scalastyle-config.xml

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<!--

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.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[[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>

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

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

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

  <!-- As of SPARK-7977 all printlns need to be wrapped in '// scalastyle:off/on println' -->
  <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="sparklogging" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
    <parameters><parameter name="regex">org.apache.spark.Logging</parameter></parameters>
    <customMessage><![CDATA[Do not rely on Spark's Logging trait.]]></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        -->
  <!-- ================================================================================ -->

  <!-- We cannot turn the following two on, because it'd fail a lot of string interpolation use cases. -->
  <!-- Ideally the following two rules should be configurable to rule out string interpolation. -->
  <check level="error" class="org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker" enabled="false"></check>
  <check level="error" class="org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker" enabled="false"></check>

  <!-- 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>

  <!-- Should turn this on, but we have a few places that need to be fixed first -->
  <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker" enabled="false"></check>

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

  <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"></check>

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

  <!-- 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"></check>

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

  <!-- Doesn't seem super big deal here ... -->
  <check level="error" class="org.scalastyle.file.FileLengthChecker" enabled="false">
    <parameters><parameter name="maxFileLength">800></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. -->
  <!-- It is also infrequent that somebody introduces a new class with a lot of methods. -->
  <check level="error" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" enabled="false">
    <parameters><parameter name="maxMethods"><![CDATA[30]]></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>

</scalastyle>