Ruby: revome cases where the loop may be interrupted

Author: yoff

ruby/ql/src/queries/performance/CouldBeAsync.ql

@@ -9,8 +9,10 @@
  */
 
 import ruby
+private import codeql.ruby.AST
 import codeql.ruby.Concepts
 import codeql.ruby.frameworks.ActiveRecord
+private import codeql.ruby.TaintTracking
 
 string loopMethodName() {
   result in [
@@ -33,7 +35,6 @@ predicate happensInLoop(LoopingCall loop, DataFlow::CallNode e) {
   loop.getLoopBlock().asCallableAstNode() = e.asExpr().getScope()
 }
 
-// predicate directLoop(@ruby_while)
 predicate happensInOuterLoop(LoopingCall outerLoop, DataFlow::CallNode e) {
   exists(LoopingCall innerLoop |
     happensInLoop(outerLoop, innerLoop) and
@@ -58,10 +59,28 @@ private ActiveRecordInstance getChain(ActiveRecordInstanceMethodCall c) {
   result = getChain(c.getInstance())
 }
 
+// The ActiveRecord instance is used to potentially control the loop
+predicate usedInLoopControlGuard(ActiveRecordInstance ar, DataFlow::Node guard) {
+  TaintTracking::localTaint(ar, guard) and
+  guard = guardForLoopControl(_, _)
+}
+
+// A guard for controlling the loop
+DataFlow::Node guardForLoopControl(ConditionalExpr cond, Stmt control) {
+  result.asExpr().getAstNode() = cond.getCondition().getAChild*() and
+  (
+    control.(MethodCall).getMethodName() = "raise"
+    or
+    control instanceof NextStmt
+  ) and
+  control = cond.getBranch(_).getAChild()
+}
+
 from LoopingCall loop, DataFlow::CallNode call, string message
 where
   not call.getLocation().getFile().getAbsolutePath().matches("%test%") and
   not call = any(PluckCall p).chaines() and
+  not usedInLoopControlGuard(call, _) and
   happensInInnermostLoop(loop, call) and
   (
     call instanceof ActiveRecordModelFinderCall and