Release v073

## v0.7.3 (2026-04-16)

### Fix

- make time format more strict to stop invalid time date flowing (#92)
- enhance duckdb casting to be less permissive of poorly formatted dates and trim whitespace

### Refactor

- integrated duckdb casting into data contract and added initial spark casting

Author: georgeRobertson

CHANGELOG.md

@@ -1,3 +1,14 @@
+## v0.7.3 (2026-04-16)
+
+### Fix
+
+- make time format more strict to stop invalid time date flowing (#92)
+- enhance duckdb casting to be less permissive of poorly formatted dates and trim whitespace
+
+### Refactor
+
+- integrated duckdb casting into data contract and added initial spark casting
+
 ## v0.7.2 (2026-04-02)
 
 ### Fix

poetry.lock

@@ -24,7 +24,7 @@ Issues = "https://github.com/NHSDigital/data-validation-engine/issues"
 Changelog = "https://github.com/NHSDigital/data-validation-engine/blob/main/CHANGELOG.md"
 
 [tool.poetry]
-version = "0.7.2"
+version = "0.7.3"
 packages = [
     { include = "dve", from = "src" },
 ]

pyproject.toml

@@ -31,6 +31,7 @@
     duckdb_read_parquet,
     duckdb_record_index,
     duckdb_write_parquet,
+    get_duckdb_cast_statement_from_annotation,
     get_duckdb_type_from_annotation,
     relation_is_empty,
 )
@@ -101,18 +102,7 @@ def create_entity_from_py_iterator(  # pylint: disable=unused-argument
         _lazy_df = pl.LazyFrame(records, polars_schema)  # type: ignore # pylint: disable=unused-variable
         return self._connection.sql("select * from _lazy_df")
 
-    @staticmethod
-    def generate_ddb_cast_statement(
-        column_name: str, dtype: DuckDBPyType, null_flag: bool = False
-    ) -> str:
-        """Helper method to generate sql statements for casting datatypes (permissively).
-        Current duckdb python API doesn't play well with this currently.
-        """
-        if not null_flag:
-            return f'try_cast("{column_name}" AS {dtype}) AS "{column_name}"'
-        return f'cast(NULL AS {dtype}) AS "{column_name}"'
-
-    # pylint: disable=R0914
+    # pylint: disable=R0914,R0915
     def apply_data_contract(
         self,
         working_dir: URI,
@@ -180,12 +170,16 @@ def apply_data_contract(
 
                 casting_statements = [
                     (
-                        self.generate_ddb_cast_statement(column, dtype)
+                        get_duckdb_cast_statement_from_annotation(column, mdl_fld.annotation)
+                        + f""" AS "{column}" """
                         if column in relation.columns
-                        else self.generate_ddb_cast_statement(column, dtype, null_flag=True)
+                        else f"CAST(NULL AS {ddb_schema[column]}) AS {column}"
                     )
-                    for column, dtype in ddb_schema.items()
+                    for column, mdl_fld in entity_fields.items()
                 ]
+                casting_statements.append(
+                    f"CAST({RECORD_INDEX_COLUMN_NAME} AS {get_duckdb_type_from_annotation(int)}) AS {RECORD_INDEX_COLUMN_NAME}"  # pylint: disable=C0301
+                )
                 try:
                     relation = relation.project(", ".join(casting_statements))
                 except Exception as err:  # pylint: disable=broad-except

