Add reset metadata origin option (#3731)

* ✨ Add reset_metadata paramter to .load

* wip

* wip

* adding option to keep origin

* Mojmirs suggestions

---------

Co-authored-by: Marigold <mojmir.vinkler@gmail.com>

lib/catalog/owid/catalog/datasets.py

@@ -21,7 +21,7 @@
 from owid.repack import to_safe_types
 
 from . import tables, utils
-from .meta import SOURCE_EXISTS_OPTIONS, DatasetMeta, TableMeta
+from .meta import SOURCE_EXISTS_OPTIONS, DatasetMeta, TableMeta, VariableMeta
 from .processing_log import disable_processing_log
 from .properties import metadata_property
 
@@ -155,14 +155,24 @@ def add(
             table_filename = join(self.path, table.metadata.checked_name + f".{format}")
             table.to(table_filename, repack=repack)
 
-    def read(self, name: str, reset_index: bool = True, safe_types: bool = True) -> tables.Table:
+    def read(
+        self,
+        name: str,
+        reset_index: bool = True,
+        safe_types: bool = True,
+        reset_metadata: Literal["keep", "keep_origins", "reset"] = "keep",
+    ) -> tables.Table:
         """Read dataset's table from disk. Alternative to ds[table_name], but
         with more options to optimize the reading.
 
         :param reset_index: If true, don't set primary keys of the table. This can make loading
             large datasets with multi-indexes much faster.
         :param safe_types: If true, convert numeric columns to Float64 and Int64 and categorical
             columns to string[pyarrow]. This can significantly increase memory usage.
+        :param reset_metadata: Controls variable metadata reset behavior.
+            - "keep": Leave metadata unchanged (default).
+            - "keep_origins": Reset variable metadata but retain the 'origins' attribute.
+            - "reset": Reset all variable metadata.
         """
         stem = self.path / Path(name)
 
@@ -173,6 +183,15 @@ def read(self, name: str, reset_index: bool = True, safe_types: bool = True) ->
                 t.metadata.dataset = self.metadata
                 if safe_types:
                     t = cast(tables.Table, to_safe_types(t))
+                if reset_metadata in ["keep_origins", "reset"]:  # Handles "keep_origins" and "reset"
+                    t.metadata = TableMeta()
+                    for col in t.columns:
+                        if reset_metadata == "keep_origins":  # Preserve 'origins' attribute
+                            origins = t[col].metadata.origins if hasattr(t[col].metadata, "origins") else None
+                            t[col].metadata = VariableMeta()
+                            t[col].metadata.origins = origins  # Preserve 'origins' attribute
+                        if reset_metadata == "reset":  # Reset all metadata
+                            t[col].metadata = VariableMeta()
                 return t
 
         raise KeyError(f"Table `{name}` not found, available tables: {', '.join(self.table_names)}")