(arrow) branch main updated: GH-51018: [C++] Fix indices_nonzero segfault on chunkless ChunkedArray (#51021)

[rok]

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The following commit(s) were added to refs/heads/main by this push:
     new c4a0850ebf9 GH-51018: [C++] Fix indices_nonzero segfault on chunkless 
ChunkedArray (#51021)
c4a0850ebf9 is described below

commit c4a0850ebf9e800cf4dd453476a22051257f3ed6
Author: water <672684...@qq.com>
AuthorDate: Tue Oct 13 18:39:15 2026 +0800

    GH-51018: [C++] Fix indices_nonzero segfault on chunkless ChunkedArray 
(#51021)
    
    ### Rationale for this change
    
    `pyarrow.compute.indices_nonzero()` segfaults (SIGSEGV) on a `ChunkedArray` 
with zero chunks. A zero-length `Array` and a `ChunkedArray` holding one empty 
chunk both work; only the chunkless case crashes.
    
    ### Are these changes tested?
    
    Yes, by new test case.
    
    ### Are there any user-facing changes?
    
    Only a bugfix.
    
    * GitHub Issue: #51018
    
    Authored-by: waterWang <waterw...@users.noreply.github.com>
    Signed-off-by: Rok Mihevc <r...@mihevc.org>
---
 cpp/src/arrow/compute/kernels/vector_selection.cc      | 6 ++++--
 cpp/src/arrow/compute/kernels/vector_selection_test.cc | 8 ++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/cpp/src/arrow/compute/kernels/vector_selection.cc 
b/cpp/src/arrow/compute/kernels/vector_selection.cc
index 6f8dd52a4fd..687e0d93392 100644
--- a/cpp/src/arrow/compute/kernels/vector_selection.cc
+++ b/cpp/src/arrow/compute/kernels/vector_selection.cc
@@ -264,8 +264,10 @@ Status DoNonZero(const std::vector<ArraySpan>& arrays, 
int64_t total_length,
   UInt64Builder builder;
   RETURN_NOT_OK(builder.Reserve(total_length));
 
-  NonZeroVisitor visitor(&builder, arrays);
-  RETURN_NOT_OK(VisitTypeInline(*arrays[0].type, &visitor));
+  if (!arrays.empty()) {
+    NonZeroVisitor visitor(&builder, arrays);
+    RETURN_NOT_OK(VisitTypeInline(*arrays[0].type, &visitor));
+  }
   return builder.FinishInternal(out);
 }
 
diff --git a/cpp/src/arrow/compute/kernels/vector_selection_test.cc 
b/cpp/src/arrow/compute/kernels/vector_selection_test.cc
index c7972098539..5e38ac15306 100644
--- a/cpp/src/arrow/compute/kernels/vector_selection_test.cc
+++ b/cpp/src/arrow/compute/kernels/vector_selection_test.cc
@@ -2920,6 +2920,14 @@ TEST(TestIndicesNonZero, IndicesNonZero) {
         actual, CallFunction("indices_nonzero", 
{static_cast<Datum>(chunked_arr_empty)}));
     AssertArraysEqual(*ArrayFromJSON(uint64(), "[0, 2, 3, 5]"), 
*actual.make_array(),
                       /*verbose*/ true);
+
+    // chunked with zero chunks (GH-51018)
+    ChunkedArray chunked_arr_no_chunks({}, type);
+    ASSERT_OK_AND_ASSIGN(
+        actual,
+        CallFunction("indices_nonzero", 
{static_cast<Datum>(chunked_arr_no_chunks)}));
+    AssertArraysEqual(*ArrayFromJSON(uint64(), "[]"), *actual.make_array(),
+                      /*verbose*/ true);
   }
 }