scalastyle-config.xml

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<!--
  ~ This file contains code from the Apache Spark project (original license above).
  ~It contains modifications, which are licensed as follows:
  -->

<!--
  ~ Copyright 2021 IBM Corp.
  ~ SPDX-License-Identifier: Apache-2.0
  -->
<!--

If you wish to turn off checking for a section of code, you can put a comment in the source
before and after the section, with the following syntax:

  // scalastyle:off
  ...  // stuff that breaks the styles
  // scalastyle:on

You can also disable only one rule, by specifying its rule id, as specified in:
  http://www.scalastyle.org/rules-0.7.0.html

  // scalastyle:off no.finalize
  override def finalize(): Unit = ...
  // scalastyle:on no.finalize

This file is divided into 3 sections:
 (1) rules that we enforce.
 (2) rules that we would like to enforce, but haven't cleaned up the codebase to turn on yet
     (or we need to make the scalastyle rule more configurable).
 (3) rules that we don't want to enforce.
-->

<scalastyle>
 <name>Scalastyle standard configuration</name>

 <!-- ================================================================================ -->
 <!--                               rules we enforce                                   -->
 <!-- ================================================================================ -->

 <check level="error" class="org.scalastyle.file.FileTabChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.file.HeaderMatchesChecker" enabled="true">
  <parameters>
   <parameter name="regex">true</parameter>
   <parameter name="header"><![CDATA[(?:\Q/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * This file contains code from the spark project (original license above).
 * It contains modifications, which are licensed as follows:
 */

\E)?\Q/*
 * Copyright 2021 IBM Corp.
 * SPDX-License-Identifier: Apache-2.0
 */\E]]></parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.SpacesAfterPlusChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.SpacesBeforePlusChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.file.WhitespaceEndOfLineChecker" enabled="true"></check>


 <check level="error" class="org.scalastyle.file.FileLineLengthChecker" enabled="true">
  <parameters>
   <parameter name="maxLineLength"><![CDATA[100]]></parameter>
   <parameter name="tabSize"><![CDATA[2]]></parameter>
   <parameter name="ignoreImports">true</parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.ClassNamesChecker" enabled="true">
  <parameters><parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter></parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.ObjectNamesChecker" enabled="true">
  <parameters><parameter name="regex"><![CDATA[(config|[A-Z][A-Za-z]*)]]></parameter></parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.PackageObjectNamesChecker" enabled="true">
  <parameters><parameter name="regex"><![CDATA[^[a-z][A-Za-z]*$]]></parameter></parameters>
 </check>

 <check customId="argcount" level="error" class="org.scalastyle.scalariform.ParameterNumberChecker" enabled="true">
  <parameters><parameter name="maxParameters"><![CDATA[10]]></parameter></parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.NoFinalizeChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.CovariantEqualsChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.StructuralTypeChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.UppercaseLChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.IfBraceChecker" enabled="true">
  <parameters>
   <parameter name="singleLineAllowed"><![CDATA[true]]></parameter>
   <parameter name="doubleLineAllowed"><![CDATA[true]]></parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.PublicMethodsHaveTypeChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.file.NewLineAtEofChecker" enabled="true"></check>

 <check customId="nonascii" level="error" class="org.scalastyle.scalariform.NonASCIICharacterChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.SpaceAfterCommentStartChecker" enabled="true"></check>

 <!-- ??? usually shouldn't be checked into the code base. -->
 <check level="error" class="org.scalastyle.scalariform.NotImplementedErrorUsage" enabled="true"></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>

 <check customId="caselocale" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
  <parameters><parameter name="regex">(\.toUpperCase|\.toLowerCase)(?!(\(|\(Locale.ROOT\)))</parameter></parameters>
  <customMessage><![CDATA[
      Are you sure that you want to use toUpperCase or toLowerCase without the root locale? In most cases, you
      should use toUpperCase(Locale.ROOT) or toLowerCase(Locale.ROOT) instead.
      If you must use toUpperCase or toLowerCase without the root locale, wrap the code block with
      // scalastyle:off caselocale
      .toUpperCase
      .toLowerCase
      // scalastyle:on caselocale
    ]]></customMessage>
 </check>

