I'm working on a proprietary legacy code base and some variables are camel-cased while others are snake-cased. I'd like to clean up and enforce only camel-cased variable names but I can't seem to find a sniff for that. Here are the contents of my custom ruleset.
The ruleset.xml standard contains 68 sniffs
Generic (22 sniffs)
-------------------
Generic.Classes.DuplicateClassName
Generic.CodeAnalysis.ForLoopShouldBeWhileLoop
Generic.CodeAnalysis.UnconditionalIfStatement
Generic.CodeAnalysis.UnnecessaryFinalModifier
Generic.CodeAnalysis.UnusedFunctionParameter
Generic.CodeAnalysis.UselessOverridingMethod
Generic.Commenting.Fixme
Generic.Commenting.Todo
Generic.ControlStructures.InlineControlStructure
Generic.Files.ByteOrderMark
Generic.Files.LineEndings
Generic.Files.LineLength
Generic.Formatting.DisallowMultipleStatements
Generic.Formatting.NoSpaceAfterCast
Generic.Functions.FunctionCallArgumentSpacing
Generic.NamingConventions.CamelCapsFunctionName
Generic.NamingConventions.UpperCaseConstantName
Generic.PHP.DisallowShortOpenTag
Generic.PHP.LowerCaseConstant
Generic.PHP.LowerCaseKeyword
Generic.WhiteSpace.DisallowTabIndent
Generic.WhiteSpace.ScopeIndent
PEAR (5 sniffs)
---------------
PEAR.Commenting.InlineComment
PEAR.Formatting.MultiLineAssignment
PEAR.Functions.ValidDefaultValue
PEAR.WhiteSpace.ScopeClosingBrace
PEAR.WhiteSpace.ScopeIndent
PSR1 (3 sniffs)
---------------
PSR1.Classes.ClassDeclaration
PSR1.Files.SideEffects
PSR1.Methods.CamelCapsMethodName
PSR2 (12 sniffs)
----------------
PSR2.Classes.ClassDeclaration
PSR2.Classes.PropertyDeclaration
PSR2.ControlStructures.ControlStructureSpacing
PSR2.ControlStructures.ElseIfDeclaration
PSR2.ControlStructures.SwitchDeclaration
PSR2.Files.ClosingTag
PSR2.Files.EndFileNewline
PSR2.Methods.FunctionCallSignature
PSR2.Methods.FunctionClosingBrace
PSR2.Methods.MethodDeclaration
PSR2.Namespaces.NamespaceDeclaration
PSR2.Namespaces.UseDeclaration
Squiz (26 sniffs)
-----------------
Squiz.Classes.ValidClassName
Squiz.ControlStructures.ControlSignature
Squiz.ControlStructures.ForEachLoopDeclaration
Squiz.ControlStructures.ForLoopDeclaration
Squiz.ControlStructures.LowercaseDeclaration
Squiz.Functions.FunctionDeclarationArgumentSpacing
Squiz.Functions.FunctionDeclaration
Squiz.Functions.LowercaseFunctionKeywords
Squiz.Functions.MultiLineFunctionDeclaration
Squiz.PHP.CommentedOutCode
Squiz.PHP.Eval
Squiz.PHP.GlobalKeyword
Squiz.PHP.Heredoc
Squiz.PHP.InnerFunctions
Squiz.PHP.LowercasePHPFunctions
Squiz.PHP.NonExecutableCode
Squiz.Scope.MethodScope
Squiz.Scope.StaticThisUsage
Squiz.WhiteSpace.ControlStructureSpacing
Squiz.WhiteSpace.ObjectOperatorSpacing
Squiz.WhiteSpace.OperatorSpacing
Squiz.WhiteSpace.PropertyLabelSpacing
Squiz.WhiteSpace.ScopeClosingBrace
Squiz.WhiteSpace.ScopeKeywordSpacing
Squiz.WhiteSpace.SemicolonSpacing
Squiz.WhiteSpace.SuperfluousWhitespace
You'll want to use the Squiz.NamingConventions.ValidVariableName sniff to check variable names.
This sniff currently includes 5 different error codes. 3 of them are checking that variables, member vars, and vars inside strings are all camel-cased. The other 2 codes enforce that private member vars begin with an underscore.
To just ensure that variables are camel-cased, include this in your ruleset if you are using PHPCS version 3:
<rule ref="Squiz.NamingConventions.ValidVariableName.NotCamelCaps"/>
If you also want to ensure member vars and string vars are camel-cased, include these if you are using version 3:
<rule ref="Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps"/>
<rule ref="Squiz.NamingConventions.ValidVariableName.StringNotCamelCaps"/>
If you want the whole lot, include this:
<rule ref="Squiz.NamingConventions.ValidVariableName"/>
PHPCS version 2 does not let you include specific sniff codes, so you will first need to include the entire sniff and then exclude the specific codes you don't want by setting their severity to 0. So if you want just the 3 camel-case checks and you are using version 2, put this in your ruleset:
<rule ref="Squiz.NamingConventions.ValidVariableName"/>
<rule ref="Squiz.NamingConventions.ValidVariableName.PublicHasUnderscore">
<severity>0</severity>
</rule>
<rule ref="Squiz.NamingConventions.ValidVariableName.PrivateNoUnderscore">
<severity>0</severity>
</rule>