Don't force public variables to use Hungarian notation (#8774)

People generally have expressed a dislike for the Hungarian notation
used in member variables, especially in examples/templates, and our
styleguide shouldn't be forced on downstream consumers, so this removes
all Hungarian notation from the examples/templates.

There are _some_ benefits to Hungarian for private member variables
(like knowing what's a member vs. local in a PR review) so we'll keep
private member variables the same for now, but public variables should
no longer use Hungarian notation, since it looks much worse. A new PMD
XPath rule has been added to accomplish this goal. Some other
non-compliant variables were fixed for the new rule.

styleguide/checkstyle-suppressions.xml

@@ -7,12 +7,12 @@ suppressions PUBLIC "-//Puppy Crawl//DTD Suppressions 1.1//EN"
   <suppress files=".*wpilibjIntegrationTests.*"
     checks="MissingJavadocMethod" />
   <suppress files="wpimath.*"
-    checks="(LocalVariableName|MemberName|MethodName|MethodTypeParameterName|ParameterName)" />
+    checks="(LocalVariableName|MethodName|MethodTypeParameterName|ParameterName)" />
   <suppress files=".*JNI.*"
     checks="(EmptyLineSeparator|LineLength|MissingJavadocMethod|ParameterName)" />
   <!-- Disable checks for generated protobuf files -->
   <suppress files=".*generated[/\\].*[/\\]proto[/\\].*"
-    checks="(CustomImportOrder|EmptyLineSeparator|LeftCurly|LineLength|JavadocParagraph|MemberName|MissingJavadocMethod|OverloadMethodsDeclarationOrder|SummaryJavadoc|UnnecessaryParentheses|OperatorWrap|JavadocMethod|JavadocTagContinuationIndentation)" />
+    checks="(CustomImportOrder|EmptyLineSeparator|LeftCurly|LineLength|JavadocParagraph|MissingJavadocMethod|OverloadMethodsDeclarationOrder|SummaryJavadoc|UnnecessaryParentheses|OperatorWrap|JavadocMethod|JavadocTagContinuationIndentation)" />
   <suppress files="wpilibj[/\\]src[/\\]generated.*"
     checks="MethodName" />
   <!-- Disable checkstyle for generated unit files -->

styleguide/checkstyle.xml

@@ -168,12 +168,6 @@ module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
       <message key="name.invalidPattern"
         value="Type name ''{0}'' must match pattern ''{1}''." />
     </module>
-    <module name="MemberName">
-      <property name="format"
-        value="^(m_([a-zA-Z]|[a-z][a-zA-Z0-9]+)|value)$" />
-      <message key="name.invalidPattern"
-        value="Member name ''{0}'' must match pattern ''{1}''." />
-    </module>
     <module name="ParameterName">
       <property name="format"
         value="^([a-zA-Z]|[a-z][a-zA-Z0-9]+)$" />

styleguide/pmd-ruleset.xml

@@ -12,7 +12,7 @@
   <exclude-pattern>.*/Timestamped.*\.java</exclude-pattern>
   <exclude-pattern>.*/units/measure/.*\.java</exclude-pattern>
 
-  <exclude-pattern>.*/*IntegrationTests.*</exclude-pattern>
+  <exclude-pattern>.*/*Examples.*</exclude-pattern>
   <exclude-pattern>.*/*JNI.*</exclude-pattern>
   <exclude-pattern>.*/math/proto.*</exclude-pattern>
   <exclude-pattern>.*/command3/proto.*</exclude-pattern>
@@ -143,4 +143,22 @@
             ]]>
     </example>
   </rule>
+  <rule name="PublicFieldNamingConvention"
+        language="java"
+        message="Public fields must follow lowerCamelCase."
+        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
+    <description>
+
+    </description>
+    <priority>3</priority>
+    <properties>
+      <property name="xpath">
+        <value>
+  <![CDATA[
+  //ClassDeclaration[not(matches(@PackageName, "org.wpilib.math"))]/ClassBody/FieldDeclaration[@Visibility = 'public' and @Static = false()]/VariableDeclarator[not(matches(@Name, "^[a-z][a-zA-Z0-9]*$"))]
+  ]]>
+        </value>
+      </property>
+    </properties>
+  </rule>
 </ruleset>

styleguide/spotbugs-exclude.xml

@@ -150,6 +150,10 @@
     <Bug pattern="UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD" />
     <Class name="org.wpilib.epilogue.EpilogueConfiguration" />
   </Match>
+  <Match>
+    <Bug pattern="URF_UNREAD_FIELD" />
+    <Class name="org.wpilib.driverstation.internal.DriverStationBackend$HALJoystickAxesRaw" />
+  </Match>
   <Match>
     <!-- PMD will skip variables named `ignore`, but spotbugs isn't as smart -->
     <Bug pattern="DLS_DEAD_LOCAL_STORE" />