src/dve/core_engine/backends/implementations/duckdb/contract.py

@@ -313,3 +313,108 @@ def duckdb_record_index(cls):
     setattr(cls, "add_record_index", _add_duckdb_record_index)
     setattr(cls, "drop_record_index", _drop_duckdb_record_index)
     return cls
+
+
+def _cast_as_ddb_type(field_expr: str, type_annotation: Any) -> str:
+    """Cast to Duck DB type"""
+    return f"""try_cast({field_expr} as {get_duckdb_type_from_annotation(type_annotation)})"""
+
+
+def _ddb_safely_quote_name(field_name: str) -> str:
+    """Quote field names in case reserved"""
+    try:
+        sep_idx = field_name.index(".")
+        return f'"{field_name[: sep_idx]}"' + field_name[sep_idx:]
+    except ValueError:
+        return f'"{field_name}"'
+
+
+# pylint: disable=R0801,R0911,R0912
+def get_duckdb_cast_statement_from_annotation(
+    element_name: str,
+    type_annotation: Any,
+    parent_element: bool = True,
+    date_regex: str = r"^[0-9]{4}-[0-9]{2}-[0-9]{2}$",
+    timestamp_regex: str = r"^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}((\+|\-)[0-9]{2}:[0-9]{2})?$",  # pylint: disable=C0301
+    time_regex: str = r"^[0-9]{2}:[0-9]{2}:[0-9]{2}$",
+) -> str:
+    """Generate casting statements for duckdb relations from type annotations"""
+    type_origin = get_origin(type_annotation)
+
+    quoted_name = _ddb_safely_quote_name(element_name)
+
+    # An `Optional` or `Union` type, check to ensure non-heterogenity.
+    if type_origin is Union:
+        python_type = _get_non_heterogenous_type(get_args(type_annotation))
+        return get_duckdb_cast_statement_from_annotation(
+            element_name, python_type, parent_element, date_regex, timestamp_regex
+        )
+
+    # Type hint is e.g. `List[str]`, check to ensure non-heterogenity.
+    if type_origin is list or (isinstance(type_origin, type) and issubclass(type_origin, list)):
+        element_type = _get_non_heterogenous_type(get_args(type_annotation))
+        stmt = f"list_transform({quoted_name}, x -> {get_duckdb_cast_statement_from_annotation('x',element_type, False, date_regex, timestamp_regex)})"  # pylint: disable=C0301
+        return stmt if not parent_element else _cast_as_ddb_type(stmt, type_annotation)
+
+    if type_origin is Annotated:
+        python_type, *other_args = get_args(type_annotation)  # pylint: disable=unused-variable
+        return get_duckdb_cast_statement_from_annotation(
+            element_name, python_type, parent_element, date_regex, timestamp_regex
+        )  # add other expected params here
+    # Ensure that we have a concrete type at this point.
+    if not isinstance(type_annotation, type):
+        raise ValueError(f"Unsupported type annotation {type_annotation!r}")
+
+    if (
+        # Type hint is a dict subclass, but not dict. Possibly a `TypedDict`.
+        (issubclass(type_annotation, dict) and type_annotation is not dict)
+        # Type hint is a dataclass.
+        or is_dataclass(type_annotation)
+        # Type hint is a `pydantic` model.
+        or (type_origin is None and issubclass(type_annotation, BaseModel))
+    ):
+        fields: dict[str, str] = {}
+        for field_name, field_annotation in get_type_hints(type_annotation).items():
+            # Technically non-string keys are disallowed, but people are bad.
+            if not isinstance(field_name, str):
+                raise ValueError(
+                    f"Dictionary/Dataclass keys must be strings, got {type_annotation!r}"
+                )  # pragma: no cover
+            if get_origin(field_annotation) is ClassVar:
+                continue
+
+            fields[field_name] = get_duckdb_cast_statement_from_annotation(
+                f"{element_name}.{field_name}", field_annotation, False, date_regex, timestamp_regex
+            )
+
+        if not fields:
+            raise ValueError(
+                f"No type annotations in dict/dataclass type (got {type_annotation!r})"
+            )
+        cast_exprs = ",".join([f'"{nme}":= {stmt}' for nme, stmt in fields.items()])
+        stmt = f"struct_pack({cast_exprs})"
+        return stmt if not parent_element else _cast_as_ddb_type(stmt, type_annotation)
+
+    if type_annotation is list:
+        raise ValueError(
+            f"List must have type annotation (e.g. `List[str]`), got {type_annotation!r}"
+        )
+    if type_annotation is dict or type_origin is dict:
+        raise ValueError(f"dict must be `typing.TypedDict` subclass, got {type_annotation!r}")
+
+    for type_ in type_annotation.mro():
+        # datetime is subclass of date, so needs to be handled first
+        if issubclass(type_, datetime):
+            stmt = rf"CASE WHEN REGEXP_MATCHES(TRIM({quoted_name}), '{timestamp_regex}') THEN TRY_CAST(TRIM({quoted_name}) as TIMESTAMP) ELSE NULL END"  # pylint: disable=C0301
+            return stmt
+        if issubclass(type_, date):
+            stmt = rf"CASE WHEN REGEXP_MATCHES(TRIM({quoted_name}), '{date_regex}') THEN TRY_CAST(TRIM({quoted_name}) as DATE) ELSE NULL END"  # pylint: disable=C0301
+            return stmt
+        if issubclass(type_, time):
+            stmt = rf"CASE WHEN REGEXP_MATCHES(TRIM({quoted_name}), '{time_regex}') THEN TRY_CAST(TRIM({quoted_name}) as TIME) ELSE NULL END" # pylint: disable=C0301
+            return stmt
+        duck_type = get_duckdb_type_from_annotation(type_)
+        if duck_type:
+            stmt = f"trim({quoted_name})"
+            return _cast_as_ddb_type(stmt, type_) if parent_element else stmt
+    raise ValueError(f"No equivalent DuckDB type for {type_annotation!r}")

