source and schema changes (dlt-hub#769)

* add schema ancestors

* remove name attribute and init arg from dltsource

* fix 2 tests

* fix statekey related errors

* pr fixes

* revert changes on validate dict

* fix one test

dlt/common/schema/schema.py

@@ -44,6 +44,7 @@ class Schema:
     _dlt_tables_prefix: str
     _stored_version: int  # version at load/creation time
     _stored_version_hash: str  # version hash at load/creation time
+    _stored_previous_hashes: Optional[List[str]] # list of ancestor hashes of the schema
     _imported_version_hash: str  # version hash of recently imported schema
     _schema_description: str  # optional schema description
     _schema_tables: TSchemaTables
@@ -101,7 +102,8 @@ def to_dict(self, remove_defaults: bool = False, bump_version: bool = True) -> T
             "name": self._schema_name,
             "tables": self._schema_tables,
             "settings": self._settings,
-            "normalizers": self._normalizers_config
+            "normalizers": self._normalizers_config,
+            "previous_hashes": self._stored_previous_hashes
         }
         if self._imported_version_hash and not remove_defaults:
             stored_schema["imported_version_hash"] = self._imported_version_hash
@@ -353,7 +355,7 @@ def bump_version(self) -> Tuple[int, str]:
         Returns:
             Tuple[int, str]: Current (``stored_version``, ``stored_version_hash``) tuple
         """
-        self._stored_version, self._stored_version_hash, _ = utils.bump_version_if_modified(self.to_dict(bump_version=False))
+        self._stored_version, self._stored_version_hash, _, _ = utils.bump_version_if_modified(self.to_dict(bump_version=False))
         return self._stored_version, self._stored_version_hash
 
     def filter_row_with_hint(self, table_name: str, hint_type: TColumnHint, row: StrAny) -> StrAny:
@@ -475,6 +477,11 @@ def version_hash(self) -> str:
         """Current version hash of the schema, recomputed from the actual content"""
         return utils.bump_version_if_modified(self.to_dict())[1]
 
+    @property
+    def previous_hashes(self) -> List[str]:
+        """Current version hash of the schema, recomputed from the actual content"""
+        return utils.bump_version_if_modified(self.to_dict())[3]
+
     @property
     def stored_version_hash(self) -> str:
         """Version hash of the schema content form the time of schema loading/creation."""
@@ -663,6 +670,7 @@ def _reset_schema(self, name: str, normalizers: TNormalizersConfig = None) -> No
         self._stored_version_hash: str = None
         self._imported_version_hash: str = None
         self._schema_description: str = None
+        self._stored_previous_hashes: List[str] = []
 
         self._settings: TSchemaSettings = {}
         self._compiled_preferred_types: List[Tuple[REPattern, TDataType]] = []
@@ -701,6 +709,7 @@ def _from_stored_schema(self, stored_schema: TStoredSchema) -> None:
         self._imported_version_hash = stored_schema.get("imported_version_hash")
         self._schema_description = stored_schema.get("description")
         self._settings = stored_schema.get("settings") or {}
+        self._stored_previous_hashes = stored_schema.get("previous_hashes")
         self._compile_settings()
 
     def _set_schema_name(self, name: str) -> None:

dlt/common/schema/typing.py

@@ -11,7 +11,7 @@
 
 
 # current version of schema engine
-SCHEMA_ENGINE_VERSION = 7
+SCHEMA_ENGINE_VERSION = 8
 
 # dlt tables
 VERSION_TABLE_NAME = "_dlt_version"
@@ -123,6 +123,7 @@ class TStoredSchema(TypedDict, total=False):
     """TypeDict defining the schema representation in storage"""
     version: int
     version_hash: str
+    previous_hashes: List[str]
     imported_version_hash: Optional[str]
     engine_version: int
     name: str

dlt/common/schema/utils.py

@@ -134,7 +134,7 @@ def add_column_defaults(column: TColumnSchemaBase) -> TColumnSchema:
 #     return copy(column)  # type: ignore
 
