id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
2244518111,PR_kwDOAMm_X85suNEO,8946,Fix upcasting with python builtin numbers and numpy 2,1828519,open,0,,,18,2024-04-15T20:07:42Z,2024-04-29T12:38:55Z,,CONTRIBUTOR,,0,pydata/xarray/pulls/8946,"See #8402 for more discussion. Bottom line is that numpy 2 changes the rules for casting between two inputs. Due to this and xarray's preference for promoting python scalars to 0d arrays (scalar arrays), xarray objects are being upcast to higher data types when they previously didn't.

I'm mainly opening this PR for further and more detailed discussion.

CC @dcherian

- [ ] Closes #8402
- [ ] Tests added
- [ ] User visible changes (including notable bug fixes) are documented in `whats-new.rst`
- [ ] New functions/methods are listed in `api.rst`
","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/8946/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull
1750685808,PR_kwDOAMm_X85SqoXL,7905,Add '.hdf' extension to 'netcdf4' backend,1828519,open,0,,,10,2023-06-10T00:45:15Z,2023-06-14T15:25:08Z,,CONTRIBUTOR,,0,pydata/xarray/pulls/7905,"I'm helping @joleenf debug an issue where some old code that uses `xr.open_dataset` no longer works since the introduction of engines or at least as far as we can tell. The main issue is that she's using code that assumes the NetCDF4 C library was compiled with HDF4 support (ex. conda-forge builds with this functionality enabled). So in this case `netCDF4.Dataset(""my_file.hdf"")` can actually read the HDF4 file through the NetCDF4 C library.

However, with `xr.open_dataset(""my_file.hdf"")` will fail because xarray (or rather the netcdf4 engine) doesn't know that it could potentially read HDF4 files. This PR adds the `.hdf` extension to the 'netcdf4' engine to allow this to be automatic without needing `engine='netcdf4'` to be specified.

What do people think? I didn't want to put any more work into this until others weighed in.

- [ ] Closes #xxxx
- [ ] Tests added
- [ ] User visible changes (including notable bug fixes) are documented in `whats-new.rst`
- [ ] New functions/methods are listed in `api.rst`
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