[SPARK-42929][CONNECT][FOLLOWUP] Rename isBarrier to barrier

### What changes were proposed in this pull request?

This is a follow-up of #40559 and #40571.

Renames `isBarrier` to `barrier` in Spark Connect, too.

### Why are the changes needed?

#40571 changed the argument name from `isBarrier` to `barrier`, so Spark Connect should follow it.

### Does this PR introduce _any_ user-facing change?

Yes, it renames the parameter.

### How was this patch tested?

Existing tests.

Closes #40579 from ueshin/issues/SPARK-42929/barrier.

Authored-by: Takuya UESHIN <ueshin@databricks.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>

connector/connect/common/src/main/protobuf/spark/connect/relations.proto

@@ -795,7 +795,7 @@ message MapPartitions {
   // (Required) Input user-defined function.
   CommonInlineUserDefinedFunction func = 2;
 
-  // (Optional) isBarrier.
+  // (Optional) Whether to use barrier mode execution or not.
   optional bool is_barrier = 3;
 }
 

python/pyspark/sql/connect/dataframe.py

@@ -1645,7 +1645,7 @@ def _map_partitions(
         func: "PandasMapIterFunction",
         schema: Union[StructType, str],
         evalType: int,
-        is_barrier: bool,
+        barrier: bool,
     ) -> "DataFrame":
         from pyspark.sql.connect.udf import UserDefinedFunction
 
@@ -1660,7 +1660,7 @@ def _map_partitions(
 
         return DataFrame.withPlan(
             plan.MapPartitions(
-                child=self._plan, function=udf_obj, cols=self.columns, is_barrier=is_barrier
+                child=self._plan, function=udf_obj, cols=self.columns, is_barrier=barrier
             ),
             session=self._session,
         )
@@ -1669,21 +1669,19 @@ def mapInPandas(
         self,
         func: "PandasMapIterFunction",
         schema: Union[StructType, str],
-        is_barrier: bool = False,
+        barrier: bool = False,
     ) -> "DataFrame":
-        return self._map_partitions(
-            func, schema, PythonEvalType.SQL_MAP_PANDAS_ITER_UDF, is_barrier
-        )
+        return self._map_partitions(func, schema, PythonEvalType.SQL_MAP_PANDAS_ITER_UDF, barrier)
 
     mapInPandas.__doc__ = PySparkDataFrame.mapInPandas.__doc__
 
     def mapInArrow(
         self,
         func: "ArrowMapIterFunction",
         schema: Union[StructType, str],
-        is_barrier: bool = False,
+        barrier: bool = False,
     ) -> "DataFrame":
-        return self._map_partitions(func, schema, PythonEvalType.SQL_MAP_ARROW_ITER_UDF, is_barrier)
+        return self._map_partitions(func, schema, PythonEvalType.SQL_MAP_ARROW_ITER_UDF, barrier)
 
     mapInArrow.__doc__ = PySparkDataFrame.mapInArrow.__doc__
 

python/pyspark/sql/connect/proto/relations_pb2.pyi

@@ -2767,7 +2767,7 @@ class MapPartitions(google.protobuf.message.Message):
     def func(self) -> pyspark.sql.connect.proto.expressions_pb2.CommonInlineUserDefinedFunction:
         """(Required) Input user-defined function."""
     is_barrier: builtins.bool
-    """(Optional) isBarrier."""
+    """(Optional) Whether to use barrier mode execution or not."""
     def __init__(
         self,
         *,