 <check customId="throwerror" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
  <parameters><parameter name="regex">throw new \w+Error\(</parameter></parameters>
  <customMessage><![CDATA[
      Are you sure that you want to throw Error? In most cases, you should use appropriate Exception instead.
      If you must throw Error, wrap the code block with
      // scalastyle:off throwerror
      throw new XXXError(...)
      // scalastyle:on throwerror
    ]]></customMessage>
 </check>

 <check customId="OmitBracesInCase" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
  <parameters><parameter name="regex">case[^\n>]*=>\s*\{</parameter></parameters>
  <customMessage>Omit braces in case clauses.</customMessage>
 </check>


 <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="true"></check>

 <check customId="argcount" level="error" class="org.scalastyle.scalariform.ParameterNumberChecker" enabled="true">
  <parameters>
   <parameter name="maxParameters"><![CDATA[10]]></parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker" enabled="true"></check>
 <check level="error" class="org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.NoFinalizeChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.CovariantEqualsChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.StructuralTypeChecker" enabled="true"></check>

 <check customId="println" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
  <parameters><parameter name="regex">^println$</parameter></parameters>
  <customMessage><![CDATA[Are you sure you want to println? If yes, wrap the code block with
      // scalastyle:off println
      println(...)
      // scalastyle:on println]]></customMessage>
 </check>

 <check level="error" class="org.scalastyle.scalariform.UppercaseLChecker" enabled="true"></check>

 <check level="error" class="org.scalastyle.scalariform.MethodNamesChecker" enabled="true">
  <parameters>
   <parameter name="regex"><![CDATA[^[a-z][A-Za-z0-9]*$]]></parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceBeforeTokenChecker" enabled="true">
  <parameters>
   <parameter name="tokens">ARROW, EQUALS, ELSE, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
  </parameters>
 </check>

 <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceAfterTokenChecker" enabled="true">
  <parameters>
   <parameter name="tokens">ARROW, EQUALS, COMMA, COLON, IF, ELSE, DO, WHILE, FOR, MATCH, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
  </parameters>
 </check>

 <!-- ================================================================================ -->
 <!--       rules we'd like to enforce, but haven't cleaned up the codebase yet        -->
 <!-- ================================================================================ -->

 <check level="error" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" enabled="false">
  <parameters>
   <parameter name="maxMethods"><![CDATA[30]]></parameter>
  </parameters>
 </check>

 <!-- ================================================================================ -->
 <!--                               rules we don't want                                -->
 <!-- ================================================================================ -->

 <!-- This one complains about all kinds of random things. Disable. -->
 <check level="error" class="org.scalastyle.scalariform.SimplifyBooleanExpressionChecker" enabled="false"></check>

 <check level="error" class="org.scalastyle.scalariform.MethodLengthChecker" enabled="false">
  <parameters>
   <parameter name="maxLength"><![CDATA[50]]></parameter>
  </parameters>
 </check>

 <!-- We want the opposite of this: NewLineAtEofChecker -->
 <check level="error" class="org.scalastyle.file.NoNewLineAtEofChecker" enabled="false"></check>

 <check level="warning" class="org.scalastyle.scalariform.IllegalImportsChecker" enabled="true">
  <parameters>
   <parameter name="illegalImports"><![CDATA[sun._,java.awt._]]></parameter>
  </parameters>
 </check>

 <!-- Doesn't seem super big deal here, and we have a lot of magic numbers ... -->
 <check level="error" class="org.scalastyle.scalariform.MagicNumberChecker" enabled="false">
  <parameters><parameter name="ignore">-1,0,1,2,3</parameter></parameters>
 </check>

 <!-- Doesn't seem super big deal here ... -->
 <check level="error" class="org.scalastyle.scalariform.CyclomaticComplexityChecker" enabled="false">
  <parameters><parameter name="maximum">10</parameter></parameters>
 </check>

 <!-- Doesn't seem super big deal here ... -->
 <check level="error" class="org.scalastyle.scalariform.NumberOfTypesChecker" enabled="false">
  <parameters><parameter name="maxTypes">30</parameter></parameters>
 </check>

 <!-- Doesn't seem super big deal here ... -->
 <check level="error" class="org.scalastyle.scalariform.NoCloneChecker" enabled="false"></check>

 <!-- We use null a lot in index creation -->
 <check level="error" class="org.scalastyle.scalariform.NullChecker" enabled="false"></check>

 <!-- We use return quite a bit for control flows and guards -->
 <check level="error" class="org.scalastyle.scalariform.ReturnChecker" enabled="false"></check>
</scalastyle>