From 32413d33c0a156b307eee75fd3f7e706df208b6a Mon Sep 17 00:00:00 2001
From: Krisztian Szucs <szucs.krisztian@gmail.com>
Date: Tue, 17 Dec 2024 10:08:08 +0100
Subject: [PATCH] use resize instead of reserve

---
 cpp/src/arrow/compute/kernels/scalar_hash.cc  |  2 +-
 .../arrow/compute/kernels/scalar_hash_test.cc | 40 +++++++++++++++++--
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/cpp/src/arrow/compute/kernels/scalar_hash.cc b/cpp/src/arrow/compute/kernels/scalar_hash.cc
index 554669abedeed..9dcfe16c3331e 100644
--- a/cpp/src/arrow/compute/kernels/scalar_hash.cc
+++ b/cpp/src/arrow/compute/kernels/scalar_hash.cc
@@ -120,7 +120,7 @@ struct FastHashScalar {
 
     if (type_id == Type::STRUCT) {
       std::vector<std::shared_ptr<ArrayData>> child_hashes(array.child_data.size());
-      columns.reserve(array.child_data.size());
+      columns.resize(array.child_data.size());
       for (size_t i = 0; i < array.child_data.size(); i++) {
         auto child = array.child_data[i];
         if (is_nested(child.type->id())) {
diff --git a/cpp/src/arrow/compute/kernels/scalar_hash_test.cc b/cpp/src/arrow/compute/kernels/scalar_hash_test.cc
index a2a2ce1ab69ab..f0aa13ff3339a 100644
--- a/cpp/src/arrow/compute/kernels/scalar_hash_test.cc
+++ b/cpp/src/arrow/compute/kernels/scalar_hash_test.cc
@@ -268,7 +268,7 @@ TEST_F(TestScalarHash, RandomNumericLike) {
   }
 }
 
-TEST_F(TestScalarHash, RandomNested) {
+TEST_F(TestScalarHash, RandomList) {
   auto rand = random::RandomArrayGenerator(kSeed);
   auto types = {
       list(int32()),
@@ -282,9 +282,22 @@ TEST_F(TestScalarHash, RandomNested) {
       list(list(int16())),
       list(list(list(uint8()))),
       fixed_size_list(int32(), 3),
-      map(int32(), int32()),
-      map(int32(), utf8()),
-      map(utf8(), list(int16())),
+  };
+  for (auto type : types) {
+    for (auto length : array_lengths) {
+      for (auto null_probability : null_probabilities) {
+        auto arr = rand.ArrayOf(type, length, null_probability);
+        CheckDeterminisic("hash32", arr);
+        CheckDeterminisic("hash64", arr);
+      }
+    }
+  }
+}
+
+TEST_F(TestScalarHash, RandomStruct) {
+  auto rand = random::RandomArrayGenerator(kSeed);
+  auto types = {
+      struct_({field("f0", int32())}),
       struct_({field("f0", int32()), field("f1", utf8())}),
       struct_({field("f0", list(int32()))}),
       struct_({field("f0", struct_({field("f0", int32()), field("f1", utf8())}))}),
@@ -300,5 +313,24 @@ TEST_F(TestScalarHash, RandomNested) {
   }
 }
 
+TEST_F(TestScalarHash, RandomMap) {
+  auto rand = random::RandomArrayGenerator(kSeed);
+  auto types = {
+      map(int32(), int32()),
+      map(int32(), utf8()),
+      map(utf8(), list(int16())),
+      map(utf8(), map(int32(), int32())),
+  };
+  for (auto type : types) {
+    for (auto length : array_lengths) {
+      for (auto null_probability : null_probabilities) {
+        auto arr = rand.ArrayOf(type, length, null_probability);
+        CheckDeterminisic("hash32", arr);
+        CheckDeterminisic("hash64", arr);
+      }
+    }
+  }
+}
+
 }  // namespace compute
 }  // namespace arrow