src/dve/core_engine/backends/implementations/duckdb/duckdb_helpers.py

@@ -439,3 +439,103 @@ def spark_record_index(cls):
     setattr(cls, "add_record_index", _add_spark_record_index)
     setattr(cls, "drop_record_index", _drop_spark_record_index)
     return cls
+
+
+def _cast_as_spark_type(field_expr: str, field_type: Any) -> Column:
+    """Cast to spark type"""
+    return sf.expr(field_expr).cast(get_type_from_annotation(field_type))
+
+
+def _spark_safely_quote_name(field_name: str) -> str:
+    """Quote field names in case reserved"""
+    try:
+        sep_idx = field_name.index(".")
+        return f"`{field_name[: sep_idx]}`" + field_name[sep_idx:]
+    except ValueError:
+        return f"`{field_name}`"
+
+
+# pylint: disable=R0801
+def get_spark_cast_statement_from_annotation(
+    element_name: str,
+    type_annotation: Any,
+    parent_element: bool = True,
+    date_regex: str = r"^[0-9]{4}-[0-9]{2}-[0-9]{2}$",
+    timestamp_regex: str = r"^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}((\\+|\\-)[0-9]{2}:[0-9]{2})?$",  # pylint: disable=C0301
+):
+    """Generate casting statements for spark dataframes based on type annotations"""
+    type_origin = get_origin(type_annotation)
+
+    quoted_name = _spark_safely_quote_name(element_name)
+
+    # An `Optional` or `Union` type, check to ensure non-heterogenity.
+    if type_origin is Union:
+        python_type = _get_non_heterogenous_type(get_args(type_annotation))
+        return get_spark_cast_statement_from_annotation(
+            element_name, python_type, parent_element, date_regex, timestamp_regex
+        )
+
+    # Type hint is e.g. `List[str]`, check to ensure non-heterogenity.
+    if type_origin is list or (isinstance(type_origin, type) and issubclass(type_origin, list)):
+        element_type = _get_non_heterogenous_type(get_args(type_annotation))
+        stmt = f"transform({quoted_name}, x -> {get_spark_cast_statement_from_annotation('x',element_type, False, date_regex, timestamp_regex)})"  # pylint: disable=C0301
+        return stmt if not parent_element else _cast_as_spark_type(stmt, type_annotation)
+
+    if type_origin is Annotated:
+        python_type, *_ = get_args(type_annotation)  # pylint: disable=unused-variable
+        return get_spark_cast_statement_from_annotation(
+            element_name, python_type, parent_element, date_regex, timestamp_regex
+        )  # add other expected params here
+    # Ensure that we have a concrete type at this point.
+    if not isinstance(type_annotation, type):
+        raise ValueError(f"Unsupported type annotation {type_annotation!r}")
+
+    if (
+        # Type hint is a dict subclass, but not dict. Possibly a `TypedDict`.
+        (issubclass(type_annotation, dict) and type_annotation is not dict)
+        # Type hint is a dataclass.
+        or is_dataclass(type_annotation)
+        # Type hint is a `pydantic` model.
+        or (type_origin is None and issubclass(type_annotation, BaseModel))
+    ):
+        fields: dict[str, str] = {}
+        for field_name, field_annotation in get_type_hints(type_annotation).items():
+            # Technically non-string keys are disallowed, but people are bad.
+            if not isinstance(field_name, str):
+                raise ValueError(
+                    f"Dictionary/Dataclass keys must be strings, got {type_annotation!r}"
+                )  # pragma: no cover
+            if get_origin(field_annotation) is ClassVar:
+                continue
+
+            fields[field_name] = get_spark_cast_statement_from_annotation(
+                f"{element_name}.{field_name}", field_annotation, False, date_regex, timestamp_regex
+            )
+
+        if not fields:
+            raise ValueError(
+                f"No type annotations in dict/dataclass type (got {type_annotation!r})"
+            )
+        cast_exprs = ",".join([f"{stmt} AS `{nme}`" for nme, stmt in fields.items()])
+        stmt = f"struct({cast_exprs})"
+        return stmt if not parent_element else _cast_as_spark_type(stmt, type_annotation)
+    if type_annotation is list:
+        raise ValueError(
+            f"List must have type annotation (e.g. `List[str]`), got {type_annotation!r}"
+        )
+    if type_annotation is dict or type_origin is dict:
+        raise ValueError(f"dict must be `typing.TypedDict` subclass, got {type_annotation!r}")
+
+    for type_ in type_annotation.mro():
+        # datetime is subclass of date, so needs to be handled first
+        if issubclass(type_, dt.datetime):
+            stmt = rf"CASE WHEN REGEXP(TRIM({quoted_name}), '{timestamp_regex}') THEN TRIM({quoted_name}) ELSE NULL END"  # pylint: disable=C0301
+            return _cast_as_spark_type(stmt, type_) if parent_element else stmt
+        if issubclass(type_, dt.date):
+            stmt = rf"CASE WHEN REGEXP(TRIM({quoted_name}), '{date_regex}') THEN TRIM({quoted_name}) ELSE NULL END"  # pylint: disable=C0301
+            return _cast_as_spark_type(stmt, type_) if parent_element else stmt
+        spark_type = get_type_from_annotation(type_)
+        if spark_type:
+            stmt = f"trim({quoted_name})"
+            return _cast_as_spark_type(stmt, type_) if parent_element else stmt
+    raise ValueError(f"No equivalent Spark type for {type_annotation!r}")

