Prevent Zero Incriminators

maennchen · Dec 17, 2019 · 320f35a · 320f35a
1 parent 3069b0b
commit 320f35a
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diff --git a/lib/crontab/cron_expression/parser.ex b/lib/crontab/cron_expression/parser.ex
@@ -213,6 +213,10 @@ defmodule Crontab.CronExpression.Parser do
       {_, _, {_clean_divider, remainder}} when remainder != "" ->
         {:error, "Can't parse #{divider} as increment."}
 
+      # Zero increment
+      {_, _, {0, ""}} ->
+        {:error, "Can't parse #{divider} as increment."}
+
       # Found range in <start>-<end> format
       {{:ok, clean_base}, _, {clean_divider, ""}} ->
         {:ok, {:/, clean_base, clean_divider}}

diff --git a/test/crontab/cron_expression/parser_test.exs b/test/crontab/cron_expression/parser_test.exs
@@ -352,4 +352,8 @@ defmodule Crontab.CronExpression.ParserTest do
   test "parse invalid list element gives error" do
     assert parse("* 2,4,invalid * * *") == {:error, "Can't parse invalid as hour."}
   end
+
+  test "parse zero divider gives error" do
+    assert parse("*/0") == {:error, "Can't parse 0 as increment."}
+  end
 end