REGR: frame/frame op with unaligned blocks + non-slice-like placement failing with assertion error

[jorisvandenbossche]

In [7]: arr = np.random.randint(0, 1000, (100, 10))  

In [8]: df1 = pd.DataFrame(arr)  

In [9]: df2 = df1.copy() 
   ...: df2.iloc[0, [1, 3, 7]] =  np.nan    

In [10]: df1 + df2  
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
<ipython-input-10-fa4784095cc3> in <module>
----> 1 df1 + df2

~/scipy/pandas/pandas/core/ops/__init__.py in f(self, other, axis, level, fill_value)
    663         if isinstance(other, ABCDataFrame):
    664             # Another DataFrame
--> 665             new_data = self._combine_frame(other, na_op, fill_value)
    666 
    667         elif isinstance(other, ABCSeries):

~/scipy/pandas/pandas/core/frame.py in _combine_frame(self, other, func, fill_value)
   5734                 return func(left, right)
   5735 
-> 5736         new_data = ops.dispatch_to_series(self, other, _arith_op)
   5737         return new_data
   5738 

~/scipy/pandas/pandas/core/ops/__init__.py in dispatch_to_series(left, right, func, axis)
    283 
    284         array_op = get_array_op(func)
--> 285         bm = left._mgr.operate_blockwise(right._mgr, array_op)
    286         return type(left)(bm)
    287 

~/scipy/pandas/pandas/core/internals/managers.py in operate_blockwise(self, other, array_op)
    358         Apply array_op blockwise with another (aligned) BlockManager.
    359         """
--> 360         return operate_blockwise(self, other, array_op)
    361 
    362     def apply(self: T, f, align_keys=None, **kwargs) -> T:

~/scipy/pandas/pandas/core/internals/ops.py in operate_blockwise(left, right, array_op)
     34             right_ea = not isinstance(rblk.values, np.ndarray)
     35 
---> 36             lvals, rvals = _get_same_shape_values(blk, rblk, left_ea, right_ea)
     37 
     38             res_values = array_op(lvals, rvals)

~/scipy/pandas/pandas/core/internals/ops.py in _get_same_shape_values(lblk, rblk, left_ea, right_ea)
     84 
     85     # Require that the indexing into lvals be slice-like
---> 86     assert rblk.mgr_locs.is_slice_like, rblk.mgr_locs
     87 
     88     # TODO(EA2D): with 2D EAs pnly this first clause would be needed

AssertionError: BlockPlacement([0 2 4 5 6 8 9])

cc @jbrockmendel I suppose caused by the frame-frame blockwise PR (#32779), but didn't yet look into detail

Just removing the assertion seems to still work (for this case), but I don't know if that _get_same_shape_values functino relies on the is_slice_like characteristic for its implementation to be correct

[jorisvandenbossche]

And another assertion error with a slightly different case (left and right not exactly the same):

In [11]: df2 = df1.copy() 
    ...: df2.iloc[0, [1, 3, 7]] =  np.nan 

In [12]: df3 = df1.copy() 
    ...: df3.iloc[0, [5]] =  np.nan

In [13]: df2 + df3  
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
<ipython-input-13-f31d5cc84129> in <module>
----> 1 df2 + df3

~/scipy/pandas/pandas/core/ops/__init__.py in f(self, other, axis, level, fill_value)
    663             axis = self._get_axis_number(axis) if axis is not None else 1
    664             new_data = _combine_series_frame(self, other, op, axis=axis)
--> 665         else:
    666             # in this case we always have `np.ndim(other) == 0`
    667             if fill_value is not None:

~/scipy/pandas/pandas/core/frame.py in _combine_frame(self, other, func, fill_value)
   5734         result = self.copy()
   5735 
-> 5736         if axis == 0:
   5737             assert isinstance(result.index, MultiIndex)
   5738             result.index = result.index.reorder_levels(order)

~/scipy/pandas/pandas/core/ops/__init__.py in dispatch_to_series(left, right, func, axis)
    283     elif isinstance(right, ABCSeries) and axis == "columns":
    284         # We only get here if called via _combine_series_frame,
--> 285         # in which case we specifically want to operate row-by-row
    286         assert right.index.equals(left.columns)
    287 

~/scipy/pandas/pandas/core/internals/managers.py in operate_blockwise(self, other, array_op)
    358 
    359             if np.ndim(bres) == 0:
--> 360                 # EA
    361                 assert blk.shape[0] == 1
    362                 new_res = zip(blk.mgr_locs.as_array, [bres])

~/scipy/pandas/pandas/core/internals/ops.py in operate_blockwise(left, right, array_op)
     23         left_ea = not isinstance(blk_vals, np.ndarray)
     24 
---> 25         rblks = right._slice_take_blocks_ax0(locs.indexer, only_slice=True)
     26 
     27         # Assertions are disabled for performance, but should hold:

~/scipy/pandas/pandas/core/internals/managers.py in _slice_take_blocks_ax0(self, slice_or_indexer, fill_value, only_slice)
   1383                     # A non-consolidatable block, it's easy, because there's
   1384                     # only one item and each mgr loc is a copy of that single
-> 1385                     # item.
   1386                     for mgr_loc in mgr_locs:
   1387                         newblk = blk.copy(deep=False)

~/scipy/pandas/pandas/core/internals/blocks.py in getitem_block(self, slicer, new_mgr_locs)
    297             raise ValueError("Only same dim slicing is allowed")
    298 
--> 299         return self.make_block_same_class(new_values, new_mgr_locs)
    300 
    301     @property

~/scipy/pandas/pandas/core/internals/blocks.py in make_block_same_class(self, values, placement, ndim)
    252         if ndim is None:
    253             ndim = self.ndim
--> 254         return type(self)(values, placement=placement, ndim=ndim)
    255 
    256     def __repr__(self) -> str:

~/scipy/pandas/pandas/core/internals/blocks.py in __init__(self, values, placement, ndim)
    112     def __init__(self, values, placement, ndim=None):
    113         self.ndim = self._check_ndim(values, ndim)
--> 114         self.mgr_locs = placement
    115         self.values = values
    116 

~/scipy/pandas/pandas/core/internals/blocks.py in mgr_locs(self, new_mgr_locs)
    230     def mgr_locs(self, new_mgr_locs):
    231         if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
--> 232             new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
    233 
    234         self._mgr_locs = new_mgr_locs

~/scipy/pandas/pandas/_libs/internals.pyx in pandas._libs.internals.BlockPlacement.__init__()

AssertionError: ()

[jbrockmendel]

im having hardware issues, wont be able to troubleshoot this for a few days