From 9e1d96c1f265610ba9fa4f729b5aa66079d113f5 Mon Sep 17 00:00:00 2001
From: Kyriakos Nikolaos Gkorogiannis <nikosgorogiannis@fb.com>
Date: Fri, 6 Oct 2017 07:27:32 -0700
Subject: [PATCH] [threadsafety] Fix exception thrown by list of actuals and
 formals not having the same length in some cases (C++?)

Reviewed By: jberdine

Differential Revision: D5995583

fbshipit-source-id: 2d3debf
---
 infer/src/checkers/ThreadSafety.ml            |  2 +-
 .../cpp/threadsafety/variadic.cpp             | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 infer/tests/codetoanalyze/cpp/threadsafety/variadic.cpp

diff --git a/infer/src/checkers/ThreadSafety.ml b/infer/src/checkers/ThreadSafety.ml
index 74194500c..0f27f0fab 100644
--- a/infer/src/checkers/ThreadSafety.ml
+++ b/infer/src/checkers/ThreadSafety.ml
@@ -581,7 +581,7 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
     let open Domain in
     let formals, _ = FormalMap.make pdesc |> FormalMap.get_formals_indexes |> List.unzip in
     let fmls_actls =
-      List.zip_exn formals actuals
+      List.zip_exn formals (List.take actuals (List.length formals))
       |> List.filter_map ~f:(fun (fml, act) ->
              match get_access_path act with Some path -> Some (fml, path) | _ -> None )
     in
diff --git a/infer/tests/codetoanalyze/cpp/threadsafety/variadic.cpp b/infer/tests/codetoanalyze/cpp/threadsafety/variadic.cpp
new file mode 100644
index 000000000..e2220f0cf
--- /dev/null
+++ b/infer/tests/codetoanalyze/cpp/threadsafety/variadic.cpp
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include <cstdarg>
+#include <cstdio>
+
+double average(int count, ...) {
+  va_list ap;
+  int j;
+  double sum = 0;
+
+  va_start(ap,
+           count); /* Requires the last fixed parameter (to get the address) */
+  for (j = 0; j < count; j++) {
+    sum += va_arg(ap, int); /* Increments ap to the next argument. */
+  }
+  va_end(ap);
+
+  return sum / count;
+}
+
+int main(int argc, char const* argv[]) {
+  printf("%f\n", average(3, 1, 2, 3));
+  return 0;
+}