hohn/codeql
1
0
Fork 0
mirror of https://github.com/github/codeql.git synced 2026-04-30 19:26:02 +02:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #404 from asger-semmle/useless-conditional2

Browse Source 
Approved by xiemaisi
This commit is contained in:
semmle-qlci
2018-11-07 08:28:01 +00:00
committed by GitHub
parent 212a78b5fc 87e0027974
commit 282d1e2096
3 changed files with 25 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
javascript/ql/src/Statements/UselessConditional.ql
View File

@@ -120,9 +120,11 @@ predicate whitelist(Expr e) {
*/
predicate isConditional(ASTNode cond, Expr e) {
e = cond.(IfStmt).getCondition() or
e = cond.(LoopStmt).getTest() or
e = cond.(ConditionalExpr).getCondition() or
e = cond.(LogAndExpr).getLeftOperand() or
e = cond.(LogOrExpr).getLeftOperand()
e = cond.(LogicalBinaryExpr).getLeftOperand() or
// Include `z` in `if (x && z)`.
isConditional(_, cond) and e = cond.(Expr).getUnderlyingValue().(LogicalBinaryExpr).getRightOperand()
}
from ASTNode cond, DataFlow::AnalyzedNode op, boolean cv, ASTNode sel, string msg
@@ -132,7 +134,7 @@ where isConditional(cond, op.asExpr()) and
// if `cond` is of the form `<non-trivial truthy expr> && <something>`,
// we suggest replacing it with `<non-trivial truthy expr>, <something>`
if cond instanceof LogAndExpr and cv = true and not op.asExpr().isPure() then
if cond.(LogAndExpr).getLeftOperand() = op.asExpr() and cv = true and not op.asExpr().isPure() then
(sel = cond and msg = "This logical 'and' expression can be replaced with a comma expression.")
// otherwise we just report that `op` always evaluates to `cv`

5
javascript/ql/test/query-tests/Statements/UselessConditional/UselessConditional.expected
View File

@@ -16,6 +16,11 @@
| UselessConditional.js:76:13:76:13 | x | This use of variable 'x' always evaluates to true. |
| UselessConditional.js:82:13:82:13 | x | This use of variable 'x' always evaluates to true. |
| UselessConditional.js:89:10:89:16 | x, true | This expression always evaluates to true. |
| UselessConditional.js:94:16:94:16 | x | This use of variable 'x' always evaluates to false. |
| UselessConditional.js:100:13:100:24 | true && true | This expression always evaluates to true. |
| UselessConditional.js:101:18:101:18 | x | This use of variable 'x' always evaluates to false. |
| UselessConditional.js:102:19:102:19 | x | This use of variable 'x' always evaluates to false. |
| UselessConditional.js:103:23:103:23 | x | This use of variable 'x' always evaluates to false. |
| UselessConditionalGood.js:58:12:58:13 | x2 | This use of variable 'x2' always evaluates to false. |
| UselessConditionalGood.js:69:12:69:13 | xy | This use of variable 'xy' always evaluates to false. |
| UselessConditionalGood.js:85:12:85:13 | xy | This use of variable 'xy' always evaluates to false. |

15
javascript/ql/test/query-tests/Statements/UselessConditional/UselessConditional.js
View File

@@ -89,4 +89,19 @@ async function awaitFlow(){
if ((x, true));
});
(function (x, y) {
if (!x) {
while (x) { // NOT OK
f();
}
while (true) { // OK
break;
}
if (true && true) {} // NOT OK
if (y && x) {} // NOT OK
if (y && (x)) {} // NOT OK
do { } while (x); // NOT OK
}
});
// semmle-extractor-options: --experimental