False Negative: ContinueInFalseLoop.ql misses `do ... while(false)` loops once `false` is stored in a local.

從 Likely Bugs/Statements/ContinueInFalseLoop.ql 開始，檢查它在 false 儲存於區域變數中時如何評估 do-loop 條件。查看受影響的 PosCase1_Var1.java 和 PosCase1_Var5.java 案例，然後執行 checker 測試，以確認兩個案例都會被標記，同時現有的字面值 false 行為仍然得到涵蓋。

False Negative: ContinueInFalseLoop.ql misses do ... while(false) loops once false is stored in a local.

Version
codeql 2.24.3

Checker

• Checker id: Likely Bugs/Statements/ContinueInFalseLoop.ql
• Checker description: This checker detects a 'continue' statement inside a 'do' loop whose condition is always false, meaning the continue will never actually re-run the loop body.

Description of the false negative

Both samples are still do loops whose condition is false and therefore cannot loop back after continue. The only difference is that the literal false is first assigned to a local variable.

That should still be a direct hit for Likely Bugs/Statements/ContinueInFalseLoop.ql.

Affected test cases

PosCase1_Var1.java

never is a constant false value, so the continue still cannot re-enter the loop body.

// A do loop with a literal false condition contains a continue statement targeting that same loop should be flagged as a positive case.
package scensct.var.pos;

public class PosCase1_Var1 {
    public static void main(String[] args) {
        final boolean never = false;
        do {
            // continue inside do with false condition
            continue;
        } while (never);
    }
}

PosCase1_Var5.java

flag is initialized from Boolean.FALSE and never changed. This is still the same impossible loop-back case.

// A do loop with a literal false condition contains a continue statement targeting that same loop should be flagged as a positive case.
package scensct.var.pos;

public class PosCase1_Var5 {
    public static void main(String[] args) {
        boolean flag = Boolean.FALSE;
        do {
            // continue inside do with false condition
            continue;
        } while (flag);
    }
}

Cause analysis

The miss is surprisingly basic. The query appears to require a literal false at the loop condition and loses the result as soon as that same value is stored in a local.

For developers, these are the same bug. Whether the condition is written as while (false) or while (never) should not matter.

References

None known.