[iceberg] branch master updated: Python: TypeVar for bounding TableScan (#6819)

[fo...@apache.org]

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fokko pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/iceberg.git


The following commit(s) were added to refs/heads/master by this push:
     new 96dc0c6a6e Python: TypeVar for bounding TableScan (#6819)
96dc0c6a6e is described below

commit 96dc0c6a6e2be2f32714acba94299511b8948e95
Author: Guillem Orellana Trullols <gu...@gmail.com>
AuthorDate: Mon Feb 13 16:51:19 2023 +0100

    Python: TypeVar for bounding TableScan (#6819)
    
    * Properly use TypeVar for bounding TableScan return
    
    * Fix isort and mypy error
    
    * Update __init__.py
    
    ---------
    
    Co-authored-by: Fokko Driesprong <fo...@apache.org>
---
 python/pyiceberg/table/__init__.py | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/python/pyiceberg/table/__init__.py b/python/pyiceberg/table/__init__.py
index dc9cc9e036..df2e09ab3a 100644
--- a/python/pyiceberg/table/__init__.py
+++ b/python/pyiceberg/table/__init__.py
@@ -26,7 +26,6 @@ from typing import (
     Any,
     Callable,
     Dict,
-    Generic,
     Iterator,
     List,
     Optional,
@@ -101,7 +100,7 @@ class Table:
         case_sensitive: bool = True,
         snapshot_id: Optional[int] = None,
         options: Properties = EMPTY_DICT,
-    ) -> TableScan[Any]:
+    ) -> DataScan:
         return DataScan(
             table=self,
             row_filter=row_filter,
@@ -174,9 +173,6 @@ class Table:
         )
 
 
-S = TypeVar("S", bound="TableScan", covariant=True)  # type: ignore
-
-
 def _parse_row_filter(expr: Union[str, BooleanExpression]) -> BooleanExpression:
     """Accepts an expression in the form of a BooleanExpression or a string
 
@@ -190,7 +186,10 @@ def _parse_row_filter(expr: Union[str, BooleanExpression]) -> BooleanExpression:
     return parser.parse(expr) if isinstance(expr, str) else expr
 
 
-class TableScan(Generic[S], ABC):
+S = TypeVar("S", bound="TableScan", covariant=True)
+
+
+class TableScan(ABC):
     table: Table
     row_filter: BooleanExpression
     selected_fields: Tuple[str]
@@ -246,7 +245,7 @@ class TableScan(Generic[S], ABC):
         """Creates a copy of this table scan with updated fields."""
         return type(self)(**{**self.__dict__, **overrides})
 
-    def use_ref(self, name: str) -> S:
+    def use_ref(self: S, name: str) -> S:
         if self.snapshot_id:
             raise ValueError(f"Cannot override ref, already set snapshot id={self.snapshot_id}")
         if snapshot := self.table.snapshot_by_name(name):
@@ -254,15 +253,15 @@ class TableScan(Generic[S], ABC):
 
         raise ValueError(f"Cannot scan unknown ref={name}")
 
-    def select(self, *field_names: str) -> S:
+    def select(self: S, *field_names: str) -> S:
         if "*" in self.selected_fields:
             return self.update(selected_fields=field_names)
         return self.update(selected_fields=tuple(set(self.selected_fields).intersection(set(field_names))))
 
-    def filter(self, expr: Union[str, BooleanExpression]) -> S:
+    def filter(self: S, expr: Union[str, BooleanExpression]) -> S:
         return self.update(row_filter=And(self.row_filter, _parse_row_filter(expr)))
 
-    def with_case_sensitive(self, case_sensitive: bool = True) -> S:
+    def with_case_sensitive(self: S, case_sensitive: bool = True) -> S:
         return self.update(case_sensitive=case_sensitive)
 
 
@@ -299,7 +298,7 @@ def _open_manifest(io: FileIO, manifest: ManifestFile, partition_filter: Callabl
     return [FileScanTask(file) for file in matching_partition_data_files]
 
 
-class DataScan(TableScan["DataScan"]):
+class DataScan(TableScan):
     def __init__(
         self,
         table: Table,