andrewhunter0 / gradle-cpd-plugin

Gradle plugin to find duplicate code using PMDs copy/paste detection (= CPD).

Gradle CPD plugin

Table of Contents

• What is it
• Requirements
• Usage
• Options
• Contributing
• Release notes

What is it

A Gradle plugin to find duplicate code using PMDs copy/paste detection (= CPD).

Requirements

Currently this plugin requires PMD greater or equal to version 5.2 such that toolVersion >= v5.2.0.

Explaination: As PMDs source code and artifacts were modularized into modules for every language with v5.2.0 (see Changelog - 5.2.0) this plugin uses the 'pmd-dist' dependency by default. This dependency further includes 'pmd-core', 'pmd-java', 'pmd-cpp', ... transitively. This also forces proper working of toolVersion to PMD v5.2.0 and higher. If you want to use a version prior to v5.2.0, you can use the following snipped

dependencies {
    cpd 'net.sourceforge.pmd:pmd:5.0.5'
}

Usage

This plugin is available using either the new Gradle plugins DSL

plugins {
    id 'de.aaschmid.cpd' version '1.0'
}

or the old fashion buildscript block from Maven Central or jCenter.

buildscript {
    repositories {
        // choose your prefered one
        mavenCentral()
        jcenter()
    }

    dependencies {
        classpath 'de.aaschmid:gradle-cpd-plugin:1.0'
    }
}
apply plugin: 'cpd'

Attention: The plugins groupId was changed from de.aaschmid.gradle.plugins to de.aaschmid in v1.0.

By default the copy-paste-detection looks at all source code of all projects which at least apply JavaBasePlugin. If you use a different programming language and want to get it configurated out of the box, please open an issue :-)

Single module project

If you have a single module project you just need to make sure that the JavaBasePlugin is also applied to it (explicitly or implicitly through e.g. Java or Groovy plugin). Otherwise you can simply add a dependency to a task you like by

analyze.dependsOn(cpdCheck)

Multi module project

If the root project of your multi-module project applies the JavaBasePlugin, you are done. But most likely this is not how your project looks like. If so, you need to manually add a task graph dependency manually to either one or all of your subprojects such that the cpdCheck task is executed:

// one single subproject where 'JavaBasePlugin' is available
subprojectOne.check.dependsOn(':cpdCheck')

// all subprojects where 'check' task is available (which comes with 'JavaBasePlugin')
subprojects {
    plugins.withType(JavaBasePlugin) { // <- just if 'JavaBasePlugin' plugin is not applied to all subprojects
        check.dependsOn(rootProject.cpdCheck)
    }
}

Examples

This example shows a project where only main sources should be checked for duplicates:

// optional - settings for every CPD task
cpd {
    language = 'cpp'
    toolVersion = '5.2.3' // defaults to '5.4.2'; just available for v5.2.0 and higher (see explanation above)
}

// optional - default report is xml and default sources are 'main' and 'test'
cpdCheck {
    reports {
        text.enabled = true
        xml.enabled = false
    }
    source = sourceSets.main.allJava // only java, groovy and scala classes in 'main' sourceSets
}

Note: With v0.2, I have renamed the default task from cpd to cpdCheck that it does not have a name clash anymore.

Options

This plugin supports the following options, either set for the plugin using cpd { } or for every task explicitly, e.g. using cpdCheck { }:

Attribute	Default	Applies for language	since
encoding	System default		v0.1
ignoreAnnotations	false	'java'	v0.4
ignoreFailures	false		v0.1
ignoreIdentifiers	false	'java'	v0.4
ignoreLiterals	false	'java'	v0.4
language	'java'		v0.4
minimumTokenCount	50		v0.1
skipDuplicateFiles	false		v0.5
skipLexicalErrors	false		v0.5
skipBlocks	true	'cpp'	v0.4
skipBlocksPattern	```'#if 0	#endif'```	'cpp'

For more information about options and their descriptions, see here, and for the available programming languages have a look on CPD documentation. To request more options, please file an issue here.

Additionally, one can configure the following reports for every task analogous to Reporting as for any other reporting plugin. See also the example in Usage section above.

Report	Default	Further options and their defaults
csv	disabled	separator = ','
text	disabled	lineSeparator = '=====================================================================', trimLeadingCommonSourceWhitespaces = false
xml	enabled	encoding = <<System default>>

Contributing

You are very welcome to contribute by providing a patch/pull request.

Please note that running the test cases my take quite long becuase the acceptance test cases (see de.aaschmid.gradle.plugins.cpd.test.CpdAcceptanceTest will download CPD and its dependencies for every version. I recommend to get these dependencies in your localMaven() repository as the test cases look there for it first.