github / github/codeql

False Positive: CloseSql.ql reports a ResultSet that is already scoped by try-with-resources on its parent Statement.

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Description

Version
codeql 2.24.3

## Checker
- Checker id: `Likely Bugs/Resource Leaks/CloseSql.ql`
- Checker description: This checker detects SQL resource objects (Connection, Statement, ResultSet) that are initialized locally and not guaranteed to be closed on method exit.

## Description of the false positive
This case should stay out of the result set. The `ResultSet` is created from a `Statement` that is itself managed by try-with-resources, together with the owning `Connection`. Once the `try` block exits, both parent resources are closed, and the `ResultSet` lifetime is covered by that ownership chain.

The alias on the `Statement` does not change that. It is still the same tracked resource.

## Affected test cases
### `NegCase7_Var3.java`
`stmtAlias` is just another reference to `originalStmt`. The query appears to lose that alias relationship and treats `rs` as if it were detached from the try-with-resources scope.

```java
// A locally initialized SQL ResultSet obtained via a method call on a Statement variable, where Statement is a transitive parent closeable resource, should not be flagged as unclosed.
package scensct.var.neg;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;

public class NegCase7_Var3 {
public void test() throws Exception {
try (Connection conn = DriverManager.getConnection("jdbc:test");
Statement originalStmt = conn.createStatement()) {
// Alias the Statement
Statement stmtAlias = originalStmt;
// Always-true condition
if (conn != null) {
// Locally initialized ResultSet via method call on aliased Statement
ResultSet rs = stmtAlias.executeQuery("SELECT 1"); // [REPORTED LINE]
}
}
}
}
```

## Cause analysis
`Likely Bugs/Resource Leaks/CloseSql.ql` is supposed to report SQL resources that are not guaranteed to be closed. That is not what this sample is doing.

The only reason this gets reported is that the `Statement` is referenced through `stmtAlias` instead of its original local name. If the query stops recognizing parent-resource ownership after a trivial alias, it will produce noise in ordinary JDBC code where objects are routinely passed through locals before use.

This is an ownership-tracking false positive, not a real leak.

Contributor guide

Open the contributing guide

Research direction

Start by reading Likely Bugs/Resource Leaks/CloseSql.ql and the NegCase7_Var3.java example. Reproduce the report for the aliased Statement and inspect how parent-resource ownership is tracked. Done means the ResultSet in this case is no longer reported while genuine unclosed SQL resources remain covered.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
security
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
68/100

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