David M. Karr (fullname at gmail.com)
b80b99bfc8
The current CPD documentation covers very well how to use it, but there was no information here that describes why someone would care about how much duplicate code they have. The developers I work with want to "cheat" on their SonarQube quality gates by excluding some code from CPD checks, because they don't really understand what the problem is. Ironically, the main risk from duplicate code is when that code unintentionally becomes not duplicate anymore, creating a hidden problem that may or may not erupt on you. The text I've added here is excerpted from a short tech note I wrote to my team on the subject.
PMD
About
PMD is a source code analyzer. It finds common programming flaws like unused variables, empty catch blocks, unnecessary object creation, and so forth. It supports Java, JavaScript, Salesforce.com Apex and Visualforce, PLSQL, Apache Velocity, XML, XSL.
Additionally it includes CPD, the copy-paste-detector. CPD finds duplicated code in Java, C, C++, C#, Groovy, PHP, Ruby, Fortran, JavaScript, PLSQL, Apache Velocity, Scala, Objective C, Salesforce.com Apex, Perl, Swift, Matlab, Python.
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