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/issues/6142#issuecomment-1138997020,https://api.github.com/repos/pydata/xarray/issues/6142,1138997020,IC_kwDOAMm_X85D47cc,5635139,2022-05-26T20:27:19Z,2022-05-26T20:27:19Z,MEMBER,"Ah, that's a good case @headtr1ck . So `str | Iterable[Hashable]` works when one is checked before the other, but not when they're required to be disjoint, like an `overload`.

I don't have an immediate solution in mind unfortunately. I'm not sure having different return types is a great design in general, though I can see the logic for it in this case...","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1094725752
https://github.com/pydata/xarray/issues/6142#issuecomment-1132117191,https://api.github.com/repos/pydata/xarray/issues/6142,1132117191,IC_kwDOAMm_X85DerzH,5635139,2022-05-19T19:28:04Z,2022-05-19T19:28:04Z,MEMBER,"> Only remotely related to this issue, but would it help to type the dimension (or variable names etc) Mappings with covariant Hashable keys to prevent the issue that `{""a"":1}` is incompatible with `Mapping[Hashable, Any]`?

I spent a non-trivial amount of time on this a year ago or so — my understanding is that `Mapping` was _not_ covariant in its keys, exactly as you point out.

But I'm also not sure we lose anything with `Mapping[Any, foo]` — the key needs to be `Hashable` anyway. I don't have a strong objection, but do we gain anything?

e.g. https://mypy-play.net/?mypy=latest&python=3.10&gist=a3ea9f6fce5a678803bd7563a54cd9ca

> See https://mypy-play.net/?mypy=latest&python=3.10&gist=b2c27a5ca4aad9e8ce63cd74dc4032b0

Very cool! I didn't even know about this.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1094725752
https://github.com/pydata/xarray/issues/6142#issuecomment-1116791799,https://api.github.com/repos/pydata/xarray/issues/6142,1116791799,IC_kwDOAMm_X85CkOP3,5635139,2022-05-04T00:21:34Z,2022-05-04T00:21:34Z,MEMBER,"> there are so many inconsistencies that I even wonder if it is possible to use anything but strings in ""production"".

I would have thought this is indeed the case. I think we're quite open to adjusting this so that it works, but it would probably needs some work, including defining common patterns — e.g. the title of this issue is a good approach

> Apart from arguments randomly being called `dim` or `dims`

I also think we'd be up for reforming this! Generally this is the first arg and so only used positionally, but it still makes sense to have them consistent.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1094725752
https://github.com/pydata/xarray/issues/6142#issuecomment-1006622944,https://api.github.com/repos/pydata/xarray/issues/6142,1006622944,IC_kwDOAMm_X847_9jg,5635139,2022-01-06T14:13:58Z,2022-01-06T14:13:58Z,MEMBER,"Thanks for writing this out. I realize something clever about the proposal:

Our very first line of code in the docs passes dims as a tuple `dims=(""x"", ""y"")`: https://xarray.pydata.org/en/stable/getting-started-guide/quick-overview.html#create-a-dataarray

This will still work as two dims, since having `str | Iterable[Hashable]` rather than `Hashable | Iterable[Hashable]` means it will fail the first check. So if someone really wants a single dim as `(""x"", ""y"")`, they can pass `((""x"", ""y""),)`.

Does this mean that this would be confusion free?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1094725752