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fix: connectedComponents max_iter default evaluated to 31 due to ^ precedence #902

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Merged
SemyonSinchenko merged 1 commit into from
Sep 13, 2026
Merged

fix: connectedComponents max_iter default evaluated to 31 due to ^ precedence #902

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5 changes: 4 additions & 1 deletion python/graphframes/graphframe.py
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Original file line number Diff line number Diff line change
Expand Up @@ -661,7 +661,7 @@ def connectedComponents(
broadcastThreshold: int = 1000000,
useLabelsAsComponents: bool = False,
use_local_checkpoints: bool = False,
max_iter: int = 2 ^ 31 - 2,
max_iter: int = 2**31 - 2,
storage_level: StorageLevel = StorageLevel.MEMORY_AND_DISK_DESER,
) -> DataFrame:
"""
Expand All @@ -685,6 +685,9 @@ def connectedComponents(
a persistent checkpointDir; from the other side, local
checkpoints are less reliable and require executors to have
big enough local disks.
:param max_iter: maximum number of Pregel supersteps, only used when the algorithm is
"graphx" (default: 2 ** 31 - 2, that is effectively unlimited). The
other algorithms run until convergence and ignore this value.
:param storage_level: storage level for both intermediate and final dataframes.

:return: DataFrame with new vertices column "component"
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23 changes: 23 additions & 0 deletions python/tests/test_graphframes.py
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
#


import inspect
from dataclasses import dataclass

import pytest
Expand Down Expand Up @@ -644,6 +645,28 @@ def test_connected_components_example(spark: SparkSession) -> None:
_ = cc.unpersist()


def test_connected_components_graphx_default_max_iter_is_unlimited(spark: SparkSession) -> None:
"""Regression: the default `2 ^ 31 - 2` is XOR and evaluated to 31, truncating GraphX."""
n = 50
v = spark.createDataFrame([(i,) for i in range(n)], ["id"])
e = spark.createDataFrame([(i, i + 1) for i in range(n - 1)], ["src", "dst"])
g = GraphFrame(v, e)

# max_iter is deliberately not passed: this exercises the default. The path graph has
# diameter n - 1 = 49, so a default capped at 31 supersteps splits it into 19 components.
result = g.connectedComponents(algorithm="graphx")
assert result.count() == n
assert result.select("component").distinct().count() == 1

_ = result.unpersist()


def test_connected_components_max_iter_default_value() -> None:
"""Guard the default itself so a `**` -> `^` regression fails without starting Spark."""
default = inspect.signature(GraphFrame.connectedComponents).parameters["max_iter"].default
assert default == 2**31 - 2


@pytest.mark.parametrize("args", PREGEL_ARGUMENTS, ids=PREGEL_IDS)
def test_shortest_paths(spark: SparkSession, args: PregelArguments) -> None:
edges = [(1, 2), (1, 5), (2, 3), (2, 5), (3, 4), (4, 5), (4, 6)]
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