fix: interted index out of range (#38577)

issue: #38546, #38486

Signed-off-by: chyezh <chyezh@outlook.com>

internal/core/src/index/InvertedIndexUtil.h

@@ -21,6 +21,18 @@ apply_hits(milvus::TargetBitmap& bitset,
     }
 }
 
+inline size_t
+should_allocate_bitset_size(const milvus::index::RustArrayWrapper& w) {
+    if (w.array_.len == 0) {
+        return 0;
+    }
+    size_t cnt = 0;
+    for (size_t i = 0; i < w.array_.len; i++) {
+        cnt = std::max(cnt, static_cast<size_t>(w.array_.array[i]));
+    }
+    return cnt + 1;
+}
+
 inline void
 apply_hits_with_filter(milvus::TargetBitmap& bitset,
                        const milvus::index::RustArrayWrapper& w,

internal/core/src/index/TextMatchIndex.cpp

@@ -246,12 +246,12 @@ TextMatchIndex::MatchQuery(const std::string& query) {
         Reload();
     }
 
-    auto cnt = wrapper_->count();
+    auto hits = wrapper_->match_query(query);
+    auto cnt = should_allocate_bitset_size(hits);
     TargetBitmap bitset(cnt);
     if (bitset.empty()) {
         return bitset;
     }
-    auto hits = wrapper_->match_query(query);
     apply_hits(bitset, hits, true);
     return bitset;
 }

internal/core/unittest/test_text_match.cpp

@@ -139,6 +139,7 @@ TEST(TextMatch, Index) {
     index->Commit();
     index->Reload();
     auto res = index->MatchQuery("football");
+    ASSERT_EQ(res.size(), 3);
     ASSERT_TRUE(res[0]);
     ASSERT_FALSE(res[1]);
     ASSERT_TRUE(res[2]);
@@ -150,6 +151,8 @@ TEST(TextMatch, Index) {
     ASSERT_TRUE(res2[0]);
     ASSERT_FALSE(res2[1]);
     ASSERT_TRUE(res2[2]);
+    res = index->MatchQuery("nothing");
+    ASSERT_EQ(res.size(), 0);
 }
 
 TEST(TextMatch, GrowingNaive) {