Zip as possible Zarr extenstion (#426)

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### Pull Request Checklist:
- [ ] This PR addresses an already opened issue (for bug fixes /
features)
    - This PR fixes #xyz
- [x] (If applicable) Documentation has been added / updated (for bug
fixes / features).
- [ ] (If applicable) Tests have been added.
- [x] This PR does not seem to break the templates.
- [x] CHANGELOG.rst has been updated (with summary of main changes).
- [x] Link to issue (:issue:`number`) and pull request (:pull:`number`)
has been added.

### What kind of change does this PR introduce?

* The directory parser will now assign a "zarr" format to files with
.zarr.zip or .zip extensions. The extension still needs to be included
in the pattern.
* `get_engine` returns `zarr` for the same two file extensions.

### Does this PR introduce a breaking change?
No.

### Other information:

CHANGELOG.rst

@@ -16,6 +16,7 @@ Internal changes
 ^^^^^^^^^^^^^^^^
 * Include domain in `weight_location` in ``regrid_dataset``. (:pull:`414`).
 * Added pins to `xarray`, `xclim`, `h5py`, and `netcdf4`. (:pull:`414`).
+* Add ``.zip`` and ``.zarr.zip`` as possible file extensions for Zarr datasets. (:pull:`426`).
 
 v0.9.1 (2024-06-04)
 -------------------

src/xscen/catutils.py

@@ -39,6 +39,18 @@
 # ## File finding and path parsing ## #
 
 
+SUFFIX_TO_FORMAT = {
+    ".nc": "nc",
+    ".nc4": "nc",
+    ".zip": "zarr",
+    ".zarr.zip": "zarr",
+    ".zarr": "zarr",
+}
+"""Mapping from file suffix to format.
+
+This is used to populate the "format" esm catalog column from the parsed path.
+"""
+
 EXTRA_PARSE_TYPES = {}
 """Extra parse types to add to parse's default.
 
@@ -223,7 +235,7 @@ def _name_parser(
         return None
 
     d["path"] = abs_path
-    d["format"] = path.suffix[1:]
+    d["format"] = SUFFIX_TO_FORMAT.get(path.suffix, path.suffix[1:])
 
     if "DATES" in d:
         d["date_start"], d["date_end"] = d.pop("DATES")

src/xscen/io.py

@@ -47,7 +47,10 @@
 
 
 def get_engine(file: Union[str, os.PathLike]) -> str:
-    """Use functionality of h5py to determine if a NetCDF file is compatible with h5netcdf.
+    """Determine which Xarray engine should be used to open the given file.
+
+    The .zarr, .zarr.zip and .zip extensions are recognized as Zarr datasets,
+    the rest is seen as a netCDF. If the file is HDF5, the h5netcdf engine is used.
 
     Parameters
     ----------
@@ -60,7 +63,7 @@ def get_engine(file: Union[str, os.PathLike]) -> str:
         Engine to use with xarray
     """
     # find the ideal engine for xr.open_mfdataset
-    if Path(file).suffix == ".zarr":
+    if Path(file).suffix in [".zarr", ".zip", ".zarr.zip"]:
         engine = "zarr"
     elif h5py.is_hdf5(file):
         engine = "h5netcdf"