Fixed array to sparsevec cast not limiting to 16,000 non-zero elements [skip ci]

Co-authored-by: 0xJi3F

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.8.6 (unreleased)
+
+- Fixed array to `sparsevec` cast not limiting to 16,000 non-zero elements
+
 ## 0.8.5 (2026-07-08)
 
 - Reduced memory usage for small tables for IVFFlat index builds

src/sparsevec.c

@@ -745,6 +745,7 @@ array_to_sparsevec(PG_FUNCTION_ARGS)
 				 errmsg("unsupported array type")));
 	}
 
+	CheckNnz(nnz, nelemsp);
 	result = InitSparseVector(nelemsp, nnz);
 	values = SPARSEVEC_VALUES(result);
 

test/expected/cast.out

@@ -270,6 +270,8 @@ SELECT array_to_vector(array_agg(n), 16001, false) FROM generate_series(1, 16001
 ERROR:  vector cannot have more than 16000 dimensions
 SELECT array_agg(n)::halfvec FROM generate_series(1, 16001) n;
 ERROR:  halfvec cannot have more than 16000 dimensions
+SELECT array_agg(n)::sparsevec FROM generate_series(1, 16001) n;
+ERROR:  sparsevec cannot have more than 16000 non-zero elements
 -- ensure no error
 SELECT ARRAY[1,2,3] = ARRAY[1,2,3];
  ?column? 

test/sql/cast.sql

@@ -77,6 +77,7 @@ SELECT '{{1}}'::real[]::sparsevec;
 SELECT array_agg(n)::vector FROM generate_series(1, 16001) n;
 SELECT array_to_vector(array_agg(n), 16001, false) FROM generate_series(1, 16001) n;
 SELECT array_agg(n)::halfvec FROM generate_series(1, 16001) n;
+SELECT array_agg(n)::sparsevec FROM generate_series(1, 16001) n;
 
 -- ensure no error
 SELECT ARRAY[1,2,3] = ARRAY[1,2,3];