scalastyle-config.xml

<!--
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.scalariform.EnsureSingleSpaceAfterTokenChecker" enabled="true" />

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

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

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

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

    <check level="error" class="org.scalastyle.file.FileLineLengthChecker" enabled="true">
        <parameters>
            <parameter name="maxLineLength"><![CDATA[300]]></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[[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 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 level="error" class="org.scalastyle.scalariform.CovariantEqualsChecker" enabled="true" />

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

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

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

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

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

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

    <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>

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

    <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 customId="visiblefortesting" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
        <parameters><parameter name="regex">@VisibleForTesting</parameter></parameters>
        <customMessage><![CDATA[
      @VisibleForTesting causes classpath issues. Please note this in the java doc instead (SPARK-11615).
    ]]></customMessage>
    </check>

    <check customId="runtimeaddshutdownhook" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
        <parameters><parameter name="regex">Runtime\.getRuntime\.addShutdownHook</parameter></parameters>
        <customMessage><![CDATA[
      Are you sure that you want to use Runtime.getRuntime.addShutdownHook? In most cases, you should use
      ShutdownHookManager.addShutdownHook instead.
      If you must use Runtime.getRuntime.addShutdownHook, wrap the code block with
      // scalastyle:off runtimeaddshutdownhook
      Runtime.getRuntime.addShutdownHook(...)
      // scalastyle:on runtimeaddshutdownhook
    ]]></customMessage>
    </check>

    <check customId="mutablesynchronizedbuffer" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
        <parameters><parameter name="regex">mutable\.SynchronizedBuffer</parameter></parameters>
        <customMessage><![CDATA[
      Are you sure that you want to use mutable.SynchronizedBuffer? In most cases, you should use
      java.utils.concurrent.ConcurrentLinkedQueue instead.
      If you must use mutable.SynchronizedBuffer, wrap the code block with
      // scalastyle:off mutablesynchronizedbuffer
      mutable.SynchronizedBuffer[...]
      // scalastyle:on mutablesynchronizedbuffer
    ]]></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>

    <check customId="javaconversions" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
        <parameters><parameter name="regex">JavaConversions</parameter></parameters>
        <customMessage>Instead of importing implicits in scala.collection.JavaConversions._, import
            scala.collection.JavaConverters._ and use .asScala / .asJava methods</customMessage>
    </check>

    <check customId="commonslang2" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
        <parameters><parameter name="regex">org\.apache\.commons\.lang\.</parameter></parameters>
        <customMessage>Use Commons Lang 3 classes (package org.apache.commons.lang3.*) instead
            of Commons Lang 2 (package org.apache.commons.lang.*)</customMessage>
    </check>

    <check customId="extractopt" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
        <parameters><parameter name="regex">extractOpt</parameter></parameters>
        <customMessage>Use Utils.jsonOption(x).map(.extract[T]) instead of .extractOpt[T], as the latter
            is slower.  </customMessage>
    </check>

    <check level="warning" class="org.scalastyle.scalariform.ImportOrderChecker" enabled="true">
        <parameters>
            <parameter name="groups">java,scala,3rdParty,spark</parameter>
            <parameter name="group.java">javax?\..*</parameter>
            <parameter name="group.scala">scala\..*</parameter>
        </parameters>
    </check>

    <check level="error" class="org.scalastyle.scalariform.DisallowSpaceBeforeTokenChecker" enabled="true">
        <parameters>
            <parameter name="tokens">COMMA</parameter>
        </parameters>
    </check>

    <check customId="SingleSpaceBetweenRParenAndLCurlyBrace" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
        <parameters><parameter name="regex">\)\{</parameter></parameters>
        <customMessage><![CDATA[
      Single Space between ')' and `{`.
    ]]></customMessage>
    </check>

    <check customId="NoScalaDoc" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
        <parameters><parameter name="regex">(?m)^(\s*)/[*][*].*$(\r|)\n^\1 [*]</parameter></parameters>
        <customMessage>Use Javadoc style indentation for multiline comments</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>

    <!-- SPARK-16877: Avoid Java annotations -->
    <check customId="OverrideJavaCase" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="true">
        <parameters><parameter name="regex">^Override$</parameter></parameters>
        <customMessage>override modifier should be used instead of @java.lang.Override.</customMessage>
    </check>

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

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

    <!-- This breaks symbolic method names so we don't turn it on. -->
    <!-- Maybe we should update it to allow basic symbolic names, and then we are good to go. -->
    <check level="error" class="org.scalastyle.scalariform.MethodNamesChecker" enabled="false">
        <parameters>
            <parameter name="regex"><![CDATA[^[a-z][A-Za-z0-9]*$]]></parameter>
        </parameters>
    </check>

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

    <check customId="funsuite" level="error" class="org.scalastyle.scalariform.TokenChecker" enabled="false">
        <parameters><parameter name="regex">^FunSuite[A-Za-z]*$</parameter></parameters>
        <customMessage>Tests must extend org.apache.spark.SparkFunSuite instead.</customMessage>
    </check>

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

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

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

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

    <!-- We use null a lot in low level code and to interface with 3rd party code -->
    <check level="error" class="org.scalastyle.scalariform.NullChecker" enabled="false" />

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

    <!-- Doesn't seem super big deal here ... -->
    <check level="error" class="org.scalastyle.file.FileLengthChecker" enabled="false">
        <parameters><parameter name="maxFileLength">500></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.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.MethodLengthChecker" enabled="false">
        <parameters><parameter name="maxLength">50</parameter></parameters>
    </check>

    <!-- Not exactly feasible to enforce this right now. -->
    <check level="error" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" enabled="false">
        <parameters><parameter name="maxMethods"><![CDATA[30]]></parameter></parameters>
    </check>

    <check level="error" class="org.scalastyle.scalariform.MagicNumberChecker" enabled="false">
        <parameters><parameter name="ignore">-1,0,1,2,3</parameter></parameters>
    </check>

</scalastyle>