Control setting and display of cached data elements

Changelog.rst

@@ -1,10 +1,22 @@
 Version NEXTVERSION
 -------------------
 
-**2025-12-??**
-
+**2026-01-??**
+
+* New function to control the creation of cached elements during data
+  display: `cf.display_data`
+  (https://github.com/NCAS-CMS/cf-python/issues/913)
+* New methods: `cf.Data.get_cached_elements`
+  `cf.Data.cache_elements`
+  (https://github.com/NCAS-CMS/cf-python/issues/913)
+* Set cached elements during `cf.Data.__init__`
+  (https://github.com/NCAS-CMS/cf-python/issues/913)
+* Removed the `cf.constants.CONSTANTS` dictionary, replacing it
+  `cf.ConstantAccess.constants`
+  (https://github.com/NCAS-CMS/cf-python/issues/902)
 * Reduce the time taken to import `cf`
   (https://github.com/NCAS-CMS/cf-python/issues/902)
+* Changed dependency: ``cfdm>=1.12.4.0, <1.12.5.0``
 
 ----
 

cf/functions.py

@@ -156,6 +156,7 @@ def configuration(
     tempdir=None,
     chunksize=None,
     log_level=None,
+    display_data=None,
     regrid_logging=None,
     relaxed_identities=None,
     bounds_combination_mode=None,
@@ -177,6 +178,7 @@ def configuration(
     * `tempdir`
     * `chunksize`
     * `log_level`
+    * `display_data`
     * `regrid_logging`
     * `relaxed_identities`
     * `bounds_combination_mode`
@@ -200,10 +202,10 @@ def configuration(
     .. versionadded:: 3.6.0
 
     .. seealso:: `atol`, `rtol`, `tempdir`, `chunksize`,
-                 `total_memory`, `log_level`, `regrid_logging`,
-                 `relaxed_identities`, `bounds_combination_mode`,
-                 `active_storage`, `active_storage_url`,
-                 `active_storage_max_requests`
+                 `total_memory`, `log_level`, `display_data`,
+                 `regrid_logging`, `relaxed_identities`,
+                 `bounds_combination_mode`, `active_storage`,
+                 `active_storage_url`, `active_storage_max_requests`
 
     :Parameters:
 
@@ -245,6 +247,12 @@ def configuration(
             * ``'DETAIL'`` (``3``);
             * ``'DEBUG'`` (``-1``).
 
+        display_data `bool` or `Constant`, optional
+            The new display data option. The default is to not change
+            the current behaviour.
+
+            .. versionadded:: NEXTVERSION
+
         regrid_logging: `bool` or `Constant`, optional
             The new value (either True to enable logging or False to
             disable it). The default is to not change the current
@@ -303,6 +311,7 @@ def configuration(
      'log_level': 'WARNING',
      'bounds_combination_mode': 'AND',
      'chunksize': 82873466.88000001,
+     'display_data': True,
      'active_storage': False,
      'active_storage_url': None,
      'active_storage_max_requests': 100}
@@ -320,6 +329,7 @@ def configuration(
      'log_level': 'WARNING',
      'bounds_combination_mode': 'AND',
      'chunksize': 75000000.0,
+     'display_data': True,
      'active_storage': False,
      'active_storage_url': None,
      'active_storage_max_requests': 100}
@@ -347,6 +357,7 @@ def configuration(
      'log_level': 'INFO',
      'bounds_combination_mode': 'AND',
      'chunksize': 75000000.0,
+     'display_data': True,
      'active_storage': False,
      'active_storage_url': None}
     >>> with cf.configuration(atol=9, rtol=10):
@@ -360,6 +371,7 @@ def configuration(
      'log_level': 'INFO',
      'bounds_combination_mode': 'AND',
      'chunksize': 75000000.0,
+     'display_data': True,
      'active_storage': False,
      'active_storage_url': None,
      'active_storage_max_requests': 100}
@@ -372,6 +384,7 @@ def configuration(
      'log_level': 'INFO',
      'bounds_combination_mode': 'AND',
      'chunksize': 75000000.0,
+     'display_data': True,
      'active_storage': False,
      'active_storage_url': None,
      'active_storage_max_requests': 100}
@@ -402,6 +415,7 @@ def configuration(
         new_tempdir=tempdir,
         new_chunksize=chunksize,
         new_log_level=log_level,
+        new_display_data=display_data,
         new_regrid_logging=regrid_logging,
         new_relaxed_identities=relaxed_identities,
         bounds_combination_mode=bounds_combination_mode,
@@ -445,6 +459,7 @@ def _configuration(_Configuration, **kwargs):
         "new_tempdir": tempdir,
         "new_chunksize": chunksize,
         "new_log_level": log_level,
+        "new_display_data": display_data,
         "new_regrid_logging": regrid_logging,
         "new_relaxed_identities": relaxed_identities,
         "bounds_combination_mode": bounds_combination_mode,
@@ -459,10 +474,6 @@ def _configuration(_Configuration, **kwargs):
 
     old = ConstantAccess.constants(copy=True)
 
