Improve predictability of DataQuery, DataID, and dependency tree

doc/source/dev_guide/satpy_internals.rst

@@ -137,8 +137,9 @@ DataID and DataQuery interactions
 Different DataIDs and DataQuerys can have different metadata items defined. As such
 we define equality between different instances of these classes, and across the classes
 as equality between the sorted key/value pairs shared between the instances.
-If a DataQuery has one or more values set to `'*'`, the corresponding key/value pair will be omitted from the comparison.
-Instances sharing no keys will no be equal.
+If a DataQuery has one or more values set to ``'*'``, the corresponding key/value pair will be omitted from the comparison.
+If any key in a DataQuery (not equal to ``"*"``) is missing from a DataID they
+are considered not equal.
 
 
 Breaking changes from DatasetIDs
@@ -151,8 +152,9 @@ Breaking changes from DatasetIDs
 Creating DataID for tests
 =========================
 
-Sometimes, it is useful to create `DataID` instances for testing purposes. For these cases, the `satpy.tests.utils` module
-now has a `make_dsid` function that can be used just for this::
+Sometimes, it is useful to create ``DataID`` instances for testing purposes.
+For these cases, the ``satpy.tests.utils`` module now has a ``make_dataid``
+function that can be used just for this::
 
   from satpy.tests.utils import make_dataid
   did = make_dataid(name='camembert', modifiers=('runny',))

satpy/composites/__init__.py

@@ -29,7 +29,7 @@
 import satpy
 from satpy.aux_download import DataDownloadMixin
 from satpy.dataset import DataID, combine_metadata
-from satpy.dataset.dataid import minimal_default_keys_config
+from satpy.dataset.id_keys import minimal_default_keys_config
 from satpy.utils import unify_chunks
 from satpy.writers import get_enhanced_image
 

satpy/composites/config_loader.py

@@ -30,7 +30,7 @@
 import satpy
 from satpy import DataID, DataQuery
 from satpy._config import config_search_paths, get_entry_points_config_dirs, glob_config
-from satpy.dataset.dataid import minimal_default_keys_config
+from satpy.dataset.id_keys import minimal_default_keys_config
 from satpy.utils import recursive_dict_update
 
 logger = logging.getLogger(__name__)

satpy/dataset/__init__.py

@@ -19,5 +19,6 @@
 
 from .anc_vars import dataset_walker, replace_anc  # noqa
 from .data_dict import DatasetDict, get_key  # noqa
-from .dataid import DataID, DataQuery, ModifierTuple, WavelengthRange, create_filtered_query  # noqa
+from .dataid import DataID, DataQuery, create_filtered_query  # noqa
+from .id_keys import ModifierTuple, WavelengthRange  # noqa
 from .metadata import combine_metadata  # noqa

satpy/dataset/anc_vars.py

@@ -17,7 +17,8 @@
 # satpy.  If not, see <http://www.gnu.org/licenses/>.
 """Utilities for dealing with ancillary variables."""
 
-from .dataid import DataID, default_id_keys_config
+from .dataid import DataID
+from .id_keys import default_id_keys_config
 
 
 def dataset_walker(datasets):

satpy/dataset/data_dict.py

@@ -19,7 +19,8 @@
 
 import numpy as np
 
-from .dataid import DataID, create_filtered_query, minimal_default_keys_config
+from .dataid import DataID, create_filtered_query
+from .id_keys import minimal_default_keys_config
 
 
 class TooManyResults(KeyError):
@@ -143,16 +144,18 @@ def get_key(self, match_key, num_results=1, best=True, **dfilter):  # noqa: D417
         """Get multiple fully-specified keys that match the provided query.
 
         Args:
-            key (DataID): DataID of query parameters to use for
-                          searching. Any parameter that is `None`
-                          is considered a wild card and any match is
-                          accepted. Can also be a string representing the
-                          dataset name or a number representing the dataset
-                          wavelength.
+            match_key (DataID): DataID of query parameters to use for
+                searching. Any parameter that is `None`
+                is considered a wild card and any match is
+                accepted. Can also be a string representing the
+                dataset name or a number representing the dataset
+                wavelength.
             num_results (int): Number of results to return. If `0` return all,
-                               if `1` return only that element, otherwise
-                               return a list of matching keys.
-            **dfilter (dict): See `get_key` function for more information.
+                if `1` return only that element, otherwise
+                return a list of matching keys.
+            best (bool): Sort results to get "best" result first
+                (default: True). See `get_best_dataset_key` for details.
+            **dfilter (dict): See :func:`get_key` function for more information.
 
         """
         return get_key(match_key, self.keys(), num_results=num_results,