BUG: Ensure .astype doesn't use PandasArray

[TomAugspurger]

On 0.24.0rc1, it's possible to end up with a PandasArray in internals.

In [8]: ser = pd.Series([1, 2])

In [9]: ser.astype(ser.array.dtype)._data.blocks[0]
Out[9]: ExtensionBlock: 2 dtype: int64

[TomAugspurger]

Subclasses overriding Block._astype get the sanitized version as well, which is arguably what we want.

…

On Mon, Jan 21, 2019 at 3:04 PM Jeff Reback ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In pandas/core/internals/blocks.py <#24866 (comment)>: > @@ -530,6 +530,10 @@ def f(m, v, i): return self.split_and_operate(None, f, False) def astype(self, dtype, copy=False, errors='raise', values=None, **kwargs): + dtype = pandas_dtype(dtype) i don’t want to put this clause where the existing is? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#24866 (review)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABQHIqfSCJx3q0PFLshrku91aZL-rkdwks5vFit2gaJpZM4aLZlp> .

[codecov]

Codecov Report

Merging #24866 into master will decrease coverage by 49.5%.
The diff coverage is 66.66%.

@@             Coverage Diff             @@
##           master   #24866       +/-   ##
===========================================
- Coverage   92.39%   42.88%   -49.51%     
===========================================
  Files         166      166               
  Lines       52412    52414        +2     
===========================================
- Hits        48424    22479    -25945     
- Misses       3988    29935    +25947

Flag	Coverage Δ
#multiple	?
#single	42.88% <66.66%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/internals/blocks.py	52.25% <66.66%> (-42.01%)	⬇️
pandas/io/formats/latex.py	0% <0%> (-100%)	⬇️
pandas/core/categorical.py	0% <0%> (-100%)	⬇️
pandas/io/sas/sas_constants.py	0% <0%> (-100%)	⬇️
pandas/tseries/plotting.py	0% <0%> (-100%)	⬇️
pandas/tseries/converter.py	0% <0%> (-100%)	⬇️
pandas/io/formats/html.py	0% <0%> (-99.35%)	⬇️
pandas/core/groupby/categorical.py	0% <0%> (-95.46%)	⬇️
pandas/io/sas/sas7bdat.py	0% <0%> (-91.17%)	⬇️
pandas/io/sas/sas_xport.py	0% <0%> (-90.15%)	⬇️
... and 124 more

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[codecov]

Codecov Report

Merging #24866 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #24866      +/-   ##
==========================================
- Coverage   91.98%   91.97%   -0.02%     
==========================================
  Files         175      175              
  Lines       52372    52369       -3     
==========================================
- Hits        48172    48164       -8     
- Misses       4200     4205       +5

Flag	Coverage Δ
#multiple	90.52% <100%> (-0.01%)	⬇️
#single	40.69% <50%> (-0.15%)	⬇️

Impacted Files	Coverage Δ
pandas/core/internals/blocks.py	94.07% <100%> (-0.02%)	⬇️
pandas/io/gbq.py	78.94% <0%> (-10.53%)	⬇️
pandas/core/frame.py	96.9% <0%> (-0.12%)	⬇️
pandas/util/testing.py	90.61% <0%> (-0.11%)	⬇️

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[TomAugspurger]

I believe that this is unnecessary now... The .astype should get us an array of the correct type, and from there we'll get the correct block in make_block.

[TomAugspurger]

All green.

I'm a bit concerned that this is the wrong place to fix the issue. We could alternatively put this check in make_block so that if a PandasArray or PandasDtype is there, the the array / dtype is converted to a NumPy version before proceeding...

[TomAugspurger]

Trying to move it to make_block.

[jreback]

needs a retest, can you merge master

[jreback]

merged master; lets see

[jreback]

thanks @TomAugspurger