Contrasting Python default stack trace vs Glom data trace

glom_post_data_trace.py

# python 3.10 with glom 23
>>> import glom
>>> target = {'planets': [{'name': 'earth', 'moons': 1}]}
>>> spec = ('planets', ['rings'])  # a spec we expect to fail
>>> glom.glom(target, spec)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/mahmoud/projects/glom/glom/core.py", line 2297, in glom
    raise err
glom.core.PathAccessError: error raised while processing, details below.
 Target-spec trace (most recent last):
 - Target: {'planets': [{'moons': 1, 'name': 'earth'}]}
 - Spec: ('planets', ['rings'])
 - Spec: 'planets'
 - Target: [{'moons': 1, 'name': 'earth'}]
 - Spec: ['rings']
 - Target: {'moons': 1, 'name': 'earth'}
 - Spec: 'rings'
glom.core.PathAccessError: could not access 'rings', part 0 of Path('rings'), got error: KeyError('rings')

glom_pre_data_trace.py

# python 3.10 with glom==20.5.0
>>> import glom
>>> target = {'planets': [{'name': 'earth', 'moons': 1}]}
>>> spec = ('planets', ['rings'])  # a spec we expect to fail
>>> glom.glom(target, spec)
Traceback (most recent call last):
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1204, in _t_eval
    cur = get(cur, arg)
KeyError: 'rings'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1819, in glom
    ret = _glom(target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1840, in _glom
    return scope[MODE](target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1849, in AUTO
    return _handle_tuple(target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1549, in _handle_tuple
    nxt = scope[glom](res, subspec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1840, in _glom
    return scope[MODE](target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1847, in AUTO
    return _handle_list(target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1537, in _handle_list
    val = scope[glom](t, subspec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1840, in _glom
    return scope[MODE](target, spec, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1851, in AUTO
    return Path.from_text(spec).glomit(target, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 373, in glomit
    return _t_eval(target, self.path_t, scope)
  File "/home/mahmoud/projects/glom/tmpvenv/lib/python3.10/site-packages/glom/core.py", line 1206, in _t_eval
    raise PathAccessError(e, Path(_t), i // 2)
glom.core.PathAccessError: could not access 'rings', part 0 of Path('rings'), got error: KeyError('rings')