From 11e5c372862ec00e57460b37ccfee51c6d93c5f7 Mon Sep 17 00:00:00 2001
From: Josh Rosen <joshrosen@databricks.com>
Date: Tue, 14 Jul 2015 16:08:17 -0700
Subject: [SPARK-8962] Add Scalastyle rule to ban direct use of Class.forName;
 fix existing uses

This pull request adds a Scalastyle regex rule which fails the style check if `Class.forName` is used directly.  `Class.forName` always loads classes from the default / system classloader, but in a majority of cases, we should be using Spark's own `Utils.classForName` instead, which tries to load classes from the current thread's context classloader and falls back to the classloader which loaded Spark when the context classloader is not defined.

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Author: Josh Rosen <joshrosen@databricks.com>

Closes #7350 from JoshRosen/ban-Class.forName and squashes the following commits:

e3e96f7 [Josh Rosen] Merge remote-tracking branch 'origin/master' into ban-Class.forName
c0b7885 [Josh Rosen] Hopefully fix the last two cases
d707ba7 [Josh Rosen] Fix uses of Class.forName that I missed in my first cleanup pass
046470d [Josh Rosen] Merge remote-tracking branch 'origin/master' into ban-Class.forName
62882ee [Josh Rosen] Fix uses of Class.forName or add exclusion.
d9abade [Josh Rosen] Add stylechecker rule to ban uses of Class.forName
---
 scalastyle-config.xml | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'scalastyle-config.xml')

diff --git a/scalastyle-config.xml b/scalastyle-config.xml
index 4961170379..b5e2e882d2 100644
--- a/scalastyle-config.xml
+++ b/scalastyle-config.xml
@@ -150,6 +150,17 @@ This file is divided into 3 sections:
       // scalastyle:on println]]></customMessage>
   </check>
 
+  <check customId="classforname" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
+    <parameters><parameter name="regex">Class\.forName</parameter></parameters>
+    <customMessage><![CDATA[
+      Are you sure that you want to use Class.forName? In most cases, you should use Utils.classForName instead.
+      If you must use Class.forName, wrap the code block with
+      // scalastyle:off classforname
+      Class.forName(...)
+      // scalastyle:on classforname
+    ]]></customMessage>
+  </check>
+
   <!-- ================================================================================ -->
   <!--       rules we'd like to enforce, but haven't cleaned up the codebase yet        -->
   <!-- ================================================================================ -->
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