Strange AttributeError on grid edit

[jcrm...@gmail.com]

Hello,

I have this grid:

    grid = SQLFORM.grid(
        query,
        create=create,
        csv=False,
        deletable=deletable,
        details=False,
        editable=editable,
        # Disable delete checkbox in edit form.
        editargs=dict(deletable=False),
        field_id=db.equipment.id,
        fields=fields,
        headers={'sn_counter.name': T('SN counter')},
        links=[
            lambda row: A(
                T('Pow. supp.'),
                _href=URL(
                    'single_equip',
                    'set_session_vars',
                    args=[row.equipment.id],
                    vars={
                        'table_name': 'equip_ps',
                        'parent_id_field_name': 'ps_id',
                        'parent_table_name': 'power_supply',
                        # Only sid because next page has search
                        # (which uses vars).
                        'sid': request.vars.sid,
                    },
                ),
                _id='power_supply',
            ),

...

Definitions above the grid are

query = db.equipment.sn_counter_id == db.sn_counter.id

create, deletable and editable are True/False according to the user permissions.

ondelete and onvalidation are a function/None according to the user permissions.

The links on the grid work fine, new record works fine, but edit returns a strange AttributeError.

I was able to identify the problem has been the args argument.

If I change

args=[row.equipment.id],

with

args=[str(row).split("'id': ")[1].split('},')[0]],

everything works, including edit. What I'm doing is extracting the id from the string converted row.

I have no idea why this strange error occurs.

Any ideas?

The complete traceback:

ERROR:web2py:Traceback (most recent call last):
  File "c:\web2py\gluon\restricted.py", line 219, in restricted
    exec(ccode, environment)
  File "c:\web2py\applications\ajc\controllers/equipment.py", line 398, in <modu
le>
  File "c:\web2py\gluon\globals.py", line 421, in <lambda>
    self._caller = lambda f: f()
  File "c:\web2py\gluon\tools.py", line 3877, in f
    return action(*a, **b)
  File "c:\web2py\applications\ajc\controllers/equipment.py", line 341, in index

    user_signature=False,
  File "c:\web2py\gluon\sqlhtml.py", line 2610, in grid
    res = DIV(buttons(view=details, record=record),
  File "c:\web2py\gluon\sqlhtml.py", line 2532, in buttons
    elif link(record):
  File "c:\web2py\applications\ajc\controllers/equipment.py", line 236, in <lamb
da>
    args=[row.equipment.id],
  File "c:\web2py\gluon\packages\dal\pydal\objects.py", line 116, in __getattr__

    return self.__getitem__(k)
  File "c:\web2py\gluon\packages\dal\pydal\objects.py", line 100, in __getitem__

    v = self[key] = lg(key)
  File "c:\web2py\gluon\packages\dal\pydal\objects.py", line 2490, in __call__
    raise AttributeError()
AttributeError

My env:

web2py 2.18.5

Python 3.7.1 x86

Firefox 66.0.3 x64

Windows 7 Pro x64 SP1+all upd

Thanks,

JM