 
-def bump_version_if_modified(stored_schema: TStoredSchema) -> Tuple[int, str, str]:
+def bump_version_if_modified(stored_schema: TStoredSchema) -> Tuple[int, str, str, List[str]]:
     """Bumps the `stored_schema` version and version hash if content modified, returns (new version, new hash, old hash) tuple"""
     hash_ = generate_version_hash(stored_schema)
     previous_hash = stored_schema.get("version_hash")
@@ -143,8 +143,13 @@ def bump_version_if_modified(stored_schema: TStoredSchema) -> Tuple[int, str, st
         pass
     elif hash_ != previous_hash:
         stored_schema["version"] += 1
+        # unshift previous hash to previous_hashes and limit array to 10 entries
+        if previous_hash not in stored_schema["previous_hashes"]:
+            stored_schema["previous_hashes"].insert(0, previous_hash)
+            stored_schema["previous_hashes"] = stored_schema["previous_hashes"][:10]
+
     stored_schema["version_hash"] = hash_
-    return stored_schema["version"], hash_, previous_hash
+    return stored_schema["version"], hash_, previous_hash, stored_schema["previous_hashes"]
 
 
 def generate_version_hash(stored_schema: TStoredSchema) -> str:
@@ -153,6 +158,7 @@ def generate_version_hash(stored_schema: TStoredSchema) -> str:
     schema_copy.pop("version")
     schema_copy.pop("version_hash", None)
     schema_copy.pop("imported_version_hash", None)
+    schema_copy.pop("previous_hashes", None)
     # ignore order of elements when computing the hash
     content = json.dumps(schema_copy, sort_keys=True)
     h = hashlib.sha3_256(content.encode("utf-8"))
@@ -240,6 +246,7 @@ def compile_simple_regexes(r: Iterable[TSimpleRegex]) -> REPattern:
 
 
 def validate_stored_schema(stored_schema: TStoredSchema) -> None:
+
     # use lambda to verify only non extra fields
     validate_dict_ignoring_xkeys(
         spec=TStoredSchema,
@@ -256,6 +263,7 @@ def validate_stored_schema(stored_schema: TStoredSchema) -> None:
 
 
 def migrate_schema(schema_dict: DictStrAny, from_engine: int, to_engine: int) -> TStoredSchema:
+
     if from_engine == to_engine:
         return cast(TStoredSchema, schema_dict)
 
@@ -349,6 +357,9 @@ def migrate_filters(group: str, filters: List[str]) -> None:
             if not table.get("parent"):
                 table["schema_contract"] = {}
         from_engine = 7
+    if from_engine == 7 and to_engine > 7:
+        schema_dict["previous_hashes"] = []
+        from_engine = 8
 
     schema_dict["engine_version"] = from_engine
     if from_engine != to_engine:

dlt/common/validation.py

@@ -22,6 +22,8 @@ def validate_dict(spec: Type[_TypedDict], doc: StrAny, path: str, filter_f: TFil
         validator_f (TCustomValidator, optional): A function to perform additional validation
             for types not covered by this function. It should return `True` if the validation passes.
             Defaults to a function that rejects all such types.
+        filter_required (TFilterFunc, optional): A function to filter out required fields, useful
+            for testing historic versions of dict that might now have certain fields yet.
 
     Raises:
         DictValidationException: If there are missing required fields, unexpected fields,

dlt/extract/decorators.py

@@ -150,9 +150,6 @@ def decorator(f: Callable[TSourceFunParams, Any]) -> Callable[TSourceFunParams,
         if name and name != schema.name:
             raise ExplicitSourceNameInvalid(name, schema.name)
 
-        # the name of the source must be identical to the name of the schema
-        name = schema.name
-
         # wrap source extraction function in configuration with section
         func_module = inspect.getmodule(f)
         source_section = section or _get_source_section_name(func_module)
@@ -167,16 +164,16 @@ def _wrap(*args: Any, **kwargs: Any) -> TDltSourceImpl:
                 # configurations will be accessed in this section in the source
                 proxy = Container()[PipelineContext]
                 pipeline_name = None if not proxy.is_active() else proxy.pipeline().pipeline_name
-                with inject_section(ConfigSectionContext(pipeline_name=pipeline_name, sections=source_sections, source_state_key=name)):
+                with inject_section(ConfigSectionContext(pipeline_name=pipeline_name, sections=source_sections, source_state_key=schema.name)):
                     rv = conf_f(*args, **kwargs)
                     if rv is None:
-                        raise SourceDataIsNone(name)
+                        raise SourceDataIsNone(schema.name)
                     # if generator, consume it immediately
                     if inspect.isgenerator(rv):
                         rv = list(rv)
 
