html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/pull/2956#issuecomment-568903698,https://api.github.com/repos/pydata/xarray/issues/2956,568903698,MDEyOklzc3VlQ29tbWVudDU2ODkwMzY5OA==,14808389,2019-12-25T14:11:45Z,2019-12-25T14:11:45Z,MEMBER,"Since we have been making a lot of progress using `__array_function__` (which does not exclude subclasses but is much more flexible), this approach is outdated and I'm closing this and #1118.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-524881974,https://api.github.com/repos/pydata/xarray/issues/2956,524881974,MDEyOklzc3VlQ29tbWVudDUyNDg4MTk3NA==,14808389,2019-08-26T14:26:34Z,2019-08-26T14:26:34Z,MEMBER,"> We could add the experimental option for allowing subclasses for testing purposes, but ultimately I think we want to insist that objects we use inside `data` implement `__array_function__`, regardless of whether they are a numpy array subclass or duck array. Otherwise there's no way complicated operations like `concat` are going to work properly.

@shoyer: What kind of testing would that be? If this is something that would be removed again in the future and has no actual value, feel free to close (but don't forget the original PR). Otherwise, I'd be happy to continue working on this.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523242520,https://api.github.com/repos/pydata/xarray/issues/2956,523242520,MDEyOklzc3VlQ29tbWVudDUyMzI0MjUyMA==,14808389,2019-08-21T00:08:53Z,2019-08-21T00:08:53Z,MEMBER,then I would like to finish this one and modify the tests in a new one.,"{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523232553,https://api.github.com/repos/pydata/xarray/issues/2956,523232553,MDEyOklzc3VlQ29tbWVudDUyMzIzMjU1Mw==,1217238,2019-08-20T23:21:42Z,2019-08-20T23:21:42Z,MEMBER,"You are welcome to continue here or in a new PR, whichever you prefer. I don't have a strong opinion, please do whichever seems easier for you.

I think the best examples of complex operations to check for compatibility can be found in `xarray/tests/test_sparse.py` and `xarray/tests/test_dask.py`","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523231052,https://api.github.com/repos/pydata/xarray/issues/2956,523231052,MDEyOklzc3VlQ29tbWVudDUyMzIzMTA1Mg==,14808389,2019-08-20T23:15:00Z,2019-08-20T23:15:00Z,MEMBER,"I think I would like to tackle this, but I definitely will need some help with finding examples for some of the more advanced operations.

@shoyer should I add these in a new PR or should I repurpose this one?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523229039,https://api.github.com/repos/pydata/xarray/issues/2956,523229039,MDEyOklzc3VlQ29tbWVudDUyMzIyOTAzOQ==,14808389,2019-08-20T23:06:27Z,2019-08-20T23:07:04Z,MEMBER,"Do you have a rough idea of which operations these tests should check? The ones currently implemented are `mean()` and an xfailing `concat`. There is also the `sel()`, but as it only tries to use values with the matching unit, it works even though it should probably fail.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523225141,https://api.github.com/repos/pydata/xarray/issues/2956,523225141,MDEyOklzc3VlQ29tbWVudDUyMzIyNTE0MQ==,1217238,2019-08-20T22:50:25Z,2019-08-20T22:50:25Z,MEMBER,"> However, the question of whether or not this PR is obsolete now still remains: if one were to replace `quantities` with `pint`, the test checking that this does not work without the proposed changes enabled is the only one that fails.

Does pint do `__array_function__` yet? It looks like the answer is ""not yet"" but there's a branch with experimental support: https://github.com/hgrecco/pint/pull/764

We could add the experimental option for allowing subclasses for testing purposes, but ultimately I think we want to insist that objects we use inside `data` implement `__array_function__`, regardless of whether they are a numpy array subclass or duck array. Otherwise there's no way complicated operations like `concat` are going to work properly.

I'd love to add tests that verify that xarray can properly wrap arrays with units as soon as possible. We could even merge tests that are all marked ""xfail"" and that currently only pass when using the experimental version of pint from https://github.com/hgrecco/pint/pull/764.

As we saw with sparse array support, this will be useful for two reasons:
1. It will help us identify remaining issues that need to be solved either in xarray or in an array-with-units library like pint.
2. There are also likely some subtle tweaks we can do inside xarray to better support arrays with units, e.g., displaying units in the `xarray.Dataset` repr.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-523183790,https://api.github.com/repos/pydata/xarray/issues/2956,523183790,MDEyOklzc3VlQ29tbWVudDUyMzE4Mzc5MA==,14808389,2019-08-20T20:35:02Z,2019-08-20T20:35:02Z,MEMBER,"I'm not too sure about putting `_asarray` into `npcompat.py`, but apart from that I would say it is ready to be merged.

