dsl: Add tests for OOB accesses

tests/test_derivatives.py

@@ -488,3 +488,64 @@ def test_shifted_grad(self, shift, ndim):
             x0 = (None if shift is None else d + shift[i] * d.spacing if
                   type(shift) is tuple else d + shift * d.spacing)
             assert gi == getattr(f, 'd%s' % d.name)(x0=x0).evaluate
+
+    @pytest.mark.parametrize('exprs, error,', [
+        ### Dimensions
+        # OOB access avoided by iteration space shrinking
+        (['Eq(so2.forward, so2.dx.dx.dx)'],None),
+        (['Eq(so2.forward, (so2+so0).dx2 )'],None),
+        (['Eq(so2.forward, so2.biharmonic(1/so0) )'],None),
+        
+        ### SubDimensions (Thickness == 0)
+        # No OOB indices, no error (Dimension or SubDimension)
+        (['Eq(so1[t+1,x,y], so1[t,x-1,y] + so1[t,x+1,y] )'],None), 
+        (['Eq(so1[t+1,xi0,y], so1[t,xi0-1,y] + so1[t,xi0+1,y] )'],None), 
+        # These examples would get SEGFAULT because SubDimenions are not being handled
+        # We are raising exceptions, but we could also increase thickness
+        (['Eq(sd0so2.forward, sd0so2.dx.dx.dx)'],ValueError), # This should get segfault althoug it doesn't
+        (['Eq(sd0so2.forward, (sd0so2+sd0so0).dx2 )'],ValueError),
+        (['Eq(so0[t+1,xi0,y], so0[t,xi0-1,y] + so0[t,xi0+1,y] )'],ValueError),
+
+        ### SubDimensions (Thickness == 1) (Not covered by current patch)
+        # These examples pass just because of thickness size support their OOB indices
+        (['Eq(sd1so2.forward, sd1so2.dx.dx.dx)'],None),
+        (['Eq(sd1so2.forward, (sd1so2+sd1so0).dx2 )'],None),
+        (['Eq(so1[t+1,xi1,y], so1[t,xi1-2,y] + so1[t,xi1+2,y] )'],None),
+        # This would still segfault
+        # (['Eq(so1[t+1,xi1,y], so1[t,xi1-3,y] + so1[t,xi1+3,y] )'],ValueError),
+        ])
+    def test_oobs(self, exprs, error):
+
+        grid = Grid(tuple([100]*2))
+        x , y = grid.dimensions
+        t = grid.stepping_dim
+
+        xi0 = SubDimension.middle(name='xi0', parent=x, thickness_left=0, thickness_right=0)
+        xi1 = SubDimension.middle(name='xi1', parent=x, thickness_left=1, thickness_right=1)
+
+        so0 = TimeFunction(name="so0", grid=grid, time_order=1, space_order=0)
+        so1 = TimeFunction(name="so1", grid=grid, time_order=1, space_order=1)
+        so2 = TimeFunction(name="so2", grid=grid, time_order=1, space_order=2)
+
+        sd0so0 = TimeFunction(name="sdso0", grid=grid, time_order=1, space_order=0, dimensions=(t,xi0,y))
+        sd0so1 = TimeFunction(name="sdso1", grid=grid, time_order=1, space_order=1, dimensions=(t,xi0,y))
+        sd0so2 = TimeFunction(name="sdso2", grid=grid, time_order=1, space_order=2, dimensions=(t,xi0,y))
+
+        sd1so0 = TimeFunction(name="sdso0", grid=grid, time_order=1, space_order=0, dimensions=(t,xi1,y))
+        sd1so1 = TimeFunction(name="sdso1", grid=grid, time_order=1, space_order=1, dimensions=(t,xi1,y))
+        sd1so2 = TimeFunction(name="sdso2", grid=grid, time_order=1, space_order=2, dimensions=(t,xi1,y))
+
+        # List comprehension would need explicit locals/globals mappings to eval
+        for i, e in enumerate(list(exprs)):
+            exprs[i] = eval(e)
+        try:
+            op = Operator(exprs)
+        except Exception as e:
+            if error is None or not isinstance(e, error):
+                assert False, "Not expected: %s %s" % (type(e),e)
+        else:
+            if error is not None:
+                assert False, "Should raise an %s exception" % error
+            print('arguments: ', op.arguments(time_M=0))
+            print('operator:\n',op)
+            op.apply(time_M=5)