src/dve/core_engine/backends/implementations/spark/spark_helpers.py

@@ -519,7 +519,8 @@ def validate(cls, value: Union[dt.time, dt.datetime, str]) -> dt.time | None:
             raise ValueError("Provided time has timezone, but this is forbidden for this field")
         if cls.TIMEZONE_TREATMENT == "require" and not new_time.tzinfo:
             raise ValueError("Provided time missing timezone, but this is required for this field")
-
+        if isinstance(value, str) and cls.TIME_FORMAT and value != str(new_time):
+            raise ValueError("Provided time is not matching expected time format supplied.")
         return new_time
 
     @classmethod

src/dve/metadata_parser/domain_types.py

@@ -42,13 +42,13 @@ def persist_audit_records(self, submission_info: SubmissionInfo) -> URI:
             write_to.parent.mkdir(parents=True, exist_ok=True)
             write_to = write_to.as_posix()
         self.write_parquet(  # type: ignore # pylint: disable=E1101
-            self._audit_tables._processing_status.get_relation().filter( # pylint: disable=W0212
+            self._audit_tables._processing_status.get_relation().filter(  # pylint: disable=W0212
                 f"submission_id = '{submission_info.submission_id}'"
             ),
             fh.joinuri(write_to, "processing_status.parquet"),
         )
         self.write_parquet(  # type: ignore # pylint: disable=E1101
-            self._audit_tables._submission_statistics.get_relation().filter( # pylint: disable=W0212
+            self._audit_tables._submission_statistics.get_relation().filter(  # pylint: disable=W0212
                 f"submission_id = '{submission_info.submission_id}'"
             ),
             fh.joinuri(write_to, "submission_statistics.parquet"),