checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
    "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">

<module name="Checker">
    <!-- Restricts scan to specific extensions.           -->
    <!-- See http://checkstyle.sf.net/config.html#Checker -->
    <property name="fileExtensions" value="java, kt, xml"/>

    <!-- Excludes given file patterns from scan.              -->
    <!-- See http://checkstyle.sf.net/config_filefilters.html -->
    <module name="BeforeExecutionExclusionFileFilter">
        <property name="fileNamePattern" value="[/\\]gen[/\\]|[/\\]node_modules[/\\]|[/\\]gutenberg-mobile[/\\]|[/\\]react-native-aztec[/\\]"/>
    </module>

    <!-- Checks whether files end with a new line.                        -->
    <!-- See http://checkstyle.sf.net/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile"/>

    <!-- Checks that property files contain the same keys.         -->
    <!-- See http://checkstyle.sf.net/config_misc.html#Translation -->
    <module name="Translation"/>

    <!-- Checks for Size Violations.                    -->
    <!-- See http://checkstyle.sf.net/config_sizes.html -->
    <!--
    <module name="FileLength"/>
    -->

    <!-- Checks for whitespace                               -->
    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
    <module name="FileTabCharacter"/>

    <!-- Miscellaneous other checks.                   -->
    <!-- See http://checkstyle.sf.net/config_misc.html -->
    <module name="RegexpMultiline">
      <property name="format"
                value="(\n|\r\n)[\t ]*(\n|\r\n)[\t ]*\}"/>
      <property name="message" value="Empty line not allowed before brace"/>
    </module>

    <module name="RegexpMultiline">
      <property name="format"
                value="\{[\t ]*(\n|\r\n)[\t ]*(\n|\r\n)"/>
      <property name="message" value="Empty line not allowed after brace"/>
    </module>

    <module name="RegexpSingleline">
      <property name="format" value=" \/\/(?!noinspection)[^ \t]"/>
      <property name="message" value="Line comments '//' must be followed by one whitespace"/>
      <property name="severity" value="error"/>
    </module>

    <module name="RegexpSingleline">
        <property name="format" value="[^\S\r\n]@[\S]*(\([{]?\&quot;.*\&quot;[}]?\)++|\([^\&quot;]*\)++)[^ \t]"/>
        <property name="message" value="In-line annotations must be followed by one whitespace"/>
        <property name="severity" value="error"/>
    </module>

    <module name="RegexpSingleline">
        <property name="format" value="^(?!.*\bimport\b).*Store\.[A-Z][A-Za-z0-9]*[ );]"/>
        <property name="message" value="Specific imports should be used for FluxC Store inner classes"/>
        <property name="severity" value="error"/>
    </module>

    <module name="RegexpMultiline">
        <property name="format" value="@Inject(\n|\r\n).*[^{,(]$"/>
        <property name="message" value="Inject annotation should be in-line with the annotated field or property"/>
        <property name="fileExtensions" value="java"/>
    </module>

    <module name="RegexpSingleline">
        <property name="format" value="^(?!.*\bclass\b).*\S.*@Inject"/>
        <property name="message" value="In-line inject annotation should precede the rest of the declaration"/>
        <property name="fileExtensions" value="java"/>
    </module>

    <!-- Specific to FluxC -->
    <module name="RegexpSingleline">
        <property name="format" value="extends Payload[^&lt;]"/>
        <property name="message" value="Payload should not be used as a raw type"/>
        <property name="severity" value="error"/>
    </module>

    <!-- Specific to FluxC -->
    <module name="RegexpMultiline">
        <property name="format" value="(?&lt;!^@Singleton)\n.*extends Store[\s{]"/>
        <property name="message" value="Stores must be annotated with @Singleton"/>
    </module>

    <!-- Specific to FluxC -->
    <module name="RegexpMultiline">
        <property name="format" value="(?&lt;!^@Singleton)\n.*extends Base[\w]*Client[\s{]"/>
        <property name="message" value="Network clients must be annotated with @Singleton"/>
    </module>

    <!-- Specific to WordPress -->
    <module name="RegexpSingleline">
      <property name="format" value=".*dotcom(?!.*checkstyle ignore)"/>
      <property name="ignoreCase" value="true"/>
      <property name="message" value="You should not use _dotcom_, use _wpcom_ instead"/>
      <property name="severity" value="error"/>
    </module>

    <!-- Specific to WordPress -->
    <module name="RegexpSingleline">
      <property name="format" value=".*dotorg(?!.*checkstyle ignore)"/>
      <property name="ignoreCase" value="true"/>
      <property name="message" value="You should not use _dotorg_, use _selfHosted_ instead"/>
      <property name="severity" value="error"/>
    </module>

    <!-- Specific to WordPress -->
    <module name="RegexpSingleline">
      <property name="format" value=" Snackbar\.make(?!.*checkstyle ignore)"/>
      <property name="ignoreCase" value="true"/>
      <property name="message" value="You should not use Snackbar directly, use WPSnackbar instead"/>
      <property name="severity" value="error"/>
    </module>

    <module name="LineLength">
        <property name="fileExtensions" value="java"/>
        <!-- what is a good max value? -->
        <property name="max" value="120"/>
        <!-- ignore lines like "$File: //depot/... $ and package or import statements" -->
        <property name="ignorePattern" value="\$File.*\$|^(package|import) .*"/>
        <property name="severity" value="error"/>
    </module>

