From d5106c723303a1f59898aa7335332f18afe2a29c Mon Sep 17 00:00:00 2001
From: Matej Ferencevic <matej.ferencevic@memgraph.io>
Date: Tue, 16 Jul 2019 10:35:23 +0200
Subject: [PATCH] Handle zero increment in counters

Reviewers: teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2208
---
 src/query/interpret/awesome_memgraph_functions.cpp | 7 ++++++-
 tests/unit/query_expression_evaluator.cpp          | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/query/interpret/awesome_memgraph_functions.cpp b/src/query/interpret/awesome_memgraph_functions.cpp
index 9b615f8ae..f11a17099 100644
--- a/src/query/interpret/awesome_memgraph_functions.cpp
+++ b/src/query/interpret/awesome_memgraph_functions.cpp
@@ -702,7 +702,12 @@ TypedValue Counter(TypedValue *args, int64_t nargs,
         "Third argument of 'counter' must be an integer.");
 
   int64_t step = 1;
-  if (nargs == 3) step = args[2].ValueInt();
+  if (nargs == 3) {
+    step = args[2].ValueInt();
+    if (step == 0)
+      throw QueryRuntimeException(
+          "Third argument of 'counter' must not be zero.");
+  }
 
   auto [it, inserted] =
       context.counters.emplace(args[0].ValueString(), args[1].ValueInt());
diff --git a/tests/unit/query_expression_evaluator.cpp b/tests/unit/query_expression_evaluator.cpp
index 55524c49d..2ae5054ca 100644
--- a/tests/unit/query_expression_evaluator.cpp
+++ b/tests/unit/query_expression_evaluator.cpp
@@ -1494,6 +1494,8 @@ TEST_F(FunctionTest, Counter) {
   EXPECT_EQ(EvaluateFunction("COUNTER", "c5", 0, -5).ValueInt(), 0);
   EXPECT_EQ(EvaluateFunction("COUNTER", "c5", 0, -5).ValueInt(), -5);
   EXPECT_EQ(EvaluateFunction("COUNTER", "c5", 0, -5).ValueInt(), -10);
+
+  EXPECT_THROW(EvaluateFunction("COUNTER", "c6", 0, 0), QueryRuntimeException);
 }
 
 TEST_F(FunctionTest, Id) {