codeql/java/ql/test/query-tests/Nullness/B.java at codeql-cli/v2.27.1 · github/codeql · GitHub

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public class B {

private boolean maybe;

public final boolean flag;

public B(boolean b, boolean f) {

this.maybe = b;

this.flag = f;

}

public void caller() {

callee1(new Object());

callee1(null);

callee2(new Object());

}

public void callee1(Object param) {

param.toString(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

public void callee2(Object param) {

if (param != null) {

param.toString(); // OK

}

param.toString(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

private static boolean customIsNull(Object x) {

if (x instanceof String) return false;

if (x == null) return true;

return x == null;

}

public void nullGuards() {

Object o1 = maybe ? null : new Object();

if (o1 != null) o1.hashCode(); // OK

Object o2 = maybe ? null : "";

if (o2 instanceof String) o2.hashCode(); // OK

Object o3 = null;

if ((o3 = maybe ? null : "") != null) o3.hashCode(); // OK

Object o4 = maybe ? null : "";

if ((2 > 1 && o4 != null) != false) o4.hashCode(); // OK

Object o5 = (o4 != null) ? "" : null;

if (o5 != null) o4.hashCode(); // OK

if (o4 != null) o5.hashCode(); // OK

Object o6 = maybe ? null : "";

if (!customIsNull(o6)) o6.hashCode(); // OK

Object o7 = maybe ? null : "";

boolean ok = o7 != null && 2 > 1;

if (ok)

o7.hashCode(); // OK

else

o7.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

Object o8 = maybe ? null : "";

int track = o8 == null ? 42 : 1+1;

if (track == 2) o8.hashCode(); // OK

if (track != 42) o8.hashCode(); // OK

if (track < 42) o8.hashCode(); // OK

if (track <= 41) o8.hashCode(); // OK

}

public void deref() {

int[] xs = maybe ? null : new int[2];

if (2 > 1) xs[0] = 5; // $ Alert[java/dereferenced-value-may-be-null] // NPE

if (2 > 1) maybe = xs[1] > 5; // $ Alert[java/dereferenced-value-may-be-null] // NPE

if (2 > 1) {

int l = xs.length; // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

if (2 > 1) {

for (int i : xs) { } // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

if (2 > 1) {

synchronized(xs) { // $ Alert[java/dereferenced-value-may-be-null] // NPE

xs.hashCode(); // Not reported - same basic block

}

if (4 > 3) {

assert xs != null;

xs[0] = xs[1]; // OK

}

public void f(boolean b) {

String x = b ? null : "abc";

x = x == null ? "" : x;

if (x == null)

x.hashCode(); // OK - dead

else

x.hashCode(); // OK

}

public void lengthGuard(int[] a, int[] b) {

int alen = a == null ? 0 : a.length; // OK

int blen = b == null ? 0 : b.length; // OK

int sum = 0;

if (alen == blen) {

for(int i = 0; i < alen; i++) {

sum += a[i]; // OK

sum += b[i]; // OK

}

int alen2;

if (a != null)

alen2 = a.length; // OK

else

alen2 = 0;

for(int i = 1; i <= alen2; ++i) {

sum += a[i-1]; // OK

}

public void missedGuard(Object obj) {

obj.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

int x = obj != null ? 1 : 0;

}

private Object mkMaybe() {

if (maybe) throw new RuntimeException();

return new Object();

}

public void exceptions() {

Object obj = null;

try {

obj = mkMaybe();

} catch(Exception e) {

}

obj.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

Object obj2 = null;

try {

obj2 = mkMaybe();

} catch(Exception e) {

assert false;

}

obj2.hashCode(); // OK

Object obj3 = null;

try {

obj3 = mkMaybe();

} finally {

//cleanup

}

obj3.hashCode(); // OK

}

public void clearNotNull() {

Object o = new Object();

if (o == null) o.hashCode(); // OK

o.hashCode(); // OK

try {

mkMaybe();

} catch(Exception e) {

if (e == null) e.hashCode(); // OK

e.hashCode(); // OK

}

Object n = null;

