             
| File "< path                             >numba/numba/compiler_lock.py", line   |                                             
| 32, in _acquire_compile_lock                                                    |
|                                                                                 |
| return func(*args, **kwargs)                                                    |
|                                                                                 |
| File "< path                             >numba/numba/dispatcher.py", line 655, |
| in compile                                                                      |
|                                                                                 |
| cres = self._compiler.compile(args, return_type)                                |
|                                                                                 |
| File "< path                             >numba/numba/dispatcher.py", line 82,  |
| in compile                                                                      |
|                                                                                 |
| pipeline_class=self.pipeline_class)                                             |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 904,   |
| in compile_extra                                                                |
|                                                                                 |
| return pipeline.compile_extra(func)                                             |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 367,   |
| in compile_extra                                                                |
|                                                                                 |
| return self._compile_bytecode()                                                 |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 835,   |
| in _compile_bytecode                                                            |
|                                                                                 |
| return self._compile_core()                                                     |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 822,   |
| in _compile_core                                                                |
|                                                                                 |
| res = pm.run(self.status)                                                       |
|                                                                                 |
| File "< path                             >numba/numba/compiler_lock.py", line   |
| 32, in _acquire_compile_lock                                                    |
|                                                                                 |
| return func(*args, **kwargs)                                                    |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 253,   |
| in run                                                                          |
|                                                                                 |
| raise patched_exception                                                         |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 244,   |
| in run                                                                          |
|                                                                                 |
| stage()                                                                         |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 477,   |
| in stage_nopython_frontend                                                      |
|                                                                                 |
| self.locals)                                                                    |
|                                                                                 |
| File "< path                             >numba/numba/compiler.py", line 1006,  |
| in type_inference_stage                                                         |
|                                                                                 |
| infer.propagate()                                                               |
|                                                                                 |
| File "< path                             >numba/numba/typeinfer.py", line 860,  |
| in propagate                                                                    |
|                                                                                 |
| raise errors[0] numba.errors.TypingError: Failed in nopython mode pipeline      |
| (step: nopython frontend) failed to unpack Record([('index',  |
| '<i8'), ('a', '<f8'), ('b', '|b1')])  File                             |
| "pointlesslongfilenametooverflowtermwidthsothatitisatleast80charslongthisnameis |
| 81.py", line 10: def test(record):  i, a, b = record  |
| ^  [1] During: typing of exhaust iter at      |
| pointlesslongfilenametooverflowtermwidthsothatitisatleast80charslongthisnameis8 |
| 1.py (10)  File                                                    |
| "pointlesslongfilenametooverflowtermwidthsothatitisatleast80charslongthisnameis |
| 81.py", line 10: def test(record):  i, a, b = record  |
\ ^                                                              /
 ---------------------------------------------------------------------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

note the somewhat messy appearance once out of CPython traceback and into Numba error message helpers.