    <module name="TreeWalker">

        <!-- Checks for Naming Conventions.                  -->
        <!-- See http://checkstyle.sf.net/config_naming.html -->
        <module name="ConstantName"/>
        <module name="LocalFinalVariableName"/>
        <module name="LocalVariableName"/>
        <!-- <module name="MemberName"/> -->
        <module name="MemberName">
          <property name="applyToPublic" value="false"/>
          <property name="applyToProtected" value="false"/>
          <property name="applyToPackage" value="false"/>
          <property name="applyToPrivate" value="false"/>
          <property name="format" value="^[a-zA-Z0-9]*$"/>
        </module>
        <module name="MemberName">
          <property name="applyToPublic" value="false"/>
          <property name="applyToProtected" value="true"/>
          <property name="applyToPackage" value="true"/>
          <property name="applyToPrivate" value="true"/>
          <property name="format" value="^m[a-zA-Z0-9]*$"/>
        </module>

        <module name="MethodName">
           <property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/>
        </module>
        <module name="PackageName"/>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName">
          <property name="format" value="^[A-Z][a-zA-Z0-9_]*$"/>
        </module>

        <!-- Checks for imports                              -->
        <!-- See http://checkstyle.sf.net/config_import.html -->
        <module name="AvoidStarImport"/>
        <module name="IllegalImport">
            <property name="illegalClasses" value="android.app.Fragment"/>
        </module>
        <module name="RedundantImport"/>
        <module name="UnusedImports">
            <property name="processJavadoc" value="true"/>
        </module>

        <module name="ImportOrder">
            <property name="groups" value="android,androidx,com,junit,net,org,java,javax"/>
            <property name="ordered" value="false"/>
            <property name="separated" value="true"/>
            <property name="option" value="bottom"/>
            <property name="sortStaticImportsAlphabetically" value="true"/>
        </module>

        <!-- Checks for Size Violations.                    -->
        <!-- See http://checkstyle.sf.net/config_sizes.html -->
        <module name="MethodLength">
          <property name="tokens" value="METHOD_DEF"/>
          <!-- TODO: We should set this value around 40 or 50 -->
          <property name="max" value="200"/>
          <property name="severity" value="warning"/>
        </module>

        <!-- Checks for whitespace                               -->
        <!-- See http://checkstyle.sf.net/config_whitespace.html -->
        <module name="EmptyForIteratorPad"/>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="SingleSpaceSeparator"/>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround">
          <property name="allowEmptyTypes" value="true"/>
          <property name="allowEmptyConstructors" value="true"/>
          <property name="ignoreEnhancedForColon" value="false"/>
        </module>
        <module name="NoWhitespaceAfter">
          <property name="tokens"
                    value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS, UNARY_PLUS" />
        </module>

        <!-- Modifier Checks                                    -->
        <!-- See http://checkstyle.sf.net/config_modifiers.html -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier"/>


        <!-- Checks for blocks. You know, those {}'s         -->
        <!-- See http://checkstyle.sf.net/config_blocks.html -->
        <module name="AvoidNestedBlocks"/>
        <module name="EmptyBlock">
          <property name="option" value="text"/>
        </module>
        <module name="LeftCurly"/>
        <module name="NeedBraces">
            <property name="allowSingleLineStatement" value="true"/>
        </module>
        <module name="RightCurly"/>


        <!-- Checks for common coding problems               -->
        <!-- See http://checkstyle.sf.net/config_coding.html -->
        <module name="EmptyStatement"/>
        <module name="FallThrough"/>
        <module name="HiddenField">
          <property name="ignoreConstructorParameter" value="true"/>
          <property name="ignoreSetter" value="true"/>
          <property name="severity" value="warning"/>
        </module>
        <module name="IllegalInstantiation"/>

        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>

        <!-- Checks for class design                         -->
        <!-- See http://checkstyle.sf.net/config_design.html -->
        <module name="InterfaceIsType"/>
        <module name="VisibilityModifier">
          <property name="packageAllowed" value="true"/>
          <property name="protectedAllowed" value="true"/>
          <property name="publicMemberPattern" value="^[a-zA-Z0-9_]*$"/>
        </module>

        <!-- Miscellaneous other checks.                   -->
        <!-- See http://checkstyle.sf.net/config_misc.html -->
        <module name="ArrayTypeStyle"/>
        <module name="TodoComment">
          <property name="format" value="FIXME"/>
          <property name="severity" value="warning"/>
        </module>

        <module name="UpperEll"/>

        <module name="SuppressWarningsHolder"/> <!-- Required by suppression via annotation filter -->

        <module name="OneStatementPerLine"/>

        <!-- Enable suppression comments -->
        <module name="SuppressionCommentFilter">
            <property name="offCommentFormat" value="CHECKSTYLE IGNORE\s+(\S+)"/>
            <property name="onCommentFormat" value="CHECKSTYLE END IGNORE\s+(\S+)"/>
            <property name="checkFormat" value="$1"/>
        </module>

        <module name="SuppressWithNearbyCommentFilter">
            <!-- Syntax is "SUPPRESS CHECKSTYLE name" -->
            <property name="commentFormat" value="SUPPRESS CHECKSTYLE (\w+)"/>
            <property name="checkFormat" value="$1"/>
            <property name="influenceFormat" value="1"/>
        </module>

    </module>

    <module name="SuppressWarningsFilter"/>

</module>