Improve inVoidContext to take conditional expressions into account.

Max Schaefer · erik-krogh · commit 47e425a184a4 · 2022-05-30T12:37:50.000+02:00
diff --git a/javascript/ql/lib/Expressions/ExprHasNoEffect.qll b/javascript/ql/lib/Expressions/ExprHasNoEffect.qll
@@ -37,6 +37,8 @@ predicate inVoidContext(Expr e) {
   )
   or
   exists(LogicalBinaryExpr logical | e = logical.getRightOperand() and inVoidContext(logical))
+  or
+  exists(ConditionalExpr cond | e = cond.getABranch() | inVoidContext(cond))
 }
 
 /**
diff --git a/javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/ExprHasNoEffect.expected b/javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/ExprHasNoEffect.expected
@@ -10,4 +10,5 @@
 | tst.js:50:3:50:49 | new Syn ... o me?") | This expression has no effect. |
 | tst.js:51:3:51:36 | new Err ... age(e)) | This expression has no effect. |
 | tst.js:62:2:62:20 | o.trivialNonGetter1 | This expression has no effect. |
+| tst.js:78:24:78:24 | o | This expression has no effect. |
 | uselessfn.js:1:1:1:15 | (functi ... .");\\n}) | This expression has no effect. |
diff --git a/javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/tst.js b/javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/tst.js
@@ -73,5 +73,11 @@ function g() {
 	Object.defineProperty(o, "nonTrivialGetter2", unknownGetterDef());
 	o.nonTrivialGetter2; // OK
 	
-	(o: empty); // OK.
+	(o: empty); // OK
+
+	testSomeCondition() ? o : // NOT OK
+		doSomethingDangerous();
+
+	consume(testSomeCondition() ? o : // OK
+		doSomethingDangerous());
 };

Original file line number	Diff line number	Diff line change
`@@ -37,6 +37,8 @@ predicate inVoidContext(Expr e) {`
`37`	`37`	`)`
`38`	`38`	`or`
`39`	`39`	`exists(LogicalBinaryExpr logical \| e = logical.getRightOperand() and inVoidContext(logical))`
	`40`	`+ or`
	`41`	`+ exists(ConditionalExpr cond \| e = cond.getABranch() \| inVoidContext(cond))`
`40`	`42`	`}`
`41`	`43`
`42`	`44`	`/**`