tests: Add deprecation warning for old subdomain API and update tests

Author: EdCaunt

devito/deprecations.py

@@ -7,14 +7,23 @@ class DevitoDeprecation():
     @cached_property
     def coeff_warn(self):
         warn("The Coefficient API is deprecated and will be removed, coefficients should"
-             "be passed directly to the derivative object `u.dx(weights=...)",
+             " be passed directly to the derivative object `u.dx(weights=...)",
              DeprecationWarning, stacklevel=2)
         return
 
     @cached_property
     def symbolic_warn(self):
         warn("coefficients='symbolic' is deprecated, coefficients should"
-             "be passed directly to the derivative object `u.dx(weights=...)",
+             " be passed directly to the derivative object `u.dx(weights=...)",
+             DeprecationWarning, stacklevel=2)
+        return
+
+    @cached_property
+    def subdomain_warn(self):
+        warn("Passing `SubDomain`s to `Grid` on instantiation using `mygrid ="
+             " Grid(..., subdomains=(mydomain, ...))` is deprecated. The `Grid`"
+             " should instead be passed as a kwarg when instantiating a subdomain"
+             " `mydomain = MyDomain(grid=mygrid)`",
              DeprecationWarning, stacklevel=2)
         return
 

devito/types/grid.py

@@ -17,6 +17,7 @@
 from devito.types.dimension import (Dimension, SpaceDimension, TimeDimension,
                                     Spacing, SteppingDimension, SubDimension,
                                     MultiSubDimension, DefaultDimension)
+from devito.deprecations import deprecations
 
 __all__ = ['Grid', 'SubDomain', 'SubDomainSet']
 
@@ -211,6 +212,8 @@ def __init__(self, shape, extent=None, origin=None, dimensions=None,
             raise ValueError("`time_dimension` must be None or of type TimeDimension")
 
         # Initialize SubDomains for legacy interface
+        if subdomains is not None:
+            deprecations.subdomain_warn
         self._subdomains = tuple(i for i in (Domain(), Interior(), *as_tuple(subdomains)))
         for i in self._subdomains:
             i.__subdomain_finalize_legacy__(self)

examples/userapi/07_functions_on_subdomains.ipynb

@@ -3015,7 +3015,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "assert np.isclose(np.linalg.norm(rec.data), 4263.564, atol=0, rtol=1e-4)"
+    "assert np.isclose(np.linalg.norm(rec.data), 4263.511, atol=0, rtol=1e-4)"
    ]
   }
  ],