Object o2 = n == null ? new Object() : n;

o2.hashCode(); // OK

Object o3 = "abc";

if (o3 == null) o3.hashCode(); // OK

o3.hashCode(); // OK

Object o4 = "" + null;

if (o4 == null) o4.hashCode(); // OK

o4.hashCode(); // OK

}

public void correlatedConditions(boolean cond, int num) {

Object o = null;

if (cond) o = new Object();

if (cond) o.hashCode(); // OK

o = null;

if (flag) o = "";

if (flag) o.hashCode(); // OK

o = null;

Object other = maybe ? null : "";

if (other == null) o = "";

if (other != null)

o.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

else

o.hashCode(); // OK

Object o2 = (num < 0) ? null : "";

if (num < 0)

o2 = "";

else

o2.hashCode(); // OK

}

public void trackingVariable(int[] a) {

Object o = null;

Object other = null;

if (maybe) {

o = "abc";

other = "def";

}

if (other instanceof String) o.hashCode(); // OK

o = null;

int count = 0;

boolean found = false;

for (int i = 0; i < a.length; i++) {

if (a[i] == 42) {

o = ((Integer)a[i]).toString();

count++;

if (2 > 1) { }

found = true;

}

if (a[i] > 10000) {

o = null;

count = 0;

if (2 > 1) { }

found = false;

}

if (count > 3) o.hashCode(); // OK

if (found) o.hashCode(); // OK

Object prev = null;

for (int i = 0; i < a.length; ++i) {

if (i != 0) prev.hashCode(); // OK

prev = a[i];

}

String s = null;

if (2 > 1) {

boolean s_null = true;

for (int i : a) {

s_null = false;

s = "" + a;

}

if (!s_null) s.hashCode(); // OK

}

Object r = null;

MyStatus stat = MyStatus.INIT;

while (stat == MyStatus.INIT && stat != MyStatus.READY) {

r = mkMaybe();

if (2 > 1)

stat = MyStatus.READY;

}

r.hashCode(); // OK

}

public enum MyStatus {

READY,

INIT

}

public void g(Object obj) {

String msg = null;

if(obj == null)

msg = "foo";

else if(obj.hashCode() > 7) { // OK

msg = "bar";

}

if(msg != null) {

msg += "foobar";

throw new RuntimeException(msg);

}

obj.hashCode(); // OK

}

public void loopCorr(int iters) {

int[] a = null;

if (iters > 0) a = new int[iters];

for (int i = 0; i < iters; ++i)

a[i] = 0; // OK

if (iters > 0) {

String last = null;

for (int i = 0; i < iters; i++) last = "abc";

last.hashCode(); // OK

}

int[] b = maybe ? null : new int[iters];

if (iters > 0 && (b == null || b.length < iters)) {

throw new RuntimeException();

}

for (int i = 0; i < iters; ++i) {

b[i] = 0; // OK

}

void test(Exception e, boolean b) {

Exception ioe = null;

if (b) {

ioe = new Exception("");

}

if (ioe != null) {

ioe = e;

} else {

ioe.getMessage(); // $ Alert[java/dereferenced-value-is-always-null] // NPE; always

}

public void lengthGuard2(int[] a, int[] b) {

int alen = a == null ? 0 : a.length; // OK

int sum = 0;

int i;

for(i = 0; i < alen; i++) {

sum += a[i]; // OK

}

int blen = b == null ? 0 : b.length; // OK

for(i = 0; i < blen; i++) {

sum += b[i]; // OK

}

i = -3;

}

public void corrConds2(Object x, Object y) {

if ((x != null && y == null) || (x == null && y != null)) return;

if (x != null) y.hashCode(); // OK

if (y != null) x.hashCode(); // OK

}

public void corrConds3(Object y) {

Object x = null;

if(y instanceof String) {

x = new Object();

}

if(y instanceof String) {

x.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

public void corrConds4(Object y) {

Object x = null;

if(!(y instanceof String)) {

x = new Object();

}

if(!(y instanceof String)) {

x.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

public void corrConds5(Object y, Object z) {

Object x = null;

if(y == z) {

x = new Object();

}

if(y == z) {

x.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

Object x2 = null;

if(y != z) {

x2 = new Object();

}

if(y != z) {

x2.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

Object x3 = null;

if(y != z) {

x3 = new Object();

