dupl

dupl is a tool written in Go for finding code clones. So far it can find clones only in the Go source files. The method uses suffix tree for serialized ASTs. It ignores values of AST nodes. It just operates with their types (e.g. if a == 13 {} and if x == 100 {} are considered the same provided it exceeds the minimal token sequence size).

Due to the used method dupl can report so called "false positives" on the output. These are the ones we do not consider clones (whether they are too small, or the values of the matched tokens are completely different).

Installation

go get -u github.com/golangci/dupl

Usage

Usage of dupl:
  dupl [flags] [paths]

Paths:
  If the given path is a file, dupl will use it regardless of
  the file extension. If it is a directory it will recursively
  search for *.go files in that directory.

  If no path is given dupl will recursively search for *.go
  files in the current directory.

Flags:
  -files
        read file names from stdin one at each line
  -html
        output the results as HTML, including duplicate code fragments
  -plumbing
        plumbing (easy-to-parse) output for consumption by scripts or tools
  -t, -threshold size
        minimum token sequence size as a clone (default 15)
  -vendor
        check files in vendor directory
  -v, -verbose
        explain what is being done

Examples:
  dupl -t 100
        Search clones in the current directory of size at least
        100 tokens.
  dupl $(find app/ -name '*_test.go')
        Search for clones in tests in the app directory.
  find app/ -name '*_test.go' |dupl -files
        The same as above.

Example

The reduced output of this command with the following parameters for the Docker source code looks like this.

$ dupl -t 200 -html >docker.html