fix(search): reject FT.CREATE NUMERIC BLOCKSIZE 0 (divide-by-zero) (#8164)

Author: vyavdoshenko

src/core/search/range_tree.cc

@@ -76,7 +76,10 @@ template <typename MapT> auto FindRangeBlockImpl(MapT& entries, double value) {
 }  // namespace
 
 RangeTree::RangeTree(PMR_NS::memory_resource* mr, size_t max_range_block_size)
-    : max_range_block_size_(max_range_block_size), entries_(mr) {
+    // A zero block size is used as a divisor in Builder::Populate; fall back to the default.
+    : max_range_block_size_(max_range_block_size ? max_range_block_size
+                                                 : kDefaultMaxRangeBlockSize),
+      entries_(mr) {
   // The tree has at least always a block with a negative infinity bound, so that any new insertion
   // goes at least somewhere
   CreateEmptyBlock(-std::numeric_limits<double>::infinity());

src/core/search/range_tree_test.cc

@@ -628,6 +628,24 @@ TEST_F(RangeTreeTest, DiscreteIntialization) {
   EXPECT_EQ(result.size(), 4u);
 }
 
+TEST_F(BuilderTest, ZeroBlockSizeDoesNotDivideByZero) {
+  RangeTree tree{PMR_NS::get_default_resource(), 0};
+  RangeTree::Builder builder;
+
+  std::vector<RangeTree::Entry> entries;
+  entries.reserve(20);
+  for (size_t i = 0; i < 20; i++)
+    entries.emplace_back(i, double(i));
+  for (auto [id, v] : entries)
+    builder.Add(id, v);
+
+  builder.Populate(&tree, RenewableQuota::Unlimited());
+
+  rng::sort(entries, {}, &RangeTree::Entry::first);
+  auto all_values = tree.Range(-1000, +1000);
+  EXPECT_TRUE(rng::equal(all_values.Take(), entries | std::views::keys));
+}
+
 // Benchmark tree insertion performance with set of discrete values
 static void BM_DiscreteInsertion(benchmark::State& state) {
   RangeTree tree{PMR_NS::get_default_resource()};

src/server/search/search_family.cc

@@ -204,7 +204,10 @@ constexpr auto kTextParamsGrammar =
 
 search::SchemaField::NumericParams ParseNumericParams(CmdArgParser* parser) {
   search::SchemaField::NumericParams params{};
-  parser->Check("BLOCKSIZE", &params.block_size);
+  // A zero block size divides by zero when the numeric range tree is built.
+  if (parser->Check("BLOCKSIZE"))
+    params.block_size =
+        parser->Next<facade::Positive<size_t>>("BLOCKSIZE must be a positive integer");
   return params;
 }
 

src/server/search/search_family_test.cc

@@ -4074,6 +4074,18 @@ TEST_F(SearchFamilyTest, BlockSizeOptionFtCreate) {
   EXPECT_THAT(resp, AreDocIds("doc:1", "doc:2", "doc:3"));
 }
 
+TEST_F(SearchFamilyTest, BlockSizeZeroRejected) {
+  Run({"HSET", "doc:a", "n", "7"});
+
+  EXPECT_THAT(Run({"FT.CREATE", "idx0", "ON", "HASH", "PREFIX", "1", "doc:", "SCHEMA", "n",
+                   "NUMERIC", "BLOCKSIZE", "0"}),
+              ErrArg("BLOCKSIZE"));
+
+  EXPECT_THAT(Run({"FT.CREATE", "idx1", "ON", "HASH", "PREFIX", "1", "doc:", "SCHEMA", "n",
+                   "NUMERIC", "BLOCKSIZE", "1"}),
+              "OK");
+}
+
 TEST_F(SearchFamilyTest, AggregateWithLoadFromJoinSimple) {
   Run({"ft.create", "idx1", "ON", "HASH", "SCHEMA", "num1", "NUMERIC", "num2", "NUMERIC"});
   Run({"ft.create", "idx2", "ON", "HASH", "SCHEMA", "num3", "NUMERIC", "num4", "NUMERIC"});