add proper errors for missing kwargs

src/gt4py/next/embedded/operators.py

@@ -16,7 +16,7 @@
 
 from gt4py import eve
 from gt4py._core import definitions as core_defs
-from gt4py.next import common, constructors, field_utils, utils
+from gt4py.next import common, constructors, errors, field_utils, utils
 from gt4py.next.embedded import common as embedded_common, context as embedded_context
 
 
@@ -56,7 +56,11 @@ def field_operator_call(
 
     else:
         # field_operator called directly
+        if "offset_provider" not in kwargs:
+            raise errors.MissingArgumentError(None, "offset_provider", True)
         offset_provider = kwargs.pop("offset_provider", None)
+        if "out" not in kwargs:
+            raise errors.MissingArgumentError(None, "out", True)
         out = kwargs.pop("out")
         domain = kwargs.pop("domain", None)
 

src/gt4py/next/errors/__init__.py

@@ -21,6 +21,7 @@
 from .exceptions import (
     DSLError,
     InvalidParameterAnnotationError,
+    MissingArgumentError,
     MissingAttributeError,
     MissingParameterAnnotationError,
     UndefinedSymbolError,
@@ -33,6 +34,7 @@
     "InvalidParameterAnnotationError",
     "MissingAttributeError",
     "MissingParameterAnnotationError",
+    "MissingArgumentError",
     "UndefinedSymbolError",
     "UnsupportedPythonFeatureError",
     "set_verbose_exceptions",

src/gt4py/next/errors/exceptions.py

@@ -81,6 +81,18 @@ def __init__(self, location: Optional[SourceLocation], attr_name: str) -> None:
         self.attr_name = attr_name
 
 
+class MissingArgumentError(DSLError):
+    arg_name: str
+    is_kwarg: bool
+
+    def __init__(self, location: Optional[SourceLocation], arg_name: str, is_kwarg: bool) -> None:
+        super().__init__(
+            location, f"expected {'keyword-' if is_kwarg else ''}argument '{arg_name}'"
+        )
+        self.attr_name = arg_name
+        self.is_kwarg = is_kwarg
+
+
 class TypeError_(DSLError):
     def __init__(self, location: Optional[SourceLocation], message: str) -> None:
         super().__init__(location, message)

src/gt4py/next/ffront/decorator.py

@@ -33,7 +33,7 @@
 from gt4py._core import definitions as core_defs
 from gt4py.eve import utils as eve_utils
 from gt4py.eve.extended_typing import Any, Optional
-from gt4py.next import allocators as next_allocators, embedded as next_embedded
+from gt4py.next import allocators as next_allocators, embedded as next_embedded, errors
 from gt4py.next.common import Dimension, DimensionKind, GridType
 from gt4py.next.embedded import operators as embedded_operators
 from gt4py.next.ffront import (
@@ -682,6 +682,7 @@ def as_program(
         self._program_cache[hash_] = Program(
             past_node=past_node,
             closure_vars=closure_vars,
+            definition=None,
             backend=self.backend,
             grid_type=self.grid_type,
         )
@@ -694,7 +695,12 @@ def __call__(
     ) -> None:
         if not next_embedded.context.within_context() and self.backend is not None:
             # non embedded execution
-            offset_provider = kwargs.pop("offset_provider", None)
+            if "offset_provider" not in kwargs:
+                raise errors.MissingArgumentError(None, "offset_provider", True)
+            offset_provider = kwargs.pop("offset_provider")
+
+            if "out" not in kwargs:
+                raise errors.MissingArgumentError(None, "out", True)
             out = kwargs.pop("out")
             args, kwargs = type_info.canonicalize_arguments(self.foast_node.type, args, kwargs)
             # TODO(tehrengruber): check all offset providers are given

tests/next_tests/integration_tests/multi_feature_tests/ffront_tests/test_embedded_regression.py

@@ -15,6 +15,7 @@
 import pytest
 
 from gt4py import next as gtx
+from gt4py.next import errors
 
 from next_tests.integration_tests import cases
 from next_tests.integration_tests.cases import IField, cartesian_case  # noqa: F401 # fixtures
@@ -38,3 +39,19 @@ def copy(a: IField) -> IField:
         # due to `fieldview_backend` fixture (dependency of `cartesian_case`)
         # setting the default backend to something invalid.
         _ = copy(a, out=a, offset_provider={})
+
+
+def test_missing_arg(cartesian_case):  # noqa: F811 # fixtures
+    """Test that calling a field_operator without required args raises an error."""
+
+    @gtx.field_operator(backend=cartesian_case.backend)
+    def copy(a: IField) -> IField:
+        return a
+
+    a = cases.allocate(cartesian_case, copy, "a")()
+
+    with pytest.raises(errors.MissingArgumentError, match="'out'"):
+        _ = copy(a, offset_provider={})
+
+    with pytest.raises(errors.MissingArgumentError, match="'offset_provider'"):
+        _ = copy(a, out=a)