             # convert to source
-            s = _impl_cls.from_data(name, source_section, schema.clone(update_normalizers=True), rv)
+            s = _impl_cls.from_data(schema.clone(update_normalizers=True), source_section, rv)
             # apply hints
             if max_table_nesting is not None:
                 s.max_table_nesting = max_table_nesting

dlt/extract/source.py

@@ -167,22 +167,17 @@ class DltSource(Iterable[TDataItem]):
     * You can use a `run` method to load the data with a default instance of dlt pipeline.
     * You can get source read only state for the currently active Pipeline instance
     """
-    def __init__(self, name: str, section: str, schema: Schema, resources: Sequence[DltResource] = None) -> None:
-        self.name = name
+    def __init__(self, schema: Schema, section: str, resources: Sequence[DltResource] = None) -> None:
         self.section = section
         """Tells if iterator associated with a source is exhausted"""
         self._schema = schema
         self._resources: DltResourceDict = DltResourceDict(self.name, self.section)
 
-        if self.name != schema.name:
-            # raise ValueError(f"Schema name {schema.name} differs from source name {name}! The explicit source name argument is deprecated and will be soon removed.")
-            warnings.warn(f"Schema name {schema.name} differs from source name {name}! The explicit source name argument is deprecated and will be soon removed.")
-
         if resources:
             self.resources.add(*resources)
 
     @classmethod
-    def from_data(cls, name: str, section: str, schema: Schema, data: Any) -> Self:
+    def from_data(cls, schema: Schema, section: str, data: Any) -> Self:
         """Converts any `data` supported by `dlt` `run` method into `dlt source` with a name `section`.`name` and `schema` schema."""
         # creates source from various forms of data
         if isinstance(data, DltSource):
@@ -194,10 +189,14 @@ def from_data(cls, name: str, section: str, schema: Schema, data: Any) -> Self:
         else:
             resources = [DltResource.from_data(data)]
 
-        return cls(name, section, schema, resources)
+        return cls(schema, section, resources)
 
-    # TODO: 4 properties below must go somewhere else ie. into RelationalSchema which is Schema + Relational normalizer.
+    @property
+    def name(self) -> str:
+        return self._schema.name
 
+
+    # TODO: 4 properties below must go somewhere else ie. into RelationalSchema which is Schema + Relational normalizer.
     @property
     def max_table_nesting(self) -> int:
         """A schema hint that sets the maximum depth of nested table above which the remaining nodes are loaded as structs or JSON."""
@@ -328,7 +327,7 @@ def state(self) -> StrAny:
     def clone(self) -> "DltSource":
         """Creates a deep copy of the source where copies of schema, resources and pipes are created"""
         # mind that resources and pipes are cloned when added to the DltResourcesDict in the source constructor
-        return DltSource(self.name, self.section, self.schema.clone(), list(self._resources.values()))
+        return DltSource(self.schema.clone(), self.section, list(self._resources.values()))
 
     def __iter__(self) -> Iterator[TDataItem]:
         """Opens iterator that yields the data items from all the resources within the source in the same order as in Pipeline class.

dlt/pipeline/pipeline.py

@@ -860,7 +860,7 @@ def append_data(data_item: Any) -> None:
                 # do not set section to prevent source that represent a standalone resource
                 # to overwrite other standalone resources (ie. parents) in that source
                 sources.append(
-                    DltSource(effective_schema.name, "", effective_schema, [data_item])
+                    DltSource(effective_schema, "", [data_item])
                     )
             else:
                 # iterator/iterable/generator
@@ -881,7 +881,7 @@ def append_data(data_item: Any) -> None:
 
         # add all the appended resources in one source
         if resources:
-            sources.append(DltSource(effective_schema.name, self.pipeline_name, effective_schema, resources))
+            sources.append(DltSource(effective_schema, self.pipeline_name, resources))
 
         # apply hints and settings
         for source in sources:
@@ -1293,7 +1293,7 @@ def _save_state(self, state: TPipelineState) -> None:
     def _extract_state(self, state: TPipelineState) -> TPipelineState:
         # this will extract the state into current load package and update the schema with the _dlt_pipeline_state table
         # note: the schema will be persisted because the schema saving decorator is over the state manager decorator for extract
-        state_source = DltSource(self.default_schema.name, self.pipeline_name, self.default_schema, [state_resource(state)])
+        state_source = DltSource(self.default_schema, self.pipeline_name, [state_resource(state)])
         storage = ExtractorStorage(self._normalize_storage_config)
         extract_id = extract_with_schema(storage, state_source, _NULL_COLLECTOR, 1, 1)
         storage.commit_extract_files(extract_id)