However, the question of whether or not this PR is obsolete now still remains: if one were to replace `quantities` with `pint`, the test checking that this does not work without the proposed changes enabled is the only one that fails.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-520632305,https://api.github.com/repos/pydata/xarray/issues/2956,520632305,MDEyOklzc3VlQ29tbWVudDUyMDYzMjMwNQ==,14808389,2019-08-12T23:32:50Z,2019-08-12T23:32:50Z,MEMBER,"now that #3117 has been merged, what is the status on this? From what I can tell from the few I looked at, most ndarray subclasses either already use NEP18 or will do so in the future. I guess what I want to know is: should I continue to work on it or does it overlap too much with that PR?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-494163389,https://api.github.com/repos/pydata/xarray/issues/2956,494163389,MDEyOklzc3VlQ29tbWVudDQ5NDE2MzM4OQ==,2448579,2019-05-20T21:49:10Z,2019-05-20T21:49:10Z,MEMBER,Looks like a glitch related to downloading an example file. Ignore it.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-494151339,https://api.github.com/repos/pydata/xarray/issues/2956,494151339,MDEyOklzc3VlQ29tbWVudDQ5NDE1MTMzOQ==,14808389,2019-05-20T21:07:06Z,2019-05-20T21:07:06Z,MEMBER,"I added the option, though the documentation is minimal. It gets used by a function to decide between `asarray` and `asanyarray`, and this function is then called in `as_compatible_data` and in the `Variable.data` property. Also, `.mean()` did not work before because `duck_array_ops.asarray` used `np.asarray`, which I replaced with that switching function. Should I test more of these reduce functions (if so, which)?

The `matrix` class gets treated similar to `MaskedArray`, and the unittests prove that enabling subclass support does not work for these two.

Is the failure of the docs related to any of the changes I made?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-493839144,https://api.github.com/repos/pydata/xarray/issues/2956,493839144,MDEyOklzc3VlQ29tbWVudDQ5MzgzOTE0NA==,1217238,2019-05-20T04:59:16Z,2019-05-20T04:59:16Z,MEMBER,"This looks like a good start to me. So we can start making progress on this, I think it would make sense to hide this behavior behind an option, e.g., `xarray.set_options(enable_experimental_ndarray_subclass_support=True)`.

I would consider writing some tests with two of the ndarray subclasses that ship with NumPy:
- `np.matrix`
- `np.ma.MaskedArray`

Both of these subclasses violate some important principles of subclassing, namely they aren't substitutable with objects of their parent class. Thus, I think it would be reasonable to explicitly ""blacklist"" them for use inside in xarray.DataArray. I think we already explicitly convert MaskedArray objects, but perhaps we should also add a check for `np.matrix` objects.

In terms of operations, one big class that comes to mind are aggregations, e.g., `.mean()`. It would be good to make sure that these work.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-493803589,https://api.github.com/repos/pydata/xarray/issues/2956,493803589,MDEyOklzc3VlQ29tbWVudDQ5MzgwMzU4OQ==,14808389,2019-05-20T00:01:26Z,2019-05-20T00:01:26Z,MEMBER,"Most of the items above are implemented in [unit-support](/keewis/xarray/tree/unit-support), even support for array wrappers with units like `pint` (if my tests are sufficient for deciding that: `pint` still complains/warns about stripped units). The calls to `asarray` and `asanyarray` are skipped based on whether any of the `__array_*__` methods and the attributes `unit` or `units` exist.

I did not push these commits to this PR because most of it does not have anything to do with subclasses. I did not open a new PR for the branch either because it builds on this one and because I'd like to receive feedback on any of this first.

Combining this with `dask` arrays should still fail, though.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666
https://github.com/pydata/xarray/pull/2956#issuecomment-491641438,https://api.github.com/repos/pydata/xarray/issues/2956,491641438,MDEyOklzc3VlQ29tbWVudDQ5MTY0MTQzOA==,5635139,2019-05-13T00:19:19Z,2019-05-13T00:19:19Z,MEMBER,"Looks great! Thanks @keewis 

I don't know this area that well, so I'll defer to someone else on a proper review","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,443157666