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DuckDBArrayResultSet reports wasNull wrong on scalar types (i.e. int, double). #833
Description
DuckDBArrayResultSet uses accessors of DuckDBVector to retrieve values. getInt and others however return a scalar type, i.e. int getInt(int idx) throws SQLException. The assignment to wasNull in org.duckdb.DuckDBArrayResultSet#getValue checking whether value was null will always return false, hence wasNull() will return the wrong result.
I tested 1.5.5.0 only, but expect similar results with older version and on all other scalar types:
Reproducer:
curl -O https://repo1.maven.org/maven2/org/duckdb/duckdb_jdbc/1.5.5.0/duckdb_jdbc-1.5.5.0.jar
cat <<- 'EOF' > Application.java
import java.sql.DriverManager;
import java.sql.SQLException;
void main() throws SQLException {
try (var connection = DriverManager.getConnection("jdbc:duckdb:");
var stmt = connection.createStatement();
var rs = stmt.executeQuery("SELECT [1, null] AS a");
) {
while (rs.next()) {
var a = rs.getArray("a");
var inner = a.getResultSet();
int i = 0;
inner.next();
var val = inner.getInt(2);
assert val == 1;
inner.next();
val = inner.getInt(2);
assert val == 0;
assert inner.wasNull() : "Array result did wrongly reported null state";
}
}
}
EOF
java --enable-native-access=ALL-UNNAMED -ea -cp duckdb_jdbc-1.5.5.0.jar Application.java
rm Application.java
Will yield
Exception in thread "main" java.lang.AssertionError: Array result did wrongly reported null state
at Application.main(Application.java:20)
I use
java -version
openjdk version "26" 2026-03-17
OpenJDK Runtime Environment Zulu26.28+59-CA (build 26+35)
OpenJDK 64-Bit Server VM Zulu26.28+59-CA (build 26+35, mixed mode, sharing)
Reacted by Love Kristofer Leifland
Activity
Fix primitive nullability in ArrayResultSet
Fix primitive nullability in ArrayResultSet (1.5)
staticlibs commentedon Aug 25, 2026
Hi, thanks for the report! I added a fix in #839, snapshot with this fix (compatible with 1.5.5 extensions):
michael-simons commentedon Aug 25, 2026
Very nice, thank you!