accept K parameter as float if there is no loss in the precision after rounding to the integer

- it cah be hard in some cliens (JS for example) to distinguish between INTEGERs and FLOATs - so we always bind FLOATs instead
- this create unnecessary error: "vector index(search): third parameter (k) must be a non-negative integer"

Author: sivukhin

libsql-sqlite3/src/vectorIndex.c

@@ -951,6 +951,7 @@ int vectorIndexSearch(
   char **pzErrMsg
 ) {
   int type, dims, k, rc;
+  double kDouble;
   const char *zIdxName;
   const char *zErrMsg;
   Vector *pVector = NULL;
@@ -981,17 +982,32 @@ int vectorIndexSearch(
     rc = SQLITE_ERROR;
     goto out;
   }
-  if( sqlite3_value_type(argv[2]) != SQLITE_INTEGER ){
-    *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be a non-negative integer");
-    rc = SQLITE_ERROR;
-    goto out;
-  }
-  k = sqlite3_value_int(argv[2]);
-  if( k < 0 ){
-    *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be a non-negative integer");
+  if( sqlite3_value_type(argv[2]) == SQLITE_INTEGER ){
+    k = sqlite3_value_int(argv[2]);
+    if( k < 0 ){
+      *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be a non-negative integer, but negative value were provided");
+      rc = SQLITE_ERROR;
+      goto out;
+    }
+  }else if( sqlite3_value_type(argv[2]) == SQLITE_FLOAT ) {
+    kDouble = sqlite3_value_double(argv[2]);
+    k = (int)kDouble;
+    if( (double)k != kDouble ){
+      *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be an integer, but float value were provided");
+      rc = SQLITE_ERROR;
+      goto out;
+    }
+    if( k < 0 ){
+      *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be a non-negative integer, but negative value were provided");
+      rc = SQLITE_ERROR;
+      goto out;
+    }
+  }else{
+    *pzErrMsg = sqlite3_mprintf("vector index(search): third parameter (k) must be an integer, but unexpected type of value were provided");
     rc = SQLITE_ERROR;
     goto out;
   }
+
   if( sqlite3_value_type(argv[0]) != SQLITE_TEXT ){
     *pzErrMsg = sqlite3_mprintf("vector index(search): first parameter (index) must be a string");
     rc = SQLITE_ERROR;

libsql-sqlite3/test/libsql_vector_index.test

@@ -117,7 +117,8 @@ do_execsql_test vector-simple {
   SELECT * FROM vector_top_k('t_simple_idx', '[1,2,3]', 1);
   SELECT * FROM vector_top_k('t_simple_idx', '[5,6,7]', 1);
   SELECT * FROM vector_top_k('t_simple_idx', vector('[1,2,3]'), 1);
-} {{1} {3} {1}}
+  SELECT * FROM vector_top_k('t_simple_idx', vector('[1,2,3]'), CAST(1 as REAL));
+} {{1} {3} {1} {1}}
 
 do_execsql_test vector-empty {
   CREATE TABLE t_empty( v FLOAT32(3));
@@ -484,6 +485,7 @@ do_test vector-errors {
   lappend ret [error_messages {INSERT INTO t_err3 VALUES (vector('[1, 2, 3, 4, 5]'))}]
   lappend ret [error_messages {INSERT INTO t_err3 VALUES (vector64('[1,2,3,4]'))}]
   lappend ret [error_messages {SELECT * FROM vector_top_k('t_err3_idx', vector('[1,2]'), 2)}]
+  lappend ret [error_messages {SELECT * FROM vector_top_k('t_err3_idx', vector('[1,2,3,4]'), 2.5)}]
   sqlite3_exec db { CREATE TABLE t_mixed_t( v FLOAT32(3)); }
   sqlite3_exec db { INSERT INTO t_mixed_t VALUES('[1]'); }
   lappend ret [error_messages {CREATE INDEX t_mixed_t_idx ON t_mixed_t( libsql_vector_idx(v) )}]
@@ -503,5 +505,6 @@ do_test vector-errors {
   {vector index(insert): dimensions are different: 5 != 4}
   {vector index(insert): vector type differs from column type: 2 != 1}
   {vector index(search): dimensions are different: 2 != 4}
+  {vector index(search): third parameter (k) must be an integer, but float value were provided}
   {vector index(insert): dimensions are different: 1 != 3}
 }]