-    #    old = {name.lower(): val for name, val in CONSTANTS.items()}
-    #
-    #    old.pop("total_memory", None)
-
     # Filter out 'None' kwargs from configuration() defaults. Note that this
     # does not filter out '0' or 'True' values, which is important as the user
     # might be trying to set those, as opposed to None emerging as default.
@@ -552,7 +563,6 @@ def FREE_MEMORY():
 # Functions inherited from cfdm
 # --------------------------------------------------------------------
 class ConstantAccess(cfdm.ConstantAccess):
-    _constants = {}
     _Constant = Constant
 
     def __docstring_substitutions__(self):
@@ -576,6 +586,10 @@ class log_level(ConstantAccess, cfdm.log_level):
     _reset_log_emergence_level = _reset_log_emergence_level
 
 
+class display_data(ConstantAccess, cfdm.display_data):
+    pass
+
+
 class regrid_logging(ConstantAccess):
     """Whether or not to enable `esmpy` regridding logging.
 

cf/mixin/properties.py

@@ -7,8 +7,6 @@
     _DEPRECATION_ERROR_KWARGS,
     _DEPRECATION_ERROR_METHOD,
 )
-from ..functions import atol as cf_atol
-from ..functions import rtol as cf_rtol
 from ..mixin_container import Container
 from ..query import Query
 from ..units import Units
@@ -34,32 +32,6 @@ def __new__(cls, *args, **kwargs):
         instance._Data = Data
         return instance
 
-    # ----------------------------------------------------------------
-    # Private attributes
-    # ----------------------------------------------------------------
-    @property
-    def _atol(self):
-        """Return the tolerance on absolute differences between real
-        numbers, as returned by the `cf.atol` function.
-
-        This is used by, for example, the `_equals` method.
-
-        """
-        return cf_atol().value
-
-    @property
-    def _rtol(self):
-        """Return the tolerance on relative differences between real
-        numbers, as returned by the `cf.rtol` function.
-
-        This is used by, for example, the `_equals` method.
-
-        """
-        return cf_rtol().value
-
-    # ----------------------------------------------------------------
-    # Private methods
-    # ----------------------------------------------------------------
     def _matching_values(self, value0, value1, units=False, basic=False):
         """Whether two values match.
 
@@ -100,9 +72,6 @@ def _matching_values(self, value0, value1, units=False, basic=False):
 
             return self._equals(value1, value0, basic=basic)
 
-    # ----------------------------------------------------------------
-    # Attributes
-    # ----------------------------------------------------------------
     @property
     def id(self):
         """An identity for the {{class}} object.
@@ -150,9 +119,6 @@ def id(self):
                 f"{self.__class__.__name__} doesn't have attribute 'id'"
             )
 
-    # ----------------------------------------------------------------
-    # CF properties
-    # ----------------------------------------------------------------
     @property
     def calendar(self):
         """The calendar CF property.
@@ -554,9 +520,6 @@ def valid_range(self, value):
     def valid_range(self):
         self.del_property("valid_range", default=AttributeError())
 
-    # ----------------------------------------------------------------
-    # Methods
-    # ----------------------------------------------------------------
     def get_property(self, prop, default=ValueError()):
         """Get a CF property.
 

cf/mixin2/container.py

@@ -6,7 +6,6 @@
 """
 
 from ..docstring import _docstring_substitution_definitions
-from ..functions import atol, rtol
 
 
 class Container:
@@ -55,23 +54,3 @@ def __docstring_package_depth__(self):
 
         """
         return 0
-
-    @property
-    def _atol(self):
-        """Internal alias for `{{package}}.atol`.
-
-        An alias is necessary to avoid a name clash with the keyword
-        argument of identical name (`atol`) in calling functions.
-
-        """
-        return atol().value
-
-    @property
-    def _rtol(self):
-        """Internal alias for `{{package}}.rtol`.
-
-        An alias is necessary to avoid a name clash with the keyword
-        argument of identical name (`rtol`) in calling functions.
-
-        """
-        return rtol().value