}

if(!(y == z)) {

x3.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

public void bitwise(Object x, boolean b) {

boolean notnull = x != null;

boolean g1 = notnull;

g1 &= b;

if (g1) {

x.hashCode(); // OK

}

boolean g2 = b;

g2 &= notnull;

if (g2) {

x.hashCode(); // OK

}

boolean g3 = !notnull;

g3 |= b;

if (!g3) {

x.hashCode(); // OK

}

boolean g4 = b;

g4 |= !notnull;

if (!g4) {

x.hashCode(); // OK

}

boolean g5 = g1 = b & notnull;

if (g5) {

x.hashCode(); // OK

}

g5 |= b;

if (g5) {

x.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

public void corrCondLoop1(boolean a[]) {

Object x = new Object();

for (int i = 0; i < a.length; i++) {

boolean b = a[i];

if (b) {

x = null;

}

if (!b) {

x.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

// flow can loop around from one iteration to the next

}

public void corrCondLoop2(boolean a[]) {

for (int i = 0; i < a.length; i++) {

// x is local to the loop iteration and thus cannot loop around and reach the sink

Object x = new Object();

boolean b = a[i];

if (b) {

x = null;

}

if (!b) {

x.hashCode(); // OK

}

public void loopCorrTest1(int[] a) {

boolean ready = a.length > 7;

Object x = new Object();

for (int i = 0; i < a.length; i++) {

// condition correlates with itself through iterations when ready isn't updated

if (!ready) {

x = null;

} else {

x.hashCode(); // OK

}

if ((a[i] & 1) != 0) {

ready = (a[i] & 2) != 0;

x = new Object();

}

public void loopCorrTest2(boolean[] a) {

Object x = new Object();

boolean cur = a[0];

for (int i = 1; i < a.length; i++) {

boolean prev = cur;

cur = a[i];

if (!prev) {

// correctly guarded by !cur from the _previous_ iteration

x.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

} else {

x = new Object();

}

if (cur) {

x = null;

}

public void loopCorrTest3(String[] ss) {

Object x = null;

Object t = null;

for (String s : ss) {

if (t == null) {

t = s;

} else {

if (t instanceof String) {

x = new Object();

t = new Object();

}

// correctly guarded by t: null -> String -> Object

x.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

}

public void initCorr(boolean b) {

Object o2 = b ? null : "";

if (b)

o2 = "";

else

o2.hashCode(); // OK

}

public void complexLoopTest(int[] xs, int[] ys) {

int len = ys != null ? ys.length : 0;

for (int i = 0, j = 0; i < xs.length; i++) {

if (j < len && ys[j] == 42) { // OK

j++;

} else if (j > 0) {

ys[0]++; // OK

}

public void trackTest(Object o, int n) {

boolean isnull = o == null;

int c = -1;

if (maybe) { }

if (c == 100) { return; }

o.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

public void testFinally(int[] xs, int[] ys) {

if (xs.length == 0) return;

if (ys.length == 0) return;

String s1 = null;

String s2 = null;

for (int x : xs) {

try {

if (x == 0) { break; }

s1 = "1";

for (int y : ys) {

if (y == 0) { break; }

s2 = "2";

}

} finally {

}

s1.hashCode(); // OK

s2.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

s1.hashCode(); // $ Alert[java/dereferenced-value-may-be-null] // NPE

}

public void lenCheck(int[] xs, int n, int t) {

if (n > 42) return;

if (maybe) {}

if (n > 0 && (xs == null || xs.length < n)) {

return;

}

if (maybe) {}

if (n > 21) return;

if (maybe) {}

for (int i = 0; i < n; ++i) {

xs[i]++; // OK

}

public void rangetest(int n) {

String s = null;

if (n < 0 || n > 10) s = "A";

if (n > 100) s.hashCode(); // OK

if (n == 42) s.hashCode(); // OK

}

public void testFinally2(int[] xs) {

String s = null;

int i = 0;

while (true) {

try {

int x = xs[i++];

if (x == 0) {

s = "foo";

break;

} else if (x == 1) {

continue;

}

} finally {

}

s.hashCode(); // $ SPURIOUS: Alert[java/dereferenced-value-may-be-null] // Spurious NPE - false positive

// CFG reachability does not distinguish abrupt successors

}

codeql/java/ql/test/query-tests/Nullness/B.java at codeql-cli/v2.27.1 · github